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Margalho LP, Graça JS, Kamimura BA, Lee SHI, Canales HDS, Chincha AIA, Caturla MYR, Brexó RP, Crucello A, Alvarenga VO, Cruz AG, Oliveira CAF, Sant'Ana AS. Enterotoxigenic Staphylococcus aureus in Brazilian artisanal cheeses: Occurrence, counts, phenotypic and genotypic profiles. Food Microbiol 2024; 121:104531. [PMID: 38637091 DOI: 10.1016/j.fm.2024.104531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 03/24/2024] [Accepted: 04/02/2024] [Indexed: 04/20/2024]
Abstract
The present study aimed to assess the occurrence and counts of Staphylococcus aureus in Brazilian artisanal cheeses (BAC) produced in five regions of Brazil: Coalho and Manteiga (Northeast region); Colonial and Serrano (South); Caipira (Central-West); Marajó (North); and Minas Artisanal cheeses, from Araxá, Campos das Vertentes, Cerrado, Serro and Canastra microregions (Southeast). The resistance to chlorine-based sanitizers, ability to attach to stainless steel surfaces, and antibiogram profile of a large set of S. aureus strains (n = 585) were assessed. Further, a total of 42 isolates were evaluated for the presence of enterotoxigenic genes (sea, seb, sec, sed, see, seg, sei, sej, and ser) and submitted to typing using pulsed-field gel electrophoresis (PFGE). BAC presented high counts of S. aureus (3.4-6.4 log CFU/g), varying from 25 to 62.5%. From the S. aureus strains (n = 585) assessed, 16% could resist 200 ppm of sodium hypochlorite, whereas 87.6% produced strong ability to attach to stainless steel surfaces, corroborating with S. aureus ability to persist and spread in the environment. Furthermore, the relatively high frequency (80.5%) of multidrug-resistant S. aureus and the presence of enterotoxin genes in 92.6% of the strains is of utmost attention. It reveals the lurking threat of SFP that can survive when conditions are favorable. The presence of enterotoxigenic and antimicrobial-resistant strains of S. aureus in cheese constitutes a potential risk to public health. This result calls for better control of cheese contamination sources, and taking hygienic measures is necessary for food safety. More attention should be paid to animal welfare and hygiene practices in some dairy farms during manufacturing to enhance the microbiological quality of traditional cheese products.
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Affiliation(s)
- Larissa P Margalho
- Department of Food Science and Nutrition, Faculty of Food Engineering, University of Campinas, Campinas, SP, Brazil
| | - Juliana S Graça
- Department of Food Science and Nutrition, Faculty of Food Engineering, University of Campinas, Campinas, SP, Brazil
| | - Bruna A Kamimura
- Department of Food Science and Nutrition, Faculty of Food Engineering, University of Campinas, Campinas, SP, Brazil
| | - Sarah H I Lee
- Department of Food Engineering, School of Animal Science and Food Engineering, University of São Paulo, Pirassununga, SP, Brazil
| | - Héctor D S Canales
- Department of Food Science and Nutrition, Faculty of Food Engineering, University of Campinas, Campinas, SP, Brazil
| | - Alexandra I A Chincha
- Department of Food Science and Nutrition, Faculty of Food Engineering, University of Campinas, Campinas, SP, Brazil
| | - Magdevis Y R Caturla
- Department of Food Science and Nutrition, Faculty of Food Engineering, University of Campinas, Campinas, SP, Brazil
| | - Ramon P Brexó
- Department of Food Science and Nutrition, Faculty of Food Engineering, University of Campinas, Campinas, SP, Brazil
| | - Aline Crucello
- Department of Food Science and Nutrition, Faculty of Food Engineering, University of Campinas, Campinas, SP, Brazil
| | - Verônica O Alvarenga
- Department of Food Science and Nutrition, Faculty of Food Engineering, University of Campinas, Campinas, SP, Brazil; Department of Food, Faculty of Pharmacy, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Adriano G Cruz
- Department of Food, Instituto Federal de Educação, Ciência e Tecnologia do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Carlos Augusto F Oliveira
- Department of Food Engineering, School of Animal Science and Food Engineering, University of São Paulo, Pirassununga, SP, Brazil
| | - Anderson S Sant'Ana
- Department of Food Science and Nutrition, Faculty of Food Engineering, University of Campinas, Campinas, SP, Brazil.
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Ermann Lundberg L, Pallabi Mishra P, Liu P, Forsberg MM, Sverremark-Ekström E, Grompone G, Håkansson S, Linninge C, Roos S. Bifidobacterium longum subsp. longum BG-L47 boosts growth and activity of Limosilactobacillus reuteri DSM 17938 and its extracellular membrane vesicles. Appl Environ Microbiol 2024:e0024724. [PMID: 38888338 DOI: 10.1128/aem.00247-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Accepted: 05/14/2024] [Indexed: 06/20/2024] Open
Abstract
The aim of this study was to identify a Bifidobacterium strain that improves the performance of Limosilactobacillus reuteri DSM 17938. Initial tests showed that Bifidobacterium longum subsp. longum strains boosted the growth of DSM 17938 during in vivo-like conditions. Further characterization revealed that one of the strains, BG-L47, had better bile and acid tolerance compared to BG-L48, as well as mucus adhesion compared to both BG-L48 and the control strain BB536. BG-L47 also had the capacity to metabolize a broad range of carbohydrates and sugar alcohols. Mapping of glycoside hydrolase (GH) genes of BG-L47 and BB536 revealed many GHs associated with plant-fiber utilization. However, BG-L47 had a broader phenotypic fiber utilization capacity. In addition, B. longum subsp. longum cells boosted the bioactivity of extracellular membrane vesicles (MV) produced by L. reuteri DSM 17938 during co-cultivation. Secreted 5'-nucleotidase (5'NT), an enzyme that converts AMP into the signal molecule adenosine, was increased in MV boosted by BG-L47. The MV exerted an improved antagonistic effect on the pain receptor transient receptor potential vanilloid 1 (TRPV1) and increased the expression of the immune development markers IL-6 and IL-1ß in a peripheral blood mononuclear cell (PBMC) model. Finally, the safety of BG-L47 was evaluated both by genome safety assessment and in a human safety study. Microbiota analysis showed that the treatment did not induce significant changes in the composition. In conclusion, B. longum subsp. longum BG-L47 has favorable physiological properties, can boost the in vitro activity of L. reuteri DSM 17938, and is safe for consumption, making it a candidate for further evaluation in probiotic studies. IMPORTANCE By using probiotics that contain a combination of strains with synergistic properties, the likelihood of achieving beneficial interactions with the host can increase. In this study, we first performed a broad screening of Bifidobacterium longum subsp. longum strains in terms of synergistic potential and physiological properties. We identified a superior strain, BG-L47, with favorable characteristics and potential to boost the activity of the known probiotic strain Limosilactobacillus reuteri DSM 17938. Furthermore, we demonstrated that BG-L47 is safe for consumption in a human randomized clinical study and by performing a genome safety assessment. This work illustrates that bacteria-bacteria interactions differ at the strain level and further provides a strategy for finding and selecting companion strains of probiotics.
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Affiliation(s)
- Ludwig Ermann Lundberg
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences, Uppsala, Sweden
- BioGaia, Stockholm, Sweden
| | - Punya Pallabi Mishra
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | | | - Manuel Mata Forsberg
- The Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Eva Sverremark-Ekström
- The Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | | | - Sebastian Håkansson
- BioGaia, Stockholm, Sweden
- Division of Applied Microbiology, Department of Chemistry, Lund University, Lund, Sweden
| | - Caroline Linninge
- BioGaia, Stockholm, Sweden
- Department of Food Technology, Engineering and Nutrition, Lund University, Lund, Sweden
| | - Stefan Roos
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences, Uppsala, Sweden
- BioGaia, Stockholm, Sweden
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Aleksic B, Udovicki B, Kovacevic J, Miloradovic Z, Djekic I, Miocinovic J, Tomic N, Smigic N. Microbiological Assessment of Dairy Products Produced by Small-Scale Dairy Producers in Serbia. Foods 2024; 13:1456. [PMID: 38790756 PMCID: PMC11119881 DOI: 10.3390/foods13101456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2024] [Revised: 04/29/2024] [Accepted: 05/07/2024] [Indexed: 05/26/2024] Open
Abstract
The microbiological quality of dairy products from small-scale producers in Serbia was analysed. A total of 302 dairy products [raw (n = 111) and pasteurized milk cheeses (n = 79) and kajmak (n = 112)], were collected and tested for the presence of pathogens, Listeria monocytogenes and Salmonella spp., and enumerated for Coagulase-positive staphylococci (CPS), Escherichia coli, and yeasts and moulds. None of the samples tested positive for Salmonella spp., while L. monocytogenes was recovered from one raw milk cheese and five kajmak samples. Raw milk cheese and kajmak also had higher levels of indicator microorganisms, namely E. coli and yeast and moulds. Molecular serotyping grouped L. monocytogenes isolates into serogroups 1 (1/2a and 3a) and 3 (1/2b, 3b, and 7). When exposed to eight antibiotics, L. monocytogenes isolates were mostly sensitive, with the exception of oxacillin and reduced susceptibility to clindamycin, penicillin G, and trimethoprim/sulfamethoxazole, emphasizing the importance of continuous surveillance for antimicrobial resistance. Samples that tested positive for Listeria spp. also had higher loads of indicator microorganisms, namely E. coli and yeast and moulds, suggesting lapses in hygiene practices during production. Collectively, these data emphasize the need for improved food safety and hygiene practices among small-scale dairy producers. This is crucial to reduce the microbial contamination and improve both the quality and safety of dairy products in the Serbian market.
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Affiliation(s)
- Biljana Aleksic
- Department of Food Safety and Quality Management, Faculty of Agriculture, University of Belgrade, Nemanjina 6, 11080 Belgrade, Serbia; (B.A.); (B.U.); (I.D.); (N.T.)
- Dairy Institute, Smolucska 11, 11070 Belgrade, Serbia
| | - Bozidar Udovicki
- Department of Food Safety and Quality Management, Faculty of Agriculture, University of Belgrade, Nemanjina 6, 11080 Belgrade, Serbia; (B.A.); (B.U.); (I.D.); (N.T.)
| | - Jovana Kovacevic
- Food Innovation Center, Oregon State University, 1207 NW Naito Parkway, Portland, OR 97209, USA;
| | - Zorana Miloradovic
- Department of Animal Source Food Technology, Faculty of Agriculture, University of Belgrade, Nemanjina 6, 11080 Belgrade, Serbia; (Z.M.); (J.M.)
| | - Ilija Djekic
- Department of Food Safety and Quality Management, Faculty of Agriculture, University of Belgrade, Nemanjina 6, 11080 Belgrade, Serbia; (B.A.); (B.U.); (I.D.); (N.T.)
| | - Jelena Miocinovic
- Department of Animal Source Food Technology, Faculty of Agriculture, University of Belgrade, Nemanjina 6, 11080 Belgrade, Serbia; (Z.M.); (J.M.)
| | - Nikola Tomic
- Department of Food Safety and Quality Management, Faculty of Agriculture, University of Belgrade, Nemanjina 6, 11080 Belgrade, Serbia; (B.A.); (B.U.); (I.D.); (N.T.)
| | - Nada Smigic
- Department of Food Safety and Quality Management, Faculty of Agriculture, University of Belgrade, Nemanjina 6, 11080 Belgrade, Serbia; (B.A.); (B.U.); (I.D.); (N.T.)
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Glass KA, Lim JY, Singer QL. Inactivation of Listeria monocytogenes by Hydrogen Peroxide Addition in Commercial Cheese Brines. J Food Prot 2024; 87:100191. [PMID: 37949411 DOI: 10.1016/j.jfp.2023.100191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 10/31/2023] [Accepted: 11/03/2023] [Indexed: 11/12/2023]
Abstract
Commercial cheese brines are used repeatedly over extended periods, potentially for years, and can be a reservoir for salt-tolerant pathogens, such as Listeria monocytogenes. The objective of this study was to determine the inactivation of L. monocytogenes in cheese brines treated with hydrogen peroxide (H2O2) (0, 50, and 100 ppm) at holding temperatures representing manufacturing conditions. In experiment one, four fresh cheese brines were prepared with 10 or 20% salt and pH 4.6 or 5.4 (2x2 design; duplicate trials). Brines were inoculated with L. monocytogenes, treated with H2O2, and stored at 10 and 15.6°C. For experiment two, seven used commercial brines (representing five cheese types, 15-30% NaCl, pH 4.5-5.5; three seasonal trials) were inoculated with L. monocytogenes or S. aureus, treated with H2O2, and stored at 12.8°C (both L. monocytogenes and S. aureus), 7.2 and 0°C (L. monocytogenes only). Each treatment was assayed on Days 0, 1, and 7 for microbial populations and residual H2O2. Data revealed that pathogen populations decreased ≤1 log in cheese brines with no hydrogen peroxide stored for 7 days, regardless of the storage temperature. In fresh brine treated with 50 or 100 ppm of H2O2, populations of L. monocytogenes were reduced to less than the detectable limit by 7 days at 10 and 15.6°C (>4 log reduction). For unfiltered used brines, H2O2 had no effect on L. monocytogenes populations in Brick J (pH 5.4, 15% NaCl) due to rapid inactivation of H2O2, likely by indigenous yeasts (∼3-log CFU/ml). For the remaining brines, the addition of 100 ppm H2O2 killed >4 log L. monocytogenes when stored at 7.2 or 12.8°C for 1 week, but only 3-4 log reduction when stored at 0°C. The addition of 50 ppm H2O2 had similar lethal effects at 12.8°C but was less effective at 7.2 or 0°C. Inactivation rates of S. aureus were similar to that of L. monocytogenes. This study confirmed that high salt, warmer temperature, and 100-ppm H2O2 accelerated the inactivation of L. monocytogenes in cheese brines. Data also suggest that the presence of catalase-positive indigenous microorganisms may neutralize the effect of H2O2.
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Affiliation(s)
- Kathleen A Glass
- Food Research Institute, University of Wisconsin-Madison, 1550 Linden Drive, WI 53705, USA.
| | - Jie Yin Lim
- Food Research Institute, University of Wisconsin-Madison, 1550 Linden Drive, WI 53705, USA
| | - Quinn L Singer
- Food Research Institute, University of Wisconsin-Madison, 1550 Linden Drive, WI 53705, USA
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Primavilla S, Roila R, Rocchegiani E, Blasi G, Petruzzelli A, Gabucci C, Ottaviani D, Di Lullo S, Branciari R, Ranucci D, Valiani A. Assessment of the Microbiological Safety and Hygiene of Raw and Thermally Treated Milk Cheeses Marketed in Central Italy between 2013 and 2020. Life (Basel) 2023; 13:2324. [PMID: 38137925 PMCID: PMC10744727 DOI: 10.3390/life13122324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 11/29/2023] [Accepted: 12/09/2023] [Indexed: 12/24/2023] Open
Abstract
A profile of the microbial safety and hygiene of cheese in central Italy was defined based on an analysis of 1373 cheeses sampled under the Italian National Control Plan for Food Safety spanning the years 2013 to 2020 and tested according to Commission Regulation (EC) No. 2073/2005 (as amended). A total of 97.4% of cheese samples were assessed as being satisfactory for food safety criteria and 80.5% for process hygiene criteria. Staphylococcal enterotoxin was found in 2/414 samples, while Salmonella spp. and Listeria monocytogenes were detected in 15 samples out of 373 and 437, respectively. Escherichia coli and coagulase-positive staphylococci counts were found unsatisfactory in 12/61 and 17/88 cheese samples, respectively. The impact of milking species, milk thermal treatment, and cheese hardness category was considered. A statistically significant association (p < 0.05) was found between milk thermal treatment and the prevalence of coagulase-positive staphylococci and Listeria monocytogenes and between hardness and unsatisfactory levels of Escherichia coli. The data depict a contained public health risk associated with these products and confirm, at the same time, the importance of strict compliance with good hygiene practices during milk and cheese production. These results can assist in bolstering risk analysis and providing insights for food safety decision making.
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Affiliation(s)
- Sara Primavilla
- Istituto Zooprofilattico Sperimentale dell’Umbria e delle Marche “Togo Rosati”, Via Salvemini 1, 06126 Perugia, Italy; (S.P.); (E.R.); (G.B.); (A.P.); (C.G.); (D.O.); (S.D.L.); (A.V.)
| | - Rossana Roila
- Department of Veterinary Medicine, University of Perugia, Via San Costanzo 4, 06126 Perugia, Italy; (R.B.); (D.R.)
| | - Elena Rocchegiani
- Istituto Zooprofilattico Sperimentale dell’Umbria e delle Marche “Togo Rosati”, Via Salvemini 1, 06126 Perugia, Italy; (S.P.); (E.R.); (G.B.); (A.P.); (C.G.); (D.O.); (S.D.L.); (A.V.)
| | - Giuliana Blasi
- Istituto Zooprofilattico Sperimentale dell’Umbria e delle Marche “Togo Rosati”, Via Salvemini 1, 06126 Perugia, Italy; (S.P.); (E.R.); (G.B.); (A.P.); (C.G.); (D.O.); (S.D.L.); (A.V.)
| | - Annalisa Petruzzelli
- Istituto Zooprofilattico Sperimentale dell’Umbria e delle Marche “Togo Rosati”, Via Salvemini 1, 06126 Perugia, Italy; (S.P.); (E.R.); (G.B.); (A.P.); (C.G.); (D.O.); (S.D.L.); (A.V.)
| | - Claudia Gabucci
- Istituto Zooprofilattico Sperimentale dell’Umbria e delle Marche “Togo Rosati”, Via Salvemini 1, 06126 Perugia, Italy; (S.P.); (E.R.); (G.B.); (A.P.); (C.G.); (D.O.); (S.D.L.); (A.V.)
| | - Donatella Ottaviani
- Istituto Zooprofilattico Sperimentale dell’Umbria e delle Marche “Togo Rosati”, Via Salvemini 1, 06126 Perugia, Italy; (S.P.); (E.R.); (G.B.); (A.P.); (C.G.); (D.O.); (S.D.L.); (A.V.)
| | - Stefania Di Lullo
- Istituto Zooprofilattico Sperimentale dell’Umbria e delle Marche “Togo Rosati”, Via Salvemini 1, 06126 Perugia, Italy; (S.P.); (E.R.); (G.B.); (A.P.); (C.G.); (D.O.); (S.D.L.); (A.V.)
| | - Raffaella Branciari
- Department of Veterinary Medicine, University of Perugia, Via San Costanzo 4, 06126 Perugia, Italy; (R.B.); (D.R.)
| | - David Ranucci
- Department of Veterinary Medicine, University of Perugia, Via San Costanzo 4, 06126 Perugia, Italy; (R.B.); (D.R.)
| | - Andrea Valiani
- Istituto Zooprofilattico Sperimentale dell’Umbria e delle Marche “Togo Rosati”, Via Salvemini 1, 06126 Perugia, Italy; (S.P.); (E.R.); (G.B.); (A.P.); (C.G.); (D.O.); (S.D.L.); (A.V.)
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Giagnoni L, Deb S, Tondello A, Zardinoni G, De Noni M, Franchin C, Vanzin A, Arrigoni G, Masi A, Stevanato P, Cecchinato A, Squartini A, Spanu C. The impact of milk storage temperatures on cheese quality and microbial communities at dairy processing plant scale. Food Res Int 2023; 172:113101. [PMID: 37689865 DOI: 10.1016/j.foodres.2023.113101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 05/11/2023] [Accepted: 06/09/2023] [Indexed: 09/11/2023]
Abstract
Cheese production is an applied biotechnology whose proper outcome relies strictly on the complex interactive dynamics which unfold within defined microbial groups. These may start being active from the collection of milk and continue up to its final stages of maturation. One of the critical parameters playing a major role is the milk refrigeration temperature before pasteurization as it can affect the proportion of psychrotrophic taxa abundance in the total milk bacterial population. While a standard temperature of 4 °C is the common choice, due to its general growth control effect, it does have a potential drawback. This is due to the fact that some cold-tolerant genera present a proteolytic activity with uncompleted proliferation, which could negatively affect curd clotting and regular cheese maturation. Moreover, accidental thermal variations of milk before cheese-making, in a plus or minus direction, can occur both at farm collection sites and during transfer to dairy plant. This present research, directly commissioned by a major fresh cheese-producing company, includes an in-factory trial. In this trial, a gradient of temperatures from 4 °C to 13 °C, which were subsequently reversed, was purposely adopted to: (a) verify sensory alterations in the resulting product at different maturation stages, and, (b) analyze, in parallel, using DNA extraction and 16S-metabarcoding sequencing from the same samples, the presence, abundance and corresponding taxonomical identity of all the bacteria featured in communities found in milk and cheese samples. Overall, 1,714 different variants were detected and sorted into 394 identified taxa. Significant bacterial community shifts in cheese were observed in response to milk refrigeration temperature and subsequently associated with samples having altered scores in sensory panel tests. In particular, proteolytic psychrotrophes were outcompeted by Enterobacteriales and by other taxa at the peak temperature of 13 °C, but aggressively increased in the descent phases, upon the cooling down of milk to values of 7 °C. Relevant clues have been collected for better anticipation of thermal abuse effects or parameter variations allowing for improved handling of technical processing conditions by the cheese manufacturing industry.
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Affiliation(s)
- Lucia Giagnoni
- Department of Veterinary Medicine, University of Sassari, Via Vienna, 2, 07100 Sassari (SS), Italy; Department of Agronomy, Food, Natural Resources, Animals and Environment, DAFNAE, University of Padova, Viale dell'Università 16, 35020 Legnaro, (PD), Italy.
| | - Saptarathi Deb
- Department of Agronomy, Food, Natural Resources, Animals and Environment, DAFNAE, University of Padova, Viale dell'Università 16, 35020 Legnaro, (PD), Italy
| | - Alessandra Tondello
- Department of Agronomy, Food, Natural Resources, Animals and Environment, DAFNAE, University of Padova, Viale dell'Università 16, 35020 Legnaro, (PD), Italy
| | - Giulia Zardinoni
- Department of Agronomy, Food, Natural Resources, Animals and Environment, DAFNAE, University of Padova, Viale dell'Università 16, 35020 Legnaro, (PD), Italy
| | - Michele De Noni
- Latteria Montello S.p.A. Via Fante d'Italia 26, 31040 Giavera del Montello (TV), Italy
| | - Cinzia Franchin
- Department of Agronomy, Food, Natural Resources, Animals and Environment, DAFNAE, University of Padova, Viale dell'Università 16, 35020 Legnaro, (PD), Italy
| | - Alice Vanzin
- Department of Agronomy, Food, Natural Resources, Animals and Environment, DAFNAE, University of Padova, Viale dell'Università 16, 35020 Legnaro, (PD), Italy
| | - Giorgio Arrigoni
- Department of Biomedical Sciences, University of Padova, Via Ugo Bassi 587b, 35131 Padova (PD), Italy
| | - Antonio Masi
- Department of Agronomy, Food, Natural Resources, Animals and Environment, DAFNAE, University of Padova, Viale dell'Università 16, 35020 Legnaro, (PD), Italy
| | - Piergiorgio Stevanato
- Department of Agronomy, Food, Natural Resources, Animals and Environment, DAFNAE, University of Padova, Viale dell'Università 16, 35020 Legnaro, (PD), Italy
| | - Alessio Cecchinato
- Department of Agronomy, Food, Natural Resources, Animals and Environment, DAFNAE, University of Padova, Viale dell'Università 16, 35020 Legnaro, (PD), Italy
| | - Andrea Squartini
- Department of Agronomy, Food, Natural Resources, Animals and Environment, DAFNAE, University of Padova, Viale dell'Università 16, 35020 Legnaro, (PD), Italy
| | - Carlo Spanu
- Department of Veterinary Medicine, University of Sassari, Via Vienna, 2, 07100 Sassari (SS), Italy
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Silva BN, Coelho-Fernandes S, Teixeira JA, Cadavez V, Gonzales-Barron U. Dynamic Modelling to Describe the Effect of Plant Extracts and Customised Starter Culture on Staphylococcus aureus Survival in Goat's Raw Milk Soft Cheese. Foods 2023; 12:2683. [PMID: 37509778 PMCID: PMC10379104 DOI: 10.3390/foods12142683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 07/06/2023] [Accepted: 07/07/2023] [Indexed: 07/30/2023] Open
Abstract
This study characterises the effect of a customised starter culture (CSC) and plant extracts (lemon balm, sage, and spearmint) on Staphylococcus aureus (SA) and lactic acid bacteria (LAB) kinetics in goat's raw milk soft cheeses. Raw milk cheeses were produced with and without the CSC and plant extracts, and analysed for pH, SA, and LAB counts throughout ripening. The pH change over maturation was described by an empirical decay function. To assess the effect of each bio-preservative on SA, dynamic Bigelow-type models were adjusted, while their effect on LAB was evaluated by classical Huang models and dynamic Huang-Cardinal models. The models showed that the bio-preservatives decreased the time necessary for a one-log reduction but generally affected the cheese pH drop and SA decay rates (logDref = 0.621-1.190 days; controls: 0.796-0.996 days). Spearmint and sage extracts affected the LAB specific growth rate (0.503 and 1.749 ln CFU/g day-1; corresponding controls: 1.421 and 0.806 ln CFU/g day-1), while lemon balm showed no impact (p > 0.05). The Huang-Cardinal models uncovered different optimum specific growth rates of indigenous LAB (1.560-1.705 ln CFU/g day-1) and LAB of cheeses with CSC (0.979-1.198 ln CFU/g day-1). The models produced validate the potential of the tested bio-preservatives to reduce SA, while identifying the impact of such strategies on the fermentation process.
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Affiliation(s)
- Beatriz Nunes Silva
- Centro de Investigação de Montanha (CIMO), Instituto Politécnico de Bragança, Campus de Santa Apolónia, 5300-253 Bragança, Portugal
- Laboratório para a Sustentabilidade e Tecnologia em Regiões de Montanha, Instituto Politécnico de Bragança, Campus de Santa Apolónia, 5300-253 Bragança, Portugal
- CEB-Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal
| | - Sara Coelho-Fernandes
- Centro de Investigação de Montanha (CIMO), Instituto Politécnico de Bragança, Campus de Santa Apolónia, 5300-253 Bragança, Portugal
- Laboratório para a Sustentabilidade e Tecnologia em Regiões de Montanha, Instituto Politécnico de Bragança, Campus de Santa Apolónia, 5300-253 Bragança, Portugal
| | - José António Teixeira
- CEB-Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal
- LABBELS-Associate Laboratory, 4710-057 Braga, Portugal
| | - Vasco Cadavez
- Centro de Investigação de Montanha (CIMO), Instituto Politécnico de Bragança, Campus de Santa Apolónia, 5300-253 Bragança, Portugal
- Laboratório para a Sustentabilidade e Tecnologia em Regiões de Montanha, Instituto Politécnico de Bragança, Campus de Santa Apolónia, 5300-253 Bragança, Portugal
| | - Ursula Gonzales-Barron
- Centro de Investigação de Montanha (CIMO), Instituto Politécnico de Bragança, Campus de Santa Apolónia, 5300-253 Bragança, Portugal
- Laboratório para a Sustentabilidade e Tecnologia em Regiões de Montanha, Instituto Politécnico de Bragança, Campus de Santa Apolónia, 5300-253 Bragança, Portugal
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Listeria monocytogenes, Escherichia coli and Coagulase Positive Staphylococci in Cured Raw Milk Cheese from Alentejo Region, Portugal. Microorganisms 2023; 11:microorganisms11020322. [PMID: 36838288 PMCID: PMC9964920 DOI: 10.3390/microorganisms11020322] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 01/24/2023] [Accepted: 01/25/2023] [Indexed: 01/31/2023] Open
Abstract
Traditional cheeses are part of the Portuguese gastronomic identity, and raw milk of autochthonous species is a common primary ingredient. Here, we investigated the presence of Listeria monocytogenes, Coagulase Positive Staphylococci (CPS) and pathogenic Escherichia coli, as well as of indicator microorganisms (E. coli and other Listeria spp.) in 96 cured raw milk cheeses from the Alentejo region. Whole genome sequencing (WGS) of pathogenic E. coli and Listeria spp. as well as antimicrobial resistance (AMR) screening of E. coli isolates was also performed. L. monocytogenes, CPS > 104 cfu/g and Extraintestinal E. coli were detected in 15.6%, 16.9% and 10.1% of the samples, respectively. Moreover, L. monocytogenes > 102 cfu/g and Staphylococcal enterotoxins were detected in 4.2% and 2.2% of the samples, respectively. AMR was observed in 27.3% of the E. coli isolates, six of which were multidrug resistant. WGS analysis unveiled clusters of high closely related isolates for both L. monocytogenes and L. innocua (often correlating with the cheese producer). This study can indicate poor hygiene practices during milk collection/preservation or during cheese-making procedures and handling, and highlights the need of more effective prevention and control measures and of multi-sectoral WGS data integration, in order to prevent and detect foodborne bacterial outbreaks.
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Sakaridis I, Psomas E, Karatzia MA, Samouris G. Hygiene and Safety of Hard Cheese Made from Raw Cows' Milk. Vet Sci 2022; 9:vetsci9100569. [PMID: 36288182 PMCID: PMC9609050 DOI: 10.3390/vetsci9100569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 08/22/2022] [Accepted: 10/12/2022] [Indexed: 11/05/2022] Open
Abstract
Simple Summary Raw cheeses have gained the preference of some consumers because of their intense and stronger taste compared with that of pasteurised cheeses. The pasteurization of raw milk causes the inactivation of the pathogenic and beneficial microorganisms of milk and of enzymes such as proteases and lipases which play a significant role in enhancing the unique flavour of raw cheeses. This study was conducted to evaluate the microbiological status of cheese made from unpasteurized cows’ milk, to examine the safety of the cheese and to observe the changes that occurred in its microbial community during ripening and storage. The microbiological quality of raw milk was found generally good and was improved throughout the experiments. For the cheese samples, a small increase in the prevalence of indicator microorganisms in curd and cheese samples was observed for the first few days, followed by a relatively stable condition as manufacturing proceeded and throughout the ripening of the final product. The outcome of our study was that the use of good-quality raw milk under sanitary conditions, the application of good manufacturing practices and a maturation period in a controlled environment were found to be the necessary prerequisites for the production of safe raw cheese products. Abstract This study was conducted to evaluate the microbiological status of cheese made from unpasteurized cows’ milk, to examine the safety of the cheese and to observe the changes that occurred in its microbial community during ripening and storage. Furthermore, the pH, the moisture and salt concentration were also monitored throughout processing, ripening and storage. Seven cheesemaking trials took place along with the microbiological and physicochemical analysis of the milk, curd and cheese produced. The milk used for the cheesemaking, two curd samples before the heating and two after the heating, two cheese samples at days 3, 7, 15, 30, 60 and 90 were subjected to microbiological analysis for total mesophilic bacterial count (for milk only), Enterobacteriaceae, E. coli, Staphylococcus, Salmonella, Listeria, and Clostridium. The microbiological quality of raw milk was found to be good. It was initially slightly above the EU limit but improvements associated with farm biosecurity and milking equipment hygiene led to a significantly improved milk quality. A small increase in the prevalence of indicator microorganisms in curd and cheese samples was observed for the first few days, followed by a relatively stable condition as manufacturing proceeded and throughout the ripening of the final product. In two cheesemaking trials, Clostridium perfringens and Salmonella spp. were detected, the first originating from the milk and the second from the environment. The use of good-quality raw milk under sanitary conditions, the application of good manufacturing practices and a maturation period in a controlled environment were found to be the necessary prerequisites for the production of safe raw cheese products.
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Affiliation(s)
- Ioannis Sakaridis
- Department of Hygiene and Technology of Food of Animal Origin, Veterinary Research Institute, Hellenic Agricultural Organization-Demeter, Campus of Thermi, 57001 Thessaloniki, Greece
- Correspondence:
| | - Evdoxios Psomas
- Department of Hygiene and Technology of Food of Animal Origin, Veterinary Research Institute, Hellenic Agricultural Organization-Demeter, Campus of Thermi, 57001 Thessaloniki, Greece
| | - Maria-Anastasia Karatzia
- Research Institute of Animal Science, Hellenic Agricultural Organization-Demeter, 58100 Giannitsa, Greece
| | - Georgios Samouris
- Department of Hygiene and Technology of Food of Animal Origin, Veterinary Research Institute, Hellenic Agricultural Organization-Demeter, Campus of Thermi, 57001 Thessaloniki, Greece
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10
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Prevalence and Genetic Diversity of Coagulase Negative Staphylococcus in Food Products Collected from Riyadh Region. JOURNAL OF PURE AND APPLIED MICROBIOLOGY 2021. [DOI: 10.22207/jpam.15.4.20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The goal of this study was to isolate, count, and identify coagulase-negative Staphylococci from meat and dairy products collected in Riyadh, Saudi Arabia, as well as to perform molecular identification of the mecA gene. In addition, the prevalence of these bacteria among the examined food products was determined. Ninety samples of both meat and dairy products were collected and examined between February 2018 and August 2019. Mannitol salt agar and VITEK 2 system were carried out and VITEK 2 system was used to identify all bacterial isolates. Also, the molecular technique was used to detect the target gene of mecA among CoNS. The proportion of samples in which Staphylococcus species isolated is 13.33% (Camel meat), 6.66% (Beef mortadella), 6.66% (Turkish labneh), 33.33% (Cows cheese), 6.66% (Goat labneh), 13.33% (Nabulsy cheese), 13.33% (Haloumi goat cheese) and 6.66% (Akawy white cheese). Counts of coagulase-negative Staphylococcus species (as cfu/gm) of sample were around 11×104, 10×104, 9×104, 12×104, 4×105, 11×104 (Nabulsy cheese), 14×104 and 12×104, respectively. The Prevalence of species in both products was 3.30% (Staphylococcus vitulinus), 53.30% (Staphylococcus saprophyticus), 16.66% (Staphylococcus hominis), 6.66%, (Staphylococcus equorum and Staphylococcus lentus) and 13.33% (Staphylococcus sciuri). Furthermore, results showed methicillin specific mecA gene was harbored in 40 % of the CoNS.
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11
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Morar A, Ban-Cucerzan A, Herman V, Tîrziu E, Sallam KI, Abd-Elghany SM, Imre K. Multidrug Resistant Coagulase-Positive Staphylococcus aureus and Their Enterotoxins Detection in Traditional Cheeses Marketed in Banat Region, Romania. Antibiotics (Basel) 2021; 10:antibiotics10121458. [PMID: 34943670 PMCID: PMC8698683 DOI: 10.3390/antibiotics10121458] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 11/24/2021] [Accepted: 11/25/2021] [Indexed: 11/16/2022] Open
Abstract
The main objectives of the present study were to determine the occurrence of coagulase positive staphylococci (CPS) and to assess the presence and antimicrobial susceptibility profile of Staphylococcus aureus isolates in different raw milk origin (cow and sheep) traditional cheeses marketed in Banat region, Romania. Additionally, the presence of mecA gene in S. aureus isolates and the staphylococcal enterotoxins (SEs) in cheese samples were evaluated. A total of 81.6% (138/169) of the screened samples were positive for CPS. Furthermore, 35.5% (49/138) of the investigated CPS positive cheese samples were contaminated with S. aureus, with an isolation frequency of 46.6% (14/30) in caș, 33.3% (32/96) in telemea, 25% (2/8) in burduf, and 25% (1/4) in urdă assortments, respectively. From the total number of S. aureus isolates, 6.1% (3/49) harbored the mecA gene. Detectable levels of SEs were identified in 4.3% (4/94) of cheese samples with a CPS contamination level higher than 105 log CFU g−1. The expressed antimicrobial susceptibility profile of the tested cheese-origin S. aureus isolates, with the automated Vitek 2 equipment, showed resistance towards amikacin (90.1%, 10 out from 11 tested), enrofloxacin (86.2%, 25/29), ceftiofur (72.7%, 8/11), neomycin (63.6%, 7/11), benzylpenicillin (53.1%, 26/49), kanamycin (41.4%, 12/29), rifampicin (39.5%, 15/38), tetracycline (38.8%, 19/49), tilmicosin (36.4%, 4/11), clindamycin (30.6%, 15/49), ciprofloxacin (30%, 6/20), erythromycin (22.4%, 11/49), tylosin (18.2%, 2/11), oxacillin (16.3%, 8/49), linezolid (15%, 3/20), teicoplanin (15%, 3/20), fusidic acid (13.1%), imipenem (10.5%, 4/38), vancomycin (7.9%, 3/38), ampicillin (5.5%, 1/18), mupirocin (5.5%, 1/18), fosfomycin (5%, 1/20), and gentamicin (4.1%, 2/49). Twenty-four (49%) S. aureus isolates exhibited multidrug resistance. The investigation highlighted a common occurrence of multidrug-resistant S. aureus strains in the monitored cheese assortments, which can constitute a potential risk for consumers’ health.
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Affiliation(s)
- Adriana Morar
- Department of Animal Production and Veterinary Public Health, Faculty of Veterinary Medicine, Banat’s University of Agricultural Sciences and Veterinary Medicine “King Michael I of Romania” from Timişoara, 300645 Timisoara, Romania; (A.M.); (A.B.-C.); (E.T.)
| | - Alexandra Ban-Cucerzan
- Department of Animal Production and Veterinary Public Health, Faculty of Veterinary Medicine, Banat’s University of Agricultural Sciences and Veterinary Medicine “King Michael I of Romania” from Timişoara, 300645 Timisoara, Romania; (A.M.); (A.B.-C.); (E.T.)
| | - Viorel Herman
- Department of Infectious Diseases and Preventive Medicine, Faculty of Veterinary Medicine, Banat’s University of Agricultural Sciences and Veterinary Medicine “King Michael I of Romania” from Timişoara, 300645 Timisoara, Romania;
| | - Emil Tîrziu
- Department of Animal Production and Veterinary Public Health, Faculty of Veterinary Medicine, Banat’s University of Agricultural Sciences and Veterinary Medicine “King Michael I of Romania” from Timişoara, 300645 Timisoara, Romania; (A.M.); (A.B.-C.); (E.T.)
| | - Khalid Ibrahim Sallam
- Department of Food Hygiene and Control, Faculty of Veterinary Medicine, Mansoura University, Mansoura 35511, Egypt; (K.I.S.); (S.M.A.-E.)
| | - Samir Mohammed Abd-Elghany
- Department of Food Hygiene and Control, Faculty of Veterinary Medicine, Mansoura University, Mansoura 35511, Egypt; (K.I.S.); (S.M.A.-E.)
| | - Kálmán Imre
- Department of Animal Production and Veterinary Public Health, Faculty of Veterinary Medicine, Banat’s University of Agricultural Sciences and Veterinary Medicine “King Michael I of Romania” from Timişoara, 300645 Timisoara, Romania; (A.M.); (A.B.-C.); (E.T.)
- Correspondence:
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12
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Jaramillo-Bedoya E, Trujillo-Alzate YA, Ocampo-Ibáñez ID. Surveillance of Fresh Artisanal Cheeses Revealed High Levels of Listeria monocytogenes Contamination in the Department of Quindío, Colombia. Pathogens 2021; 10:pathogens10101341. [PMID: 34684290 PMCID: PMC8537478 DOI: 10.3390/pathogens10101341] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Revised: 10/12/2021] [Accepted: 10/13/2021] [Indexed: 11/16/2022] Open
Abstract
Listeriosis is a foodborne disease caused by Listeria monocytogenes. Because outbreaks of listeriosis are associated with the ingestion of contaminated dairy products, surveillance of artisanal cheeses to detect the presence of this microorganism is necessary. We collected three types of artisanal non-acid fresh cheese (Campesino, Costeño, and Cuajada) from 12 municipalities of the Department of Quindío, Colombia. L. monocytogenes was identified using VIDAS® and confirmed with API® Listeria Rapid Kit. L. monocytogenes was detected in 104 (53.6%) of the 194 artisanal fresh-cheese samples analyzed. The highest percentages of contamination were detected in Salento (90.9%), Calracá (65.5%), Armenia (64.9%), and Filandia (50%). A significant association between municipality and contamination with L. monocytogenes was identified. However, no association could be established between the type of cheese and the occurrence of the bacterium. This is the first study on the presence of L. monocytogenes in artisanal fresh cheeses sold in the municipalities of the Department of Quindío, and the findings revealed very high percentages of contaminated samples. The presence of L. monocytogenes in artisanal cheeses remains a public health threat in developing countries, especially Colombia, where existing legislation does not require the surveillance of L. monocytogenes in food.
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Affiliation(s)
- Elizabeth Jaramillo-Bedoya
- Laboratorio de Salud Pública Departamental, Secretaría de Salud Departamental del Quindío, Gobernación del Quindío, Armenia 630008, Colombia; (E.J.-B.); (Y.A.T.-A.)
| | - Yenny Alexandra Trujillo-Alzate
- Laboratorio de Salud Pública Departamental, Secretaría de Salud Departamental del Quindío, Gobernación del Quindío, Armenia 630008, Colombia; (E.J.-B.); (Y.A.T.-A.)
| | - Iván Darío Ocampo-Ibáñez
- Research Group of Microbiology, Industry and Environment (GIMIA), Faculty of Basic Sciences, Universidad Santiago de Cali, Cali 760035, Colombia
- Correspondence: ; Tel.: +57-518-3000
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13
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Etter D, Jenni C, Tasara T, Johler S. Mild Lactic Acid Stress Causes Strain-Dependent Reduction in SEC Protein Levels. Microorganisms 2021; 9:1014. [PMID: 34066749 PMCID: PMC8151770 DOI: 10.3390/microorganisms9051014] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 04/30/2021] [Accepted: 05/05/2021] [Indexed: 12/12/2022] Open
Abstract
Staphylococcal enterotoxin C (SEC) is a major cause of staphylococcal food poisoning in humans and plays a role in bovine mastitis. Staphylococcus aureus (S. aureus) benefits from a competitive growth advantage under stress conditions encountered in foods such as a low pH. Therefore, understanding the role of stressors such as lactic acid on SEC production is of pivotal relevance to food safety. However, stress-dependent cues and their effects on enterotoxin expression are still poorly understood. In this study, we used human and animal strains harboring different SEC variants in order to evaluate the influence of mild lactic acid stress (pH 6.0) on SEC expression both on transcriptional and translational level. Although only a modest decrease in sec mRNA levels was observed under lactic acid stress, protein levels showed a significant decrease in SEC levels for some strains. These findings indicate that post-transcriptional modifications can act in SEC expression under lactic acid stress.
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Affiliation(s)
- Danai Etter
- Institute for Food Safety and Hygiene, University of Zurich, 8057 Zurich, Switzerland; (D.E.); (T.T.)
- Laboratory of Food Microbiology, Institute for Food, Nutrition and Health (IFNH), ETH Zurich, 8092 Zurich, Switzerland;
| | - Céline Jenni
- Laboratory of Food Microbiology, Institute for Food, Nutrition and Health (IFNH), ETH Zurich, 8092 Zurich, Switzerland;
| | - Taurai Tasara
- Institute for Food Safety and Hygiene, University of Zurich, 8057 Zurich, Switzerland; (D.E.); (T.T.)
| | - Sophia Johler
- Institute for Food Safety and Hygiene, University of Zurich, 8057 Zurich, Switzerland; (D.E.); (T.T.)
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14
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Prevalence and characteristics of Staphylococcus aureus isolated from Kazak cheese in Xinjiang, China. Food Control 2021. [DOI: 10.1016/j.foodcont.2020.107759] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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15
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Carvalho LG, Alvim MMA, Fabri RL, Apolônio ACM. Staphylococcus aureus
biofilm formation in Minas Frescal cheese packaging. INT J DAIRY TECHNOL 2021. [DOI: 10.1111/1471-0307.12783] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Lucas Guzella Carvalho
- Department of Parasitology, Microbiology and Immunology Institute of Biological Sciences Federal University of Juiz de Fora Juiz de Fora MG CEP 36036‐900 Brazil
| | - Mariana Massi Afonso Alvim
- Department of Parasitology, Microbiology and Immunology Institute of Biological Sciences Federal University of Juiz de Fora Juiz de Fora MG CEP 36036‐900 Brazil
| | - Rodrigo Luiz Fabri
- Bioactive Natural Products Laboratory Department of Biochemistry Institute of Biological Sciences Federal University of Juiz de Fora Juiz de Fora MG CEP 36036‐900 Brazil
| | - Ana Carolina Morais Apolônio
- Department of Parasitology, Microbiology and Immunology Institute of Biological Sciences Federal University of Juiz de Fora Juiz de Fora MG CEP 36036‐900 Brazil
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16
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Mayo B, Rodríguez J, Vázquez L, Flórez AB. Microbial Interactions within the Cheese Ecosystem and Their Application to Improve Quality and Safety. Foods 2021; 10:602. [PMID: 33809159 PMCID: PMC8000492 DOI: 10.3390/foods10030602] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 03/09/2021] [Indexed: 12/26/2022] Open
Abstract
The cheese microbiota comprises a consortium of prokaryotic, eukaryotic and viral populations, among which lactic acid bacteria (LAB) are majority components with a prominent role during manufacturing and ripening. The assortment, numbers and proportions of LAB and other microbial biotypes making up the microbiota of cheese are affected by a range of biotic and abiotic factors. Cooperative and competitive interactions between distinct members of the microbiota may occur, with rheological, organoleptic and safety implications for ripened cheese. However, the mechanistic details of these interactions, and their functional consequences, are largely unknown. Acquiring such knowledge is important if we are to predict when fermentations will be successful and understand the causes of technological failures. The experimental use of "synthetic" microbial communities might help throw light on the dynamics of different cheese microbiota components and the interplay between them. Although synthetic communities cannot reproduce entirely the natural microbial diversity in cheese, they could help reveal basic principles governing the interactions between microbial types and perhaps allow multi-species microbial communities to be developed as functional starters. By occupying the whole ecosystem taxonomically and functionally, microbiota-based cultures might be expected to be more resilient and efficient than conventional starters in the development of unique sensorial properties.
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Affiliation(s)
- Baltasar Mayo
- Departamento de Microbiología y Bioquímica, Instituto de Productos Lácteos de Asturias (IPLA), Consejo Superior de Investigaciones Científicas (CSIC), Paseo Río Linares s/n, 33300 Villaviciosa, Spain; (J.R.); (L.V.); (A.B.F.)
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17
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Kadri Z, Spitaels F, Cnockaert M, Amar M, Joossens M, Vandamme P. The bacterial diversity of raw Moroccon camel milk. Int J Food Microbiol 2021; 341:109050. [PMID: 33498008 DOI: 10.1016/j.ijfoodmicro.2021.109050] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 11/06/2020] [Accepted: 01/03/2021] [Indexed: 12/16/2022]
Abstract
Dromedary camel milk is generally considered a valuable and marketable commodity but its production suffers from poor hygienic conditions that result in low microbiological quality and the presence of various pathogens. The objective of the present study was to provide a detailed report of the bacterial species level composition of Moroccan raw camel milk samples that can serve as a starting point for the selection of starter cultures to facilitate a change in manufacturing practices to an improved and safer production system. The composition of the bacterial community in four freshly collected raw camel milk samples was analyzed by performing a large-scale isolation campaign combined with 16S rRNA gene amplicon sequencing. A total of 806 isolates were obtained from four raw camel milk samples using ten combinations of growth media and incubation conditions. Subsequent isolate dereplication using MALDI-TOF mass spectrometry and identification of representative isolates through sequence analysis of protein encoding and 16S rRNA genes revealed the presence of established and novel dairy lactic acid bacteria, as well as bacteria that are considered indicators of poor hygienic conditions and psychrotrophic spoilage organisms. The large numbers of Lactococcus and Enterococcus isolates obtained present an interesting resource for starter culture selection.
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Affiliation(s)
- Zaina Kadri
- Laboratory of Microbiology, Department of Biochemistry and Microbiology, Ghent University, K.L. Ledeganckstraat 35, 9000 Ghent, Belgium; Laboratoire de Microbiologie et Biologie Moléculaire, Centre National pour la Recherche Scientifique et Technique, Angle av. Allal El Fassi, av. des FAR, Quartier Hay Ryad, BP. 8027 Nations Unies, 10102 Rabat, Morocco
| | - Freek Spitaels
- Laboratory of Microbiology, Department of Biochemistry and Microbiology, Ghent University, K.L. Ledeganckstraat 35, 9000 Ghent, Belgium
| | - Margo Cnockaert
- Laboratory of Microbiology, Department of Biochemistry and Microbiology, Ghent University, K.L. Ledeganckstraat 35, 9000 Ghent, Belgium
| | - Mohamed Amar
- Laboratoire de Microbiologie et Biologie Moléculaire, Centre National pour la Recherche Scientifique et Technique, Angle av. Allal El Fassi, av. des FAR, Quartier Hay Ryad, BP. 8027 Nations Unies, 10102 Rabat, Morocco
| | - Marie Joossens
- Laboratory of Microbiology, Department of Biochemistry and Microbiology, Ghent University, K.L. Ledeganckstraat 35, 9000 Ghent, Belgium
| | - Peter Vandamme
- Laboratory of Microbiology, Department of Biochemistry and Microbiology, Ghent University, K.L. Ledeganckstraat 35, 9000 Ghent, Belgium.
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18
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Griffin S, Falzon O, Camilleri K, Valdramidis VP. Bacterial and fungal contaminants in caprine and ovine cheese: A meta-analysis assessment. Food Res Int 2020; 137:109445. [PMID: 33233125 DOI: 10.1016/j.foodres.2020.109445] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 06/08/2020] [Accepted: 06/12/2020] [Indexed: 10/24/2022]
Abstract
The dairy industry is of great importance to the European economy contributing towards € 8.7 billion of the total trade surplus. Caprine and ovine milk amount to 3.1% of the 152 million tonnes of milk produced in Europe, 95% of which is transformed into dairy products such as cheese. This cheese is mostly produced in small holdings from untreated milk, making it a high-risk dairy product for human consumption. A total of 49 foodborne disease outbreaks caused by dairy products were registered in 2017 in Europe. Therefore, these products remain a serious health risk. This meta-analysis examined 30 studies assessing bacterial or fungal contamination of caprine or ovine milk cheeses. The significantly contaminating microbes were found to be Acremonium spp. (19%), Aspergillus spp. (23%), Bacillus spp. (2%), Brucella spp. (34%), Enterobactericae spp. (36%), Enterococcus spp. (28%), Escherichia spp. (15%), Fusarium spp. (21%), Geotrichum spp. (22%), Listeria spp. (11%), Mucor spp. (15%), Penicillium spp. (25%), Phoma spp. (20%), Rhizopus spp. (15%), Salmonella spp. (3%), Scopulariopsis spp. (19%) and Staphylococcus spp. (25%) in caprine and ovine cheese, indicating a variety of food pathogens as well as spoilers. Raw milk is nutritious hence prone to contamination. However, since traditional cheese is often made from untreated milk, it is important to educate cheesemakers of key safety measures and good manufacturing practice allowing for the safe production of these food items.
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Affiliation(s)
- Sholeem Griffin
- Department of Food Sciences and Nutrition, University of Malta, Msida, Malta; Centre of Molecular Medicine and Biobanking, University of Malta, Msida, Malta; Centre for Biomedical Cybernetics, University of Malta, Msida, Malta.
| | - Owen Falzon
- Centre for Biomedical Cybernetics, University of Malta, Msida, Malta
| | - Kenneth Camilleri
- Systems & Control Engineering, Faculty of Engineering, University of Malta, Msida, Malta; Centre for Biomedical Cybernetics, University of Malta, Msida, Malta
| | - Vasilis P Valdramidis
- Department of Food Sciences and Nutrition, University of Malta, Msida, Malta; Centre of Molecular Medicine and Biobanking, University of Malta, Msida, Malta
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19
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Melo FD, Sfaciotte RAP, Dalmina KA, Wildemann P, Parussolo L, Wosiacki SR, Costa UMDA, Ferraz SM. Enterotoxigenic potential of Staphylococcus spp. isolates recovered from raw milk and artisanal cheese. AN ACAD BRAS CIENC 2020; 92:e20180925. [PMID: 33053101 DOI: 10.1590/0001-3765202020180925] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 12/21/2018] [Indexed: 11/21/2022] Open
Abstract
In this work, we investigated the phenotypic profile of Staphylococcus spp. isolates recovered from raw milk and artisanal cheese, and their enterotoxigenic potential through the detection of classical enterotoxin genes (sea, seb, sec, sed and see). A total of 104 isolates (58 coagulase-positive Staphylococcus - CoPS; and 46 coagulase-negative Staphylococcus- CoNS) were used, of which 33 were retrieved from raw milk and 71 from artisanal cheese produced in the Serrana region of Santa Catarina. Identification of CoPS was conducted via biochemical tests. Detection of the genes sea, seb, sec, sed, and see was carried out by multiplex PCR technique. Among the 58 CoPS analyzed, 64% were identified as S. aureus, 22% as S. scheiferi coagulans, 12% as S. hyicus and as 2% S. intermedius. In the present study was noted that 40% of CoPS isolates retrieved from milk harbored seb gene, while only one from artisanal cheese was positive for gene sea. In this study all CoNS samples investigated were negative for enterotoxins genes. The enterotoxigenic potential of CoPS, is an issue of great importance for public health. For that reason, it is necessary that cheese factories strictly follow the safety processes involved in manufacturing.
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Affiliation(s)
- Fernanda Danielle Melo
- Universidade do Estado de Santa Catarina/UDESC, Centro de Ciências Agroveterinárias, Avenida Luiz de Camões, 2090, Conta Dinheiro, 88520-000 Lages, SC, Brazil
| | - Ricardo Antonio P Sfaciotte
- Universidade do Estado de Santa Catarina/UDESC, Centro de Ciências Agroveterinárias, Avenida Luiz de Camões, 2090, Conta Dinheiro, 88520-000 Lages, SC, Brazil
| | - Karine Andrezza Dalmina
- Universidade do Estado de Santa Catarina/UDESC, Centro de Ciências Agroveterinárias, Avenida Luiz de Camões, 2090, Conta Dinheiro, 88520-000 Lages, SC, Brazil
| | - Paula Wildemann
- Universidade do Estado de Santa Catarina/UDESC, Centro de Ciências Agroveterinárias, Avenida Luiz de Camões, 2090, Conta Dinheiro, 88520-000 Lages, SC, Brazil
| | - Leandro Parussolo
- Instituto Federal de Santa Catarina/IFSC, Campus Florianópolis, Avenida Mauro Ramos, 950, Centro, 88020-300 Florianópolis, SC, Brazil
| | - Sheila R Wosiacki
- Universidade Estadual de Maringa/UEM, Estrada da Paca s/nº, São Cristóvão, 87502-970 Umuarama, PR, Brazil
| | - Ubirajara M DA Costa
- Universidade do Estado de Santa Catarina/UDESC, Centro de Ciências Agroveterinárias, Avenida Luiz de Camões, 2090, Conta Dinheiro, 88520-000 Lages, SC, Brazil
| | - Sandra Maria Ferraz
- Universidade do Estado de Santa Catarina/UDESC, Centro de Ciências Agroveterinárias, Avenida Luiz de Camões, 2090, Conta Dinheiro, 88520-000 Lages, SC, Brazil
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Etter D, Schelin J, Schuppler M, Johler S. Staphylococcal Enterotoxin C-An Update on SEC Variants, Their Structure and Properties, and Their Role in Foodborne Intoxications. Toxins (Basel) 2020; 12:E584. [PMID: 32927913 PMCID: PMC7551944 DOI: 10.3390/toxins12090584] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 09/07/2020] [Accepted: 09/08/2020] [Indexed: 12/20/2022] Open
Abstract
Staphylococcal enterotoxins are the most common cause of foodborne intoxications (staphylococcal food poisoning) and cause a wide range of diseases. With at least six variants staphylococcal enterotoxin C (SEC) stands out as particularly diverse amongst the 25 known staphylococcal enterotoxins. Some variants present unique and even host-specific features. Here, we review the role of SEC in human and animal health with a particular focus on its role as a causative agent for foodborne intoxications. We highlight structural features unique to SEC and its variants, particularly, the emetic and superantigen activity, as well as the roles of SEC in mastitis and in dairy products. Information about the genetic organization as well as regulatory mechanisms including the accessory gene regulator and food-related stressors are provided.
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Affiliation(s)
- Danai Etter
- Institute for Food Safety and Hygiene, Vetsuisse Faculty, University of Zürich, 8057 Zürich, Switzerland;
- Laboratory of Food Microbiology, Institute of Food, Nutrition and Health, ETH Zürich, 8092 Zürich, Switzerland;
| | - Jenny Schelin
- Division of Applied Microbiology, Department of Chemistry, Lund University, 22100 Lund, Sweden;
| | - Markus Schuppler
- Laboratory of Food Microbiology, Institute of Food, Nutrition and Health, ETH Zürich, 8092 Zürich, Switzerland;
| | - Sophia Johler
- Institute for Food Safety and Hygiene, Vetsuisse Faculty, University of Zürich, 8057 Zürich, Switzerland;
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21
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Occurrence and Characterization of Enterotoxigenic Staphylococci Isolated from Soft Cheeses in Serbia. ACTA VET-BEOGRAD 2020. [DOI: 10.2478/acve-2020-0017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Abstract
A total of 415 cheese samples produced with raw or cooked milk collected from local markets were analysed for the presence of coagulase-positive staphylococci. In 85 (20.48%) samples the presence of coagulase positive staphylococci was detected. The ELFA technique VIDAS SET2 (BioMerieux, France) was used for testing coagulase-positive staphylococci strains to produce classical enterotoxins (SEA, SEB, SEC, SED, SEE), and to determine the enterotoxins in cheese samples. The number of coagulase-positive staphylococci in cheese samples ranged from 1-5.79 log CFU g-1. Out of 85 coagulase-positive strains 26 (30.59%) produced enterotoxins. The presence of genes for the synthesis of staphylococcal enterotoxins (SE) in the obtained extracts of DNA from 26 enterotoxigenic strains was detected by conventional multiplex PCR technique (for genes sea and seb) i.e. the Real-Time PCR technique for genes sec, sed and see. In all 26 strains of coagulase-positive staphylococci (originating from cheeses produced from raw or cooked milk, which were enterotoxin producers) sea was present, and in 24 strains in addition to sea gene, seb was detected. None of the isolates possessed genes for the synthesis of enterotoxin C (SEC), D (SED) and E (SEE). Out of 26 tested cheese samples positive for enterotoxigenic coagulase-positive staphylococci, enterotoxin was detected in 2 (7.69%) samples of sweet-coagulating cheese, in which the number of enterotoxigenic coagulase-positive staphylococci exceeded 5 log CFU g-1. In sweet-coagulating cheeses in which the number of coagulase-positive staphylococci exceeds 5 log CFU g-1 and the pH value was higher than 5.0, enterotoxins may be present in amounts sufficient to cause intoxication.
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22
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Nunes Silva B, Cadavez V, Teixeira JA, Gonzales-Barron U. Effects of Essential Oils on Escherichia coli Inactivation in Cheese as Described by Meta-Regression Modelling. Foods 2020; 9:foods9060716. [PMID: 32498276 PMCID: PMC7353537 DOI: 10.3390/foods9060716] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 05/24/2020] [Accepted: 05/27/2020] [Indexed: 12/22/2022] Open
Abstract
The growing intention to replace chemical food preservatives with plant-based antimicrobials that pose lower risks to human health has produced numerous studies describing the bactericidal properties of biopreservatives such as essential oils (EOs) in a variety of products, including cheese. This study aimed to perform a meta-analysis of literature data that could summarize the inactivation of Escherichia coli in cheese achieved by added EOs; and compare its inhibitory effectiveness by application method, antimicrobial concentration, and specific antimicrobials. After a systematic review, 362 observations on log reduction data and study characteristics were extracted from 16 studies. The meta-regression model suggested that pathogenic E. coli is more resistant to EO action than the non-pathogenic type (p < 0.0001), although in both cases the higher the EO dose, the greater the mean log reduction achieved (p < 0.0001). It also showed that, among the factual application methods, EOs' incorporation in films render a steadier inactivation (p < 0.0001) than when directly applied to milk or smeared on cheese surface. Lemon balm, sage, shallot, and anise EOs showed the best inhibitory outcomes against the pathogen. The model also revealed the inadequacy of inoculating antimicrobials in cheese purposely grated for performing challenge studies, as this non-realistic application overestimates (p < 0.0001) the inhibitory effects of EOs.
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Affiliation(s)
- Beatriz Nunes Silva
- Centro de Investigação de Montanha (CIMO), Instituto Politécnico de Bragança, Campus de Santa Apolónia, 5300-253 Bragança, Portugal; (B.N.S.); (V.C.)
- CEB – Centre of Biological Engineering, University of Minho, Campus Gualtar, 4710–057 Braga, Portugal;
| | - Vasco Cadavez
- Centro de Investigação de Montanha (CIMO), Instituto Politécnico de Bragança, Campus de Santa Apolónia, 5300-253 Bragança, Portugal; (B.N.S.); (V.C.)
| | - José António Teixeira
- CEB – Centre of Biological Engineering, University of Minho, Campus Gualtar, 4710–057 Braga, Portugal;
| | - Ursula Gonzales-Barron
- Centro de Investigação de Montanha (CIMO), Instituto Politécnico de Bragança, Campus de Santa Apolónia, 5300-253 Bragança, Portugal; (B.N.S.); (V.C.)
- Correspondence: ; Tel.: +35-12-7330-3325
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23
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Use of indicator bacteria for monitoring sanitary quality of raw milk cheeses – A literature review. Food Microbiol 2020; 85:103283. [DOI: 10.1016/j.fm.2019.103283] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 06/06/2019] [Accepted: 07/30/2019] [Indexed: 11/17/2022]
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24
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Costanzo N, Ceniti C, Santoro A, Clausi MT, Casalinuovo F. Foodborne Pathogen Assessment in Raw Milk Cheeses. INTERNATIONAL JOURNAL OF FOOD SCIENCE 2020; 2020:3616713. [PMID: 32064273 PMCID: PMC6996669 DOI: 10.1155/2020/3616713] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 12/11/2019] [Indexed: 12/12/2022]
Abstract
General hygienic parameters and selected foodborne pathogens in raw milk cheeses at the retail level were evaluated. A total of 245 raw milk cheese samples were analysed for total bacterial count, Enterobacteriaceae, E. coli, Salmonella spp., Listeria monocytogenes, coagulase-positive Staphylococci, and staphylococcal enterotoxin. Results showed only 3 samples that were not compliant with European rules on staphylococcal enterotoxin, but coagulase-positive Staphylococci were evidenced in all samples tested. Salmonella spp. and Listeria monocytogenes were never detected whereas E. coli was evidenced in 20 samples. Results suggest a need for improvement of good manufacturing practice and milking operation.
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Affiliation(s)
- Nicola Costanzo
- Department of Health Sciences, University “Magna Græcia” of Catanzaro, Campus Universitario “S. Venuta”, Viale “S. Venuta”, I-88100 Catanzaro, Italy
| | - Carlotta Ceniti
- Department of Health Sciences, University “Magna Græcia” of Catanzaro, Campus Universitario “S. Venuta”, Viale “S. Venuta”, I-88100 Catanzaro, Italy
| | - Adriano Santoro
- Department of Veterinary Medicine and Animal Production, University “Federico II” of Naples, Via Delpino 1, 80100 Napoli, Italy
| | - Maria Teresa Clausi
- Istituto Zooprofilattico Sperimentale del Mezzogiorno, Viale Crotone, Catanzaro 88100, Italy
| | - Francesco Casalinuovo
- Istituto Zooprofilattico Sperimentale del Mezzogiorno, Viale Crotone, Catanzaro 88100, Italy
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25
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Extracellular Membrane Vesicles from Lactobacilli Dampen IFN-γ Responses in a Monocyte-Dependent Manner. Sci Rep 2019; 9:17109. [PMID: 31745234 PMCID: PMC6864076 DOI: 10.1038/s41598-019-53576-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 11/01/2019] [Indexed: 12/01/2022] Open
Abstract
Secreted factors derived from Lactobacillus are able to dampen pro-inflammatory cytokine responses. Still, the nature of these components and the underlying mechanisms remain elusive. Here, we aimed to identify the components and the mechanism involved in the Lactobacillus-mediated modulation of immune cell activation. PBMC were stimulated in the presence of the cell free supernatants (CFS) of cultured Lactobacillus rhamnosus GG and Lactobacillus reuteri DSM 17938, followed by evaluation of cytokine responses. We show that lactobacilli-CFS effectively dampen induced IFN-γ and IL-17A responses from T- and NK cells in a monocyte dependent manner by a soluble factor. A proteomic array analysis highlighted Lactobacillus-induced IL-1 receptor antagonist (ra) as a potential candidate responsible for the IFN-γ dampening activity. Indeed, addition of recombinant IL-1ra to stimulated PBMC resulted in reduced IFN-γ production. Further characterization of the lactobacilli-CFS revealed the presence of extracellular membrane vesicles with a similar immune regulatory activity to that observed with the lactobacilli-CFS. In conclusion, we have shown that lactobacilli produce extracellular MVs, which are able to dampen pro-inflammatory cytokine responses in a monocyte-dependent manner.
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26
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Keklik NM, Elik A, Salgin U, Demirci A, Koçer G. Inactivation of Staphylococcus aureus and Escherichia coli O157:H7 on fresh kashar cheese with pulsed ultraviolet light. FOOD SCI TECHNOL INT 2019; 25:680-691. [PMID: 31272222 DOI: 10.1177/1082013219860925] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Pulsed ultraviolet light is a potential postprocessing decontamination method which is able to reduce pathogens on solid food surfaces. Cheese surfaces may become easily contaminated with pathogens due to improper handling or contact with unhygienic surfaces during or after processing. In this study, the effects of pulsed ultraviolet light on Staphylococcus aureus and Escherichia coli O157:H7 on fresh kashar cheese were investigated. Pulsed ultraviolet light was applied to kashar cheese for different times (5, 15, 30, 45, 60 s) at 5, 8, and 13 cm from the quartz window in a pulsed ultraviolet light system. Based on the inactivation level, time, and visual evaluation, the most favorable treatment was determined as the 45 s-13 cm treatment (∼44 J/cm2). This treatment yielded about 1.62 and 3.02 log10 reductions (cfu/cm2) for S. aureus and E. coli O157:H7, respectively, while did not alter (p>0.05) the pH, lipid oxidation, and moisture content of kashar cheese, except the color parameters. When 0.5 cm thick kashar cheese was treated with pulsed ultraviolet light at a distance of 5 cm from the quartz window, the highest energy transmittance was found to be about 9.16%. These findings demonstrate that pulsed ultraviolet light has the potential for postprocessing decontamination of semi-hard cheese surfaces.
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Affiliation(s)
- Nene M Keklik
- 1 Department of Food Engineering, Faculty of Engineering, Sivas Cumhuriyet University, Sivas, Turkey
| | - Adil Elik
- 2 Department of Chemistry, Faculty of Science, Sivas Cumhuriyet University, Sivas, Turkey
| | - Uğur Salgin
- 3 Department of Chemical Engineering, Faculty of Engineering, Sivas Cumhuriyet University, Sivas, Turkey
| | - Ali Demirci
- 4 Agricultural and Biological Engineering, The Pennsylvania State University, University Park, USA
| | - Gamze Koçer
- 1 Department of Food Engineering, Faculty of Engineering, Sivas Cumhuriyet University, Sivas, Turkey
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27
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Zeaki N, Johler S, Skandamis PN, Schelin J. The Role of Regulatory Mechanisms and Environmental Parameters in Staphylococcal Food Poisoning and Resulting Challenges to Risk Assessment. Front Microbiol 2019; 10:1307. [PMID: 31244814 PMCID: PMC6581702 DOI: 10.3389/fmicb.2019.01307] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 05/27/2019] [Indexed: 11/29/2022] Open
Abstract
Prevention, prediction, control, and handling of bacterial foodborne diseases - an ongoing, serious, and costly concern worldwide - are continually facing a wide array of difficulties. Not the least due to that food matrices, highly variable and complex, can impact virulence expression in diverse and unpredictable ways. This review aims to present a comprehensive overview of challenges related to the presence of enterotoxigenic Staphylococcus aureus in the food production chain. It focuses on characteristics, expression, and regulation of the highly stable staphylococcal enterotoxins and in particular staphylococcal enterotoxin A (SEA). Together with the robustness of the pathogen under diverse environmental conditions and the range of possible entry routes into the food chain, this poses some of the biggest challenges in the control of SFP. Furthermore, the emergence of new enterotoxins, found to be connected with SFP, brings new questions around their regulatory mechanisms and expression in different food environments. The appearance of increasing amounts of antibiotic resistant strains found in food is also highlighted. Finally, potentials and limitations of implementing existing risk assessment models are discussed. Various quantitative microbial risk assessment approaches have attempted to quantify the growth of the bacterium and production of disease causing levels of toxin under various food chain and domestic food handling scenarios. This requires employment of predictive modeling tools, quantifying the spatiotemporal population dynamics of S. aureus in response to intrinsic and extrinsic food properties. In this context, the armory of predictive modeling employs both kinetic and probabilistic models to estimate the levels that potentiate toxin production, the time needed to reach that levels, and overall, the likelihood of toxin production. Following risk assessment, the main challenge to mitigate the risk of S. aureus intoxication is first to prevent growth of the organism and then to hamper the production of enterotoxins, or at least prevent the accumulation of high levels (e.g., >10-20 ng) in food. The necessity for continued studies indeed becomes apparent based on the challenges to understand, control, and predict enterotoxin production in relation to the food environment. Different types of food, preservatives, processing, and packaging conditions; regulatory networks; and different staphylococcal enterotoxin-producing S. aureus strains need to be further explored to obtain more complete knowledge about the virulence of this intriguing pathogen.
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Affiliation(s)
- Nikoleta Zeaki
- Division of Applied Microbiology, Department of Chemistry, Lund University, Lund, Sweden
| | - Sophia Johler
- Institute for Food Safety and Hygiene, University of Zurich, Zurich, Switzerland
| | - Panagiotis N. Skandamis
- Laboratory of Food Quality Control and Hygiene, Department of Food Science and Human Nutrition, Agricultural University of Athens, Athens, Greece
| | - Jenny Schelin
- Division of Applied Microbiology, Department of Chemistry, Lund University, Lund, Sweden
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28
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Dai J, Wu S, Huang J, Wu Q, Zhang F, Zhang J, Wang J, Ding Y, Zhang S, Yang X, Lei T, Xue L, Wu H. Prevalence and Characterization of Staphylococcus aureus Isolated From Pasteurized Milk in China. Front Microbiol 2019; 10:641. [PMID: 31001225 PMCID: PMC6454862 DOI: 10.3389/fmicb.2019.00641] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 03/13/2019] [Indexed: 11/13/2022] Open
Abstract
Staphylococcus aureus is one of the most important food-borne pathogens globally. It produces various toxins and invasive enzymes and can be found in numerous food products. Milk is an important source of staphylococcal food poisoning. After pasteurization, this microorganism or its enterotoxins might still remain in pasteurized milk. Therefore, this study was to investigate the contamination of S. aureus in 258 pasteurized milk from 39 cities of China. The prevalence and levels of S. aureus in these samples as well as antibiotic susceptibility profiles, virulence genes, biofilm formation, and biofilm related genes, spa typing and MLST were used to determine the characterization among the isolates. It was found 3.9% of samples were detected S. aureus in 8 of 39 cities in China. The contaminated level were not very excessive which showed the MPN values of the most positive samples (9/10) were less than 1 MPN/g. All pasteurized milk-related S. aureus isolates have ability to produce biofilm and harbored icaA, icaD, eno, clfA, clfB, fnbA, fnbB, fib genes, other biofilm related genes icaC were showed in 91.7% of isolates and cna gene were showed in 50%, except bap gene which were free in all isolates. The antibiotic susceptibility test showed that all isolates were resistant or intermediate-resistant to different concentrations of the antibiotics. Furthermore, 75.0% of the isolates were resistant to three or more antibiotic classes, which indicated multidrug resistance. The isolates had virulence potential, which showed 66.7% (8/12) of the isolates carried one or more virulence-associated genes. Molecular typing by MLST and spa typing enabled classification of these isolates into a total of 11 sequence types (STs) and spa types, which indicated high genetic diversity. Most of these types were related to various clinical S. aureus infections. Thus, the findings of this study reflect the potential risk of S. aureus infection in China. Our study also provides comprehensive analysis of the prevalence of S. aureus in pasteurized milk and helps ensure more accurate treatment of human infection with effective antibiotics.
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Affiliation(s)
- Jingsha Dai
- Guangdong Institute of Microbiology, State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangzhou, China
| | - Shi Wu
- Guangdong Institute of Microbiology, State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangzhou, China
| | - Jiahui Huang
- Guangdong Institute of Microbiology, State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangzhou, China
| | - Qingping Wu
- Guangdong Institute of Microbiology, State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangzhou, China
| | - Feng Zhang
- Guangdong Institute of Microbiology, State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangzhou, China.,School of Bioscience and Bioengineering, South China University of Technology, Guangzhou, China
| | - Jumei Zhang
- Guangdong Institute of Microbiology, State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangzhou, China
| | - Juan Wang
- College of Food Science, South China Agricultural University, Guangzhou, China
| | - Yu Ding
- Department of Food Science and Technology, Jinan University, Guangzhou, China
| | - Shuhong Zhang
- Guangdong Institute of Microbiology, State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangzhou, China
| | - Xiaojuan Yang
- Guangdong Institute of Microbiology, State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangzhou, China
| | - Tao Lei
- Guangdong Institute of Microbiology, State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangzhou, China
| | - Liang Xue
- Guangdong Institute of Microbiology, State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangzhou, China
| | - Haoming Wu
- Guangdong Institute of Microbiology, State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangzhou, China
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29
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Korpysa-Dzirba W, Osek J. Molecular Characterization of EnterotoxigenicStaphylococcus aureusIsolated from Raw Cow Milk in Poland. Foodborne Pathog Dis 2019; 16:114-118. [DOI: 10.1089/fpd.2018.2482] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Weronika Korpysa-Dzirba
- Department of Hygiene of Food of Animal Origin, National Veterinary Research Institute, Pulawy, Poland
| | - Jacek Osek
- Department of Hygiene of Food of Animal Origin, National Veterinary Research Institute, Pulawy, Poland
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30
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Chatterjee A, Modarai M, Naylor NR, Boyd SE, Atun R, Barlow J, Holmes AH, Johnson A, Robotham JV. Quantifying drivers of antibiotic resistance in humans: a systematic review. THE LANCET. INFECTIOUS DISEASES 2018; 18:e368-e378. [PMID: 30172580 DOI: 10.1016/s1473-3099(18)30296-2] [Citation(s) in RCA: 175] [Impact Index Per Article: 29.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Revised: 03/26/2018] [Accepted: 05/01/2018] [Indexed: 02/06/2023]
Abstract
Mitigating the risks of antibiotic resistance requires a horizon scan linking the quality with the quantity of data reported on drivers of antibiotic resistance in humans, arising from the human, animal, and environmental reservoirs. We did a systematic review using a One Health approach to survey the key drivers of antibiotic resistance in humans. Two sets of reviewers selected 565 studies from a total of 2819 titles and abstracts identified in Embase, MEDLINE, and Scopus (2005-18), and the European Centre for Disease Prevention and Control, the US Centers for Disease Control and Prevention, and WHO (One Health data). Study quality was assessed in accordance with Cochrane recommendations. Previous antibiotic exposure, underlying disease, and invasive procedures were the risk factors with most supporting evidence identified from the 88 risk factors retrieved. The odds ratios of antibiotic resistance were primarily reported to be between 2 and 4 for these risk factors when compared with their respective controls or baseline risk groups. Food-related transmission from the animal reservoir and water-related transmission from the environmental reservoir were frequently quantified. Uniformly quantifying relationships between risk factors will help researchers to better understand the process by which antibiotic resistance arises in human infections.
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Affiliation(s)
- Anuja Chatterjee
- National Institute for Health Research, Health Protection Research Unit in Healthcare Associated Infection and Antimicrobial Resistance, Imperial College London, London, UK.
| | - Maryam Modarai
- National Institute for Health Research, Health Protection Research Unit in Healthcare Associated Infection and Antimicrobial Resistance, Imperial College London, London, UK
| | - Nichola R Naylor
- National Institute for Health Research, Health Protection Research Unit in Healthcare Associated Infection and Antimicrobial Resistance, Imperial College London, London, UK
| | - Sara E Boyd
- National Institute for Health Research, Health Protection Research Unit in Healthcare Associated Infection and Antimicrobial Resistance, Imperial College London, London, UK; Imperial College London Healthcare NHS Trust, London, UK; Antimicrobial Pharmacodynamics and Therapeutics, Department of Molecular and Clinical Pharmacology, University of Liverpool, Liverpool, UK
| | - Rifat Atun
- National Institute for Health Research, Health Protection Research Unit in Healthcare Associated Infection and Antimicrobial Resistance, Imperial College London, London, UK; Department of Global Health and Population, and Department of Health Policy and Management, Harvard University, Boston, MA, USA
| | - James Barlow
- Centre for Health Economics & Policy Innovation, Imperial College Business School, London, UK
| | - Alison H Holmes
- National Institute for Health Research, Health Protection Research Unit in Healthcare Associated Infection and Antimicrobial Resistance, Imperial College London, London, UK; Imperial College London Healthcare NHS Trust, London, UK
| | - Alan Johnson
- National Institute for Health Research, Health Protection Research Unit in Healthcare Associated Infection and Antimicrobial Resistance, Imperial College London, London, UK; Department of Healthcare-Associated Infections and Antimicrobial Resistance, National Infection Service, Public Health England, London, UK
| | - Julie V Robotham
- National Institute for Health Research, Health Protection Research Unit in Healthcare Associated Infection and Antimicrobial Resistance, Imperial College London, London, UK; Modelling and Economics Unit, National Infection Service, Public Health England, London, UK
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31
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Dambrosio A, Ioanna F, Storelli MM, Castiglia D, Giannico F, Colonna MA, De Rosa M, Quaglia NC. Microbiological quality and safety of cheeses belonging to “Traditional Agri‐Food Products” (T.A.P.) produced in Southern Italy. J Food Saf 2018. [DOI: 10.1111/jfs.12539] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Angela Dambrosio
- Department of Emergency and Organ Transplantation, Section of Veterinary Clinic and Animal ProductionUniversity of Bari Aldo Moro Bari Italy
| | | | - Maria M. Storelli
- Department of Biosciences, Biotechnologies and BiopharmaceuticalUniversity of Bari Aldo Moro Bari Italy
| | | | - Francesco Giannico
- Department of Agricultural and Environmental ScienceUniversity of Bari Aldo Moro, University campus "Ernesto Quagliariello" Bari Italy
| | - Maria A. Colonna
- Department of Agricultural and Environmental ScienceUniversity of Bari Aldo Moro, University campus "Ernesto Quagliariello" Bari Italy
| | | | - Nicoletta C. Quaglia
- Department of Emergency and Organ Transplantation, Section of Veterinary Clinic and Animal ProductionUniversity of Bari Aldo Moro Bari Italy
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32
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Gérard A, El-Hajjaji S, Niyonzima E, Daube G, Sindic M. Prevalence and survival of Listeria monocytogenes
in various types of cheese-A review. INT J DAIRY TECHNOL 2018. [DOI: 10.1111/1471-0307.12552] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Amaury Gérard
- Laboratory of Quality and Safety of Agro-Food Products; Gembloux Agro-Bio Tech; University of Liège; Passage des Déportés, 2 5030 Gembloux Belgium
| | - Soundous El-Hajjaji
- Laboratory of Quality and Safety of Agro-Food Products; Gembloux Agro-Bio Tech; University of Liège; Passage des Déportés, 2 5030 Gembloux Belgium
| | - Eugène Niyonzima
- Food Safety and Quality Management Department; School of Food Science and Technology; University of Rwanda; Avenue de l'armée, P.O. Box 3900 Kigali Rwanda
| | - Georges Daube
- Food Science Department; Faculty of Veterinary Medicine; FARAH, University of Liège; Sart-Tilman B43b 4000 Liège Belgium
| | - Marianne Sindic
- Laboratory of Quality and Safety of Agro-Food Products; Gembloux Agro-Bio Tech; University of Liège; Passage des Déportés, 2 5030 Gembloux Belgium
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33
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Antibiotic-resistance, enterotoxin gene profiles and farm-level prevalence of Staphylococcus aureus in cow, sheep and goat bulk tank milk in Jordan. Int Dairy J 2018. [DOI: 10.1016/j.idairyj.2018.02.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Artursson K, Schelin J, Thisted Lambertz S, Hansson I, Olsson Engvall E. Foodborne pathogens in unpasteurized milk in Sweden. Int J Food Microbiol 2018; 284:120-127. [PMID: 29887505 DOI: 10.1016/j.ijfoodmicro.2018.05.015] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 05/11/2018] [Accepted: 05/17/2018] [Indexed: 11/15/2022]
Abstract
Raw milk may be a risk for public health if it is contaminated with zoonotic pathogens. To study the prevalence in unpasteurized milk from Swedish farms, bovine and small ruminant dairy farms were sampled. Since the sampling method and transport conditions may influence the outcome of analyses, efforts were made to optimize the methodology. Culturing of bacteria was done from in-line milk filters collected from the milk pipe at the point where it enters the milk bulk tank at the farms and this way of sampling was compared to sampling bulk tank milk (BTM) directly. Analysing milk filters were found to be superior to analysing BTM directly. Conditions for transport of milk filter samples were further improved by the addition of Cary Blair transport medium, which significantly increased the number of positive samples for pathogenic bacteria. The isolation of several foodborne pathogens from milk filters was demonstrated. The prevalence of samples with Staphylococcus aureus was 71% and 64%, and Listeria spp. 21% and 29% from dairy cow and goat/sheep farms, respectively. Campylobacter jejuni, Yersinia enterocolitica and verotoxigenic Escherichia coli (VTEC) O157 were detected in 9%, 2% and 2% of samples from bovine milk, respectively. We conclude that the choice of sampling method and sample handling influence the results of bacterial culturing. From the results of this study, we strongly recommend to sample in-line milk filters instead of BTM directly and to use Cary Blair medium during transport, especially if the samples are to be analysed for Campylobacter spp. and/or Listeria spp. The findings also show that unpasteurized milk from Swedish farms occasionally contain bacteria with zoonotic potential.
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Affiliation(s)
- Karin Artursson
- National Veterinary Institute, Uppsala, Sweden; Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, Sweden.
| | - Jenny Schelin
- Applied Microbiology, Faculty of Engineering, Lund University, Lund, Sweden
| | - Susanne Thisted Lambertz
- Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, Sweden; National Food Agency, Uppsala, Sweden
| | - Ingrid Hansson
- National Veterinary Institute, Uppsala, Sweden; Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, Sweden
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Lucchini R, Cardazzo B, Carraro L, Negrinotti M, Balzan S, Novelli E, Fasolato L, Fasoli F, Farina G. Contribution of natural milk culture to microbiota, safety and hygiene of raw milk cheese produced in alpine malga. Ital J Food Saf 2018; 7:6967. [PMID: 29732331 PMCID: PMC5913705 DOI: 10.4081/ijfs.2018.6967] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 11/10/2017] [Accepted: 11/11/2017] [Indexed: 01/23/2023] Open
Abstract
Processing of alpine milk in malga farms is carried out under conditions that can favor contamination by coliforms, coagulase-positive staphylococci, or pathogens such as Listeria monocytogenes. With the aim to improve the hygienic characteristics and safety of cheese produced in four malga farms the use of lyophilized Natural Milk Culture prepared with selected strains was tested.. Two cheesemaking tests were carried out in the same day always starting from the same milk: in the first case following the malga recipe that uses either Natural Whey Culture or without the addition of a starter, in the second one using a Natural Milk Culture. Cheesemaking were carried out in four malga farms located in the west area of Trentino region within the same week. For hygienic and safety evaluation, aerobic colony count, coagulase-positive staphylococci, Escherichia coli, staphylococcal toxins, Listeria monocytogenes, and Salmonella spp, pH and aw were determined in raw milk from evening and morning milking, curd in vat, curd after extraction and two months-ripened cheese. Pathogens or toxins, high values of coagulase- positive staphylococci and E. coli were not found in cheese samples. However, in the curd coagulase-positive staphylococci reached values almost of 5 Log CFU/g in the two malga without starter cultures. The use of Natural Milk Culture reduced E. coli counts. In addition, DNA was extracted from cheese samples and from Natural Milk Culture and the composition of the microbial community determined by Next Generation Sequencing method. The determination of cheese microbial communities demonstrated that the use of Natural Milk Culture exerted different effects in the different malga, in any case preserving bacterial biodiversity.
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Affiliation(s)
- Rosaria Lucchini
- Institute for Experimental Veterinary Medicine of Venezia, Section of Trento
| | - Barbara Cardazzo
- Department of Comparative Biomedicine and Food Science, University of Padua
| | - Lisa Carraro
- Department of Comparative Biomedicine and Food Science, University of Padua
| | - Michele Negrinotti
- Operative Unit of Hygiene and Veterinary Public Health, Agency for Healthcare Services of Autonomous Province of Trento, Italy
| | - Stefania Balzan
- Department of Comparative Biomedicine and Food Science, University of Padua
| | - Enrico Novelli
- Department of Comparative Biomedicine and Food Science, University of Padua
| | - Luca Fasolato
- Department of Comparative Biomedicine and Food Science, University of Padua
| | - Franco Fasoli
- Operative Unit of Hygiene and Veterinary Public Health, Agency for Healthcare Services of Autonomous Province of Trento, Italy
| | - Giovanni Farina
- Institute for Experimental Veterinary Medicine of Venezia, Section of Trento
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Gonzalez AGM, Marques LMP, Gomes MDSA, Beltrão JCDC, Pinheiro MG, Esper LMR, Paula GRD, Teixeira LA, Aguiar-Alves F. Methicillin-resistant Staphylococcus aureus in minas frescal cheese: evaluation of classic enterotoxin genes, antimicrobial resistance and clonal diversity. FEMS Microbiol Lett 2018; 364:4584464. [PMID: 29099921 DOI: 10.1093/femsle/fnx232] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 10/31/2017] [Indexed: 01/24/2023] Open
Abstract
This study aimed to investigate classical enterotoxin (sea to see) and mecA genes, by polymerase chain reaction and anitimicrobial susceptibility, by disk diffusion test of Staphylococcus aureus isolated from minas frescal cheese (MFC). All methicillin-resistant S. aureus (MRSA) isolates were investigated for the presence of Panton-Valentine leukocidin (PVL) genes and clonal diversity. Thirty-one S. aureus were isolated from four MFC samples. Seven (22.6%) S. aureus carried mecA gene and two of them carried enterotoxin genes seb/sec and sea/seb. Five (16.1%) S. aureus isolates showed induced resistance to clindamycin and nine (29%) were resistant to multiple -antibiotics (MDR), among these, six were MRSA. No MRSA isolates presented the PVL genes. Four MRSA were grouped into three clones and three isolates were not typable by pulsed field gel electrophoresis. MRSA isolates showed, by multilocus sequence typing, sequence types ST1, ST5, ST72 and ST4304 (new ST) and S. aureus protein A (spa type) t127, t568 and t2703. These data suggest that MFC may constitute a risk to the consumer because of its potential for staphylococcal food poisoning; however it might, also, become one of MRSA and MDR strains disseminator, including clones usually found in the hospital environment.
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Affiliation(s)
| | - Leila Márcia Peres Marques
- Departamento de Bromatologia, Faculdade de Farmácia, Universidade Federal Fluminense, Niterói, RJ 24241-000, Brasil
| | - Marcel da Silva Amorim Gomes
- Departamento de Bromatologia, Faculdade de Farmácia, Universidade Federal Fluminense, Niterói, RJ 24241-000, Brasil
| | | | - Marcos Gabriel Pinheiro
- Programa de Pós Graduacao em Patologia, Faculdade de Medicina, Universidade Federal Fluminense, Niterói, RJ 24033-900, Brasil
| | - Luciana Maria Ramires Esper
- Departamento de Bromatologia, Faculdade de Farmácia, Universidade Federal Fluminense, Niterói, RJ 24241-000, Brasil
| | - Geraldo Renato de Paula
- Departamento de Tecnologia de Medicamentos e Cosméticos, Faculdade de Farmácia, Universidade Federal Fluminense, Niterói, RJ 24241-000, Brasil
| | - Lenise Arneiro Teixeira
- Departamento de Tecnologia de Medicamentos e Cosméticos, Faculdade de Farmácia, Universidade Federal Fluminense, Niterói, RJ 24241-000, Brasil
| | - Fábio Aguiar-Alves
- Programa de Pós Graduacao em Patologia, Faculdade de Medicina, Universidade Federal Fluminense, Niterói, RJ 24033-900, Brasil
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38
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Kim NH, Lee NY, Kim MG, Kim HW, Cho TJ, Joo IS, Heo EJ, Rhee MS. Microbiological criteria and ecology of commercially available processed cheeses according to the product specification and physicochemical characteristics. Food Res Int 2018; 106:468-474. [PMID: 29579949 DOI: 10.1016/j.foodres.2018.01.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2017] [Revised: 01/06/2018] [Accepted: 01/09/2018] [Indexed: 11/25/2022]
Abstract
Although global cheese manufacturers release a variety of products onto the market, research on the microbiological quality and safety of cheese has focused mainly on conventional cheeses made from milk. Here, this study aimed to investigate commercially processed cheese products produced by mixing conventional cheeses after melting. Two approaches were used: a summary and comparison of legal definitions and standards/regulations regarding the microbiological criteria used by major cheese traders in the global market (Australia/New Zealand, China, European Union, Japan, Mexico, Republic of Korea, and the United States) and a comprehensive microbiological analysis of commercial products (n = 800), along with an assessment of salinity, pH, water activity, and heating conditions. The results of the literature search showed that major importing countries (China, Japan, Mexico, and the Republic of Korea) have stricter microbiological criteria for commercially available cheese products than major exporters (Australia/New Zealand, EU, and the USA). The former set limits with respect to the number of total coliforms in the product. Microbiological analyses were designed according to global standards and recommendations. No test sample contained detectable levels of Clostridium perfringens, enterohemorrhagic Escherichia coli, Listeria monocytogenes, Salmonella, or Staphylococcus aureus. In addition, no coliform bacteria (including E. coli) were detected. Overall, 79.9% of the samples contained detectable aerobic plate counts (1.0-7.8 log CFU/g); these levels varied significantly according to product type (grated cheese > chunks; cream cheese > portions or sliced) (p < .05). There was no significant association between microbe levels and salinity, water activity, pH, and heating conditions. The results can be used to develop a comprehensive database about commercially processed cheese products available in the global market and, as such, may be helpful for both national authorities and cheese manufacturers when considering novel strategic management plans for microbiological quality and safety.
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Affiliation(s)
- Nam Hee Kim
- Department of Biotechnology, College of Life Science and Biotechnology, Korea University, Seoul 02841, Republic of Korea
| | - Na Young Lee
- Department of Biotechnology, College of Life Science and Biotechnology, Korea University, Seoul 02841, Republic of Korea
| | - Min Gyu Kim
- Department of Biotechnology, College of Life Science and Biotechnology, Korea University, Seoul 02841, Republic of Korea
| | - Hye Won Kim
- Department of Biotechnology, College of Life Science and Biotechnology, Korea University, Seoul 02841, Republic of Korea
| | - Tae Jin Cho
- Department of Biotechnology, College of Life Science and Biotechnology, Korea University, Seoul 02841, Republic of Korea
| | - In Sun Joo
- Food Microbiology Division, National Institute of Food and Drug Safety Evaluation, Chungcheongbuk-do 28159, Republic of Korea
| | - Eun Jung Heo
- Food Microbiology Division, National Institute of Food and Drug Safety Evaluation, Chungcheongbuk-do 28159, Republic of Korea
| | - Min Suk Rhee
- Department of Biotechnology, College of Life Science and Biotechnology, Korea University, Seoul 02841, Republic of Korea.
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39
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Brown SRB, Millán-Borrero NC, Carbonella JC, Micheletti AJP, D'Amico DJ. Acidification of Model Cheese Brines To Control Listeria monocytogenes. J Food Prot 2018; 81:79-83. [PMID: 29271687 DOI: 10.4315/0362-028x.jfp-17-325] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Cheese brines are often used for prolonged periods, with adjustments made only to pH and salt content. Pathogens, including Salmonella enterica Typhimurium, Escherichia coli O157:H7, and Listeria monocytogenes, have been shown to survive long periods in model and commercial brines under common brining conditions. The objective of this study was to determine the survival of L. monocytogenes in model cheese brines, with and without whey added at 2%, when acidified to a pH of 2 using food-grade acids. Survival in untreated brines over a 6-month period was also assessed. Cultures of L. monocytogenes were propagated to induce salt and acid tolerance prior to inoculation at ∼6 log CFU/mL into model brines (pH 5.2, 20% NaCl). Following a week-long adaption period at 12°C, inoculated brines were acidified to pH 2.0 within 15 min using either hydrochloric, acetic, citric, or lactic acid, held at that pH for up to 24 h, and neutralized prior to enumeration and enrichment. Overall, each acid treatment was capable of achieving ≥5-log reductions in L. monocytogenes counts within 135 min at pH 2. Hydrochloric acid required the lowest volume to achieve treatment pH and was the most effective treatment in the absence of whey. However, it was the least effective in the presence of whey. Acetic acid produced rapid inactivation in both brines but required impractical volumes of acid to reach the treatment pH. Citric acid was similarly effective in both brines but was the second least effective in terms of time to achieve a ≥5-log reduction. Although only slight and insignificant differences were observed, lactic acid appears to be the more practical and promising approach for the inactivation of L. monocytogenes in cheese brines by producing the most rapid inactivation in the presence and absence of whey. Acidification as a preventive control for L. monocytogenes could increase adoption of brine treatments by small-scale cheese producers, thereby reducing food safety risks.
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Affiliation(s)
- Stephanie R B Brown
- 1 Department of Animal Science, 302B Agricultural Biotechnology Laboratory, 1390 Storrs Road, U-4163
| | - Nathalia C Millán-Borrero
- 2 Department of Molecular and Cell Biology, 91 North Eagleville Road, U-3125, University of Connecticut, Storrs, Connecticut 06269, USA
| | - Jeffrey C Carbonella
- 2 Department of Molecular and Cell Biology, 91 North Eagleville Road, U-3125, University of Connecticut, Storrs, Connecticut 06269, USA
| | - Anthony J P Micheletti
- 2 Department of Molecular and Cell Biology, 91 North Eagleville Road, U-3125, University of Connecticut, Storrs, Connecticut 06269, USA
| | - Dennis J D'Amico
- 1 Department of Animal Science, 302B Agricultural Biotechnology Laboratory, 1390 Storrs Road, U-4163
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40
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Bulajic S, Colovic S, Misic D, Djordjevic J, Savic-Radovanovic R, Asanin J, Ledina T. Enterotoxin production and antimicrobial susceptibility in Staphylococci isolated from traditional raw milk cheeses in Serbia. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART. B, PESTICIDES, FOOD CONTAMINANTS, AND AGRICULTURAL WASTES 2017; 52:864-870. [PMID: 28949803 DOI: 10.1080/03601234.2017.1361764] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
This study was undertaken to determine the prevalence of coagulase positive staphylococci (CPS) by examining a total of 71 raw milk cheeses. Additionally, enterotoxigenicity, antimicrobial susceptibility and the presence of mecA and mecC genes in the staphylococcal isolates were investigated. The isolation and enumeration procedure of CPS followed the International Organization for Standardization (ISO) standard. The presumptive staphylococci were identified by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) using the VITEK MS system. VIDAS® Staph enterotoxin II assay was used for the detection of classical enterotoxins. Antimicrobial susceptibility testing (AST) was accomplished performing the disk diffusion method. All suspected methicillin resistant staphylococci were investigated for the presence of mecA and mecC genes by PCR assay. A high prevalence (87.32%) of CPS was detected in the cheeses at contamination levels up to 5.58 log CFU g-1. Among 47 staphylococcal isolates screened for enterotoxin production, only one isolate, identified as S. hyicus, was confirmed as being enterotoxigenic. Resistance to penicillin (63.70%) was the most common resistance among the tested Staphylococcus aureus isolates. The dominant phenotypic resistance patterns in coagulase negative staphylococci (CNS) were resistance to ofloxacin and fusidic acid. All CNS isolates were susceptible to the clinically important antibiotics clindamycin, chloramphenicol, gentamicin, linezolid, rifampicin and trimethoprim-sulfamethoxazole. The mecA and mecC genes were not detected. To the best of our knowledge, this is the first study concerning evaluation of the presence of methicillin resistant staphylococci (MRS) in dairy products in Serbia.
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Affiliation(s)
- Snezana Bulajic
- a Faculty of Veterinary Medicine, Department of Food Hygiene and Technology , University of Belgrade , Bulevar Oslobodjenja 18, Belgrade , Serbia
| | - Svetlana Colovic
- b Department of Sanitary Microbiology , Institute of Public Health of Belgrade , Bulevar Despota Stefana 54a, Belgrade , Serbia
| | - Dusan Misic
- c Faculty of Veterinary Medicine, Department of Microbiology and Immunology , University of Belgrade , Bulevar Oslobodjenja 18, Belgrade , Serbia
| | - Jasna Djordjevic
- a Faculty of Veterinary Medicine, Department of Food Hygiene and Technology , University of Belgrade , Bulevar Oslobodjenja 18, Belgrade , Serbia
| | - Radoslava Savic-Radovanovic
- a Faculty of Veterinary Medicine, Department of Food Hygiene and Technology , University of Belgrade , Bulevar Oslobodjenja 18, Belgrade , Serbia
| | - Jelena Asanin
- c Faculty of Veterinary Medicine, Department of Microbiology and Immunology , University of Belgrade , Bulevar Oslobodjenja 18, Belgrade , Serbia
| | - Tijana Ledina
- a Faculty of Veterinary Medicine, Department of Food Hygiene and Technology , University of Belgrade , Bulevar Oslobodjenja 18, Belgrade , Serbia
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41
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Gonzales-Barron U, Gonçalves-Tenório A, Rodrigues V, Cadavez V. Foodborne pathogens in raw milk and cheese of sheep and goat origin: a meta-analysis approach. Curr Opin Food Sci 2017. [DOI: 10.1016/j.cofs.2017.10.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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42
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Benkerroum N. Staphylococcal enterotoxins and enterotoxin-like toxins with special reference to dairy products: An overview. Crit Rev Food Sci Nutr 2017; 58:1943-1970. [DOI: 10.1080/10408398.2017.1289149] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Noreddine Benkerroum
- Department of Food Science and Agricultural Chemistry, Macdonald-Stewart Building, McGill University, Macdonald Campus, Sainte-Anne-de-Bellevue, Canada
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43
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Câmara SPA, Dapkevicius A, Rosa HJD, Silva CCG, Malcata FX, Enes Dapkevicius MLN. Physicochemical, biochemical, microbiological and safety aspects of Pico cheese: Assessment throughout maturation and on the final product. INT J DAIRY TECHNOL 2017. [DOI: 10.1111/1471-0307.12424] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Sandra P A Câmara
- IITAA-Institute of Agricultural and Environmental Research and Technology/Faculty of Agricultural and Environmental Sciences; University of the Azores; Rua Capitão João d'Ávila 9700-042 Angra do Heroísmo Portugal
| | - Airidas Dapkevicius
- IITAA-Institute of Agricultural and Environmental Research and Technology/Faculty of Agricultural and Environmental Sciences; University of the Azores; Rua Capitão João d'Ávila 9700-042 Angra do Heroísmo Portugal
| | - Henrique J D Rosa
- IITAA-Institute of Agricultural and Environmental Research and Technology/Faculty of Agricultural and Environmental Sciences; University of the Azores; Rua Capitão João d'Ávila 9700-042 Angra do Heroísmo Portugal
| | - Célia C G Silva
- IITAA-Institute of Agricultural and Environmental Research and Technology/Faculty of Agricultural and Environmental Sciences; University of the Azores; Rua Capitão João d'Ávila 9700-042 Angra do Heroísmo Portugal
| | - F Xavier Malcata
- Department of Chemical Engineering; University of Porto; Rua Dr. Roberto Frias 4200-465 Porto Portugal
| | - Maria L N Enes Dapkevicius
- IITAA-Institute of Agricultural and Environmental Research and Technology/Faculty of Agricultural and Environmental Sciences; University of the Azores; Rua Capitão João d'Ávila 9700-042 Angra do Heroísmo Portugal
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Zhang X, Jiang Y, Huang C, Shen J, Dong X, Chen G, Zhang W. Functionalized nanocomposites with the optimal graphene oxide/Au ratio for amplified immunoassay of E. coli to estimate quality deterioration in dairy product. Biosens Bioelectron 2017; 89:913-918. [DOI: 10.1016/j.bios.2016.09.098] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Revised: 09/26/2016] [Accepted: 09/27/2016] [Indexed: 12/26/2022]
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45
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Mehli L, Hoel S, Thomassen GMB, Jakobsen AN, Karlsen H. The prevalence, genetic diversity and antibiotic resistance of Staphylococcus aureus in milk, whey, and cheese from artisan farm dairies. Int Dairy J 2017. [DOI: 10.1016/j.idairyj.2016.10.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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46
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Chaves RD, Silva AR, Alvarenga VO, Pereira JL, Mousavi Khaneghah A. The modeling of time to enterotoxin detection ofStaphylococcus aureusin chicken meat. J Food Saf 2017. [DOI: 10.1111/jfs.12342] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Rafael D. Chaves
- Department of Food Science, Faculty of Food Engineering; University of Campinas (UNICAMP); Campinas São Paulo Brazil
| | | | - Verônica O. Alvarenga
- Department of Food Science, Faculty of Food Engineering; University of Campinas (UNICAMP); Campinas São Paulo Brazil
| | - José L. Pereira
- Department of Food Science, Faculty of Food Engineering; University of Campinas (UNICAMP); Campinas São Paulo Brazil
| | - Amin Mousavi Khaneghah
- Department of Food Science, Faculty of Food Engineering; University of Campinas (UNICAMP); Campinas São Paulo Brazil
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47
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Ferreira M, Bernardo L, Neves L, Campos M, Lamaro-Cardoso J, André M. Virulence profile and genetic variability of Staphylococcus aureus isolated from artisanal cheese. J Dairy Sci 2016; 99:8589-8597. [DOI: 10.3168/jds.2015-10732] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Accepted: 02/29/2016] [Indexed: 11/19/2022]
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48
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Tarekgne EK, Skjerdal T, Skeie S, Rudi K, Porcellato D, Félix B, Narvhus JA. Enterotoxin Gene Profile and Molecular Characterization of Staphylococcus aureus Isolates from Bovine Bulk Milk and Milk Products of Tigray Region, Northern Ethiopia. J Food Prot 2016; 79:1387-95. [PMID: 27497126 DOI: 10.4315/0362-028x.jfp-16-003] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Staphylococcal food poisoning (SFP) is an important foodborne disease worldwide, and milk and milk products are commonly associated with SFP outbreaks. The objectives of this study were to investigate the distribution of staphylococcal enterotoxin (se) genes in Staphylococcus aureus from raw cow's milk and milk products and to assess their genetic background with the spa typing method. Of the 549 samples (297 bulk milk and 162 milk product samples) collected from Tigray region, Northern Ethiopia, 160 (29.1%) were positive for S. aureus, of which 82 (51%) were found to harbor se genes by a modified multiplex PCR. Nine se genes were identified: sea (n = 12), seb (n = 3), sec (n = 3), sed(n = 4), seg (n = 49), seh (n = 2), sei (n = 40), sej (n = 1), and tsst-1 (n = 24). The classical type of genes accounted for 27%. Of the 82 enterotoxigenic isolates, 41.5 and 12.4% harbored two or more se genes, respectively. The highest gene association was observed between sei and seg, whereas sea and seb were always found together with the new types of se genes. Altogether, 18 genotypes of toxin genes were identified, and 33% of the samples contained > 5 log CFU ml(-1) S. aureus. spa typing identified 22 spa types and three novel spa sequences, which showed the high genetic diversity of the isolates. No apparent relationship was observed between spa type and se genes. Of the 25 spa types, 13 (52%) were from raw milk, 3 (12%) from milk products, and 9 (36%) from both types of sample. Types t314 (20.7%,n = 17), t458 (18.3%, n = 15), and t6218 (9.8%, n= 8) were the most common spa types identified and were widely distributed in three of the eight studied localities. This is the first study from the Tigray region to report the high distribution of enterotoxigenic S. aureus with a diversified genetic background from dairy food. The study may provide valuable data for microbial food safety risk assessment, molecular epidemiology, and phylogenetic studies of S. aureus in Ethiopia.
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Affiliation(s)
- Enquebaher K Tarekgne
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, N-1432 Ås, Norway; College of Veterinary Medicine, P.O. Box 1118, Mekelle University, Mekelle, Tigray, Ethiopia.
| | - Taran Skjerdal
- Norwegian Veterinary Institute (NVI), Ullevålsveien, 68, Pb 750 Sentrum, N-0106 Oslo, Norway
| | - Siv Skeie
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, N-1432 Ås, Norway
| | - Knut Rudi
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, N-1432 Ås, Norway
| | - Davide Porcellato
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, N-1432 Ås, Norway
| | - Benjamin Félix
- French Agency for Food, Environmental and Occupational Health and Safety, 14 rue Pierre et Marie Curie, 94701 Maisons-Alfort, Paris, France
| | - Judith A Narvhus
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, N-1432 Ås, Norway
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49
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Trmčić A, Chauhan K, Kent DJ, Ralyea RD, Martin NH, Boor KJ, Wiedmann M. Coliform detection in cheese is associated with specific cheese characteristics, but no association was found with pathogen detection. J Dairy Sci 2016; 99:6105-6120. [PMID: 27289158 DOI: 10.3168/jds.2016-11112] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 05/02/2016] [Indexed: 11/19/2022]
Abstract
Coliform detection in finished products, including cheese, has traditionally been used to indicate whether a given product has been manufactured under unsanitary conditions. As our understanding of the diversity of coliforms has improved, it is necessary to assess whether coliforms are a good indicator organism and whether coliform detection in cheese is associated with the presence of pathogens. The objective of this study was (1) to evaluate cheese available on the market for presence of coliforms and key pathogens, and (2) to characterize the coliforms present to assess their likely sources and public health relevance. A total of 273 cheese samples were tested for presence of coliforms and for Salmonella, Staphylococcus aureus, Shiga toxin-producing Escherichia coli, Listeria monocytogenes, and other Listeria species. Among all tested cheese samples, 27% (75/273) tested positive for coliforms in concentrations >10cfu/g. Pasteurization, pH, water activity, milk type, and rind type were factors significantly associated with detection of coliforms in cheese; for example, a higher coliform prevalence was detected in raw milk cheeses (42% with >10cfu/g) compared with pasteurized milk cheese (21%). For cheese samples contaminated with coliforms, only water activity was significantly associated with coliform concentration. Coliforms isolated from cheese samples were classified into 13 different genera, including the environmental coliform genera Hafnia, Raoultella, and Serratia, which represent the 3 genera most frequently isolated across all cheeses. Escherichia, Hafnia, and Enterobacter were significantly more common among raw milk cheeses. Based on sequencing of the housekeeping gene clpX, most Escherichia isolates were confirmed as members of fecal commensal clades of E. coli. All cheese samples tested negative for Salmonella, Staph. aureus, and Shiga toxin-producing E. coli. Listeria spp. were found in 12 cheese samples, including 5 samples positive for L. monocytogenes. Although no association was found between coliform and Listeria spp. detection, Listeria spp. were significantly more likely to be detected in cheese with the washed type of rind. Our data provide information on specific risk factors for pathogen detection in cheese, which will facilitate development of risk-based strategies to control microbial food safety hazards in cheese, and suggest that generic coliform testing cannot be used to assess the safety of natural cheese.
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Affiliation(s)
- A Trmčić
- Milk Quality Improvement Program, Department of Food Science, Cornell University, Ithaca, NY 14850
| | - K Chauhan
- Milk Quality Improvement Program, Department of Food Science, Cornell University, Ithaca, NY 14850
| | - D J Kent
- Milk Quality Improvement Program, Department of Food Science, Cornell University, Ithaca, NY 14850
| | - R D Ralyea
- Milk Quality Improvement Program, Department of Food Science, Cornell University, Ithaca, NY 14850
| | - N H Martin
- Milk Quality Improvement Program, Department of Food Science, Cornell University, Ithaca, NY 14850
| | - K J Boor
- Milk Quality Improvement Program, Department of Food Science, Cornell University, Ithaca, NY 14850
| | - M Wiedmann
- Milk Quality Improvement Program, Department of Food Science, Cornell University, Ithaca, NY 14850.
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