1
|
Asfaw T, Genetu D, Shenkute D, Shenkutie TT, Amare YE, Habteweld HA, Yitayew B. Pathogenic Bacteria and Their Antibiotic Resistance Patterns in Milk, Yoghurt and Milk Contact Surfaces in Debre Berhan Town, Ethiopia. Infect Drug Resist 2023; 16:4297-4309. [PMID: 37424670 PMCID: PMC10327909 DOI: 10.2147/idr.s418793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Accepted: 06/27/2023] [Indexed: 07/11/2023] Open
Abstract
Background Bacterial contamination of milk is a primary culprit for causing foodborne illnesses, presenting a significant health hazard for millions of individuals around the globe. The level and variety of microorganisms present in raw milk determine its degree of contamination and the potential health risks it poses. Methods A cross-sectional survey was conducted from February to August. A questionnaire was used to collect data on socio-demographic characteristics and hygiene practices from milk distributors and traders. Raw milk, yoghurt, swabs from milk containers and drinking cups were collected and processed for bacterial isolation and identification, antibiotic susceptibility testing, MDR screening and confirmation, ESBL screening and confirmation. Finally, all data were pooled and analyzed using SPSS software version 25. Results A total of 120 samples of fresh milk, yogurt and cotton swabs from milk containers and cups were collected. A total of 80 bacterial isolates were isolated from 120 samples. Among the bacteria isolated, S. aureus 17 (21.3%), E. coli 17 (21.3%), S. epidermidis 14 (17.5%), Klebsiella spp. 9 (11.3%) and Salmonella spp. 7 (8.8%) were detected most often. High rate of contamination was observed in fresh milk 23 (28.8%) and yogurt 23 (28.8%). All isolates were resistant to at least one antibiotic tested. Comparatively, high rates of resistance were observed in all isolates to the most commonly prescribed antibiotics in Ethiopia. However, lower rates of resistance have been observed for recently introduced antibiotics in Ethiopia. Of the isolates, 20 (25.0%) were resistant to eight or more antibiotics. While 16 (20.0%), 12 (15.0%), 9 (11.3%) isolates were resistant to two, three and five antibiotics, respectively. Of the bacteria isolated, 52/80 (65.0%) were MDR, 25/49 (51.0%) were screened for ESBL production, and 20/49 (40.8%) isolates were confirmed as ESBL producer. Conclusion This study showed a high rate of bacterial isolates along with MDR and ESBL-producing strains in raw milk, yoghurt, milk container swabs and drinking cup swab samples, associated with poor hygiene and sanitation practices.
Collapse
Affiliation(s)
- Tsegahun Asfaw
- Department of Medical Laboratory Science, Debre Berhan University, Debre Berhan, Ethiopia
| | - Deribew Genetu
- Department of Medical Laboratory Science, Injibara University, Injibara, Ethiopia
| | - Demissew Shenkute
- Department of Medical Laboratory Science, Debre Berhan University, Debre Berhan, Ethiopia
| | | | - Yosef Eshetie Amare
- Departments of Biomedical Science, Debre Berhan University, Debre Berhan, Ethiopia
| | | | - Berhanu Yitayew
- Department of Medical Laboratory Science, Debre Berhan University, Debre Berhan, Ethiopia
| |
Collapse
|
2
|
Martin NH, Evanowski RL, Wiedmann M. Invited review: Redefining raw milk quality-Evaluation of raw milk microbiological parameters to ensure high-quality processed dairy products. J Dairy Sci 2023; 106:1502-1517. [PMID: 36631323 DOI: 10.3168/jds.2022-22416] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Accepted: 09/17/2022] [Indexed: 01/11/2023]
Abstract
Raw milk typically has little bacterial contamination as it leaves the udder of the animal; however, through a variety of pathways, it can become contaminated with bacteria originating from environmental sources, the cow herself, and contact with contaminated equipment. Although the types of bacteria found in raw milk are very diverse, select groups are particularly important from the perspective of finished product quality. In particular, psychrophilic and psychrotolerant bacteria that grow quickly at low temperatures (e.g., species in the genus Pseudomonas and the family Enterobacteriaceae) and produce heat-stable enzymes, and sporeforming bacteria that survive processing hurdles in spore form, are the 2 primary groups of bacteria related to effects on processed dairy products. Understanding factors leading to the presence of these important bacterial groups in raw milk is key to reducing their influence on processed dairy product quality. Here we examine the raw milk microbiological parameters used in the contemporary dairy industry for their utility in identifying raw milk supplies that will perform well in processed dairy products. We further recommend the use of a single microbiological indicator of raw milk quality, namely the total bacteria count, and call for the development of a whole-farm approach to raw milk quality that will use data-driven, risk-based tools integrated across the continuum from production to processing and shelf-life to ensure continuous improvement in dairy product quality.
Collapse
Affiliation(s)
- N H Martin
- Milk Quality Improvement Program, Department of Food Science, Cornell University, Ithaca, NY 14853.
| | - R L Evanowski
- Milk Quality Improvement Program, Department of Food Science, Cornell University, Ithaca, NY 14853
| | - M Wiedmann
- Milk Quality Improvement Program, Department of Food Science, Cornell University, Ithaca, NY 14853
| |
Collapse
|
3
|
Juliano LCB, Gouvêa FLR, Latosinski GS, Fabri FHH, Salvador TB, Guimaraes FF, Ribeiro MG, Langoni H, Rall VLM, Hernandes RT, Leite DS, Pantoja JCF. Species diversity and antimicrobial resistance patterns of Enterococcus spp. isolated from mastitis cases, milking machine and the environment of dairy cows. Lett Appl Microbiol 2022; 75:924-932. [PMID: 35707938 DOI: 10.1111/lam.13768] [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: 04/26/2022] [Revised: 06/08/2022] [Accepted: 06/10/2022] [Indexed: 10/18/2022]
Abstract
The objectives were to study the diversity of Enterococcus spp. isolated from mastitis cases, milking equipment and the environment of dairy cows; and to determine in vitro resistance of isolates to antimicrobials that are relevant to human and animal health. Ten dairy farms were visited to collect samples from mastitis cases, faeces, bedding, aisles, water and milking equipment. Identification of Enterococcus at the species level and antimicrobial resistance testing was performed by MALDI-TOF and the disk-diffusion method, respectively. Of 365 isolates, Enterococcus hirae was the most prevalent, being more likely to be isolated from faeces than from milk (odds ratio (OR) = 39·2), liners (OR = 5·4) or bedding (OR = 2·2). Enterococcus saccharolyticus was the most prevalent in milk samples. The chances of isolating Enterococcus faecalis from milk were higher than from aisles (OR = 12·5), faeces (OR = 5·3), bedding (OR = 3·6) or liners (OR = 3·0). The odds of isolating Enterococcus faecium from faeces were higher than from liners (OR = 7·3), bedding (OR = 2·5) or aisles (OR = 2·4). Of 360 tested isolates, 1·9, 0·3 and 0·6% were resistant to penicillin, vancomycin and teicoplanin, respectively. Our results suggest that Enterococcus species can occupy specific ecological niches on dairy farms and pose a risk to public and animal health.
Collapse
Affiliation(s)
- L C B Juliano
- Department of Animal Production and Preventive Veterinary Medicine, Sao Paulo State University (UNESP), Botucatu, SP, Brazil
| | - F L R Gouvêa
- Department of Animal Production and Preventive Veterinary Medicine, Sao Paulo State University (UNESP), Botucatu, SP, Brazil
| | - G S Latosinski
- Department of Animal Production and Preventive Veterinary Medicine, Sao Paulo State University (UNESP), Botucatu, SP, Brazil
| | - F H H Fabri
- Department of Animal Production and Preventive Veterinary Medicine, Sao Paulo State University (UNESP), Botucatu, SP, Brazil
| | - T B Salvador
- Department of Animal Production and Preventive Veterinary Medicine, Sao Paulo State University (UNESP), Botucatu, SP, Brazil
| | - F F Guimaraes
- Department of Animal Production and Preventive Veterinary Medicine, Sao Paulo State University (UNESP), Botucatu, SP, Brazil
| | - M G Ribeiro
- Department of Animal Production and Preventive Veterinary Medicine, Sao Paulo State University (UNESP), Botucatu, SP, Brazil
| | - H Langoni
- Department of Animal Production and Preventive Veterinary Medicine, Sao Paulo State University (UNESP), Botucatu, SP, Brazil
| | - V L M Rall
- Department of Chemical and Biological Sciences, Institute of Biosciences, Sao Paulo State University (UNESP), Botucatu, SP, Brazil
| | - R T Hernandes
- Department of Chemical and Biological Sciences, Institute of Biosciences, Sao Paulo State University (UNESP), Botucatu, SP, Brazil
| | - D S Leite
- Department of Genetics, Evolution, Microbiology, and Immunology, University of Campinas, Campinas, SP, Brazil
| | - J C F Pantoja
- Department of Animal Production and Preventive Veterinary Medicine, Sao Paulo State University (UNESP), Botucatu, SP, Brazil
| |
Collapse
|
4
|
Enhancement of Labneh Quality by Laser-Induced Modulation of Lactocaseibacillus casei NRRL B-1922. FERMENTATION-BASEL 2022. [DOI: 10.3390/fermentation8030132] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Labneh is positioned in the top ranking of the bestselling dairy products all over the world due to its health benefits and delicious taste. Labneh production depends mainly on probiotic bacteria in the fermentation of milk. Probiotic bacteria have many health benefits, which are driven by their selective bioactive metabolites that quantitively affect the fermentation products. The current investigation aimed to study the implementation of photobiomodulation through the irradiation of Lacticaseibacillus casei NRRL-B-1922 by a He–Ne laser (630 nm) with different laser doses (3, 6 & 12 J/cm2) prior to milk fermentation. This procedure sought to improve the probiotic bacteria’s activities while enhancing the labneh’s characteristics and consequently produce a more favorable labneh product with better marketing qualities. The photobiostimulated bacterial starter was found to induce increased titratable acidity with the moisture reduction of the labneh product under cold storage conditions for 20 days. The effect was most prominent when using a 12 J/cm2 laser dose. The flavor-aiding components, mainly diacetyl and acetaldehyde compounds, and sensory scores were increased in the labneh produced by irradiated L. casei when compared to the non-radiated probiotic culture after storing the products under cold conditions for 20 consecutive days. Moreover, the antioxidant and proteolytic activities of labneh produced by treated L. casei (12 J/cm2 laser dose) after cold storage were significantly elevated by 41 and 14%, respectively. In conclusion, we can report significantly improved selected characteristics in the final products after the employment of photobiomodulation process, the potential application of this concept on the industrial scale, and its implications on lengthening the product shelf life with improved qualities.
Collapse
|
5
|
Souad R, Mossadak HT, Leila B. Assessing hygiene indicators in two dairies in Algeria in producing pasteurized milk. Vet World 2021; 14:2317-2324. [PMID: 34840449 PMCID: PMC8613772 DOI: 10.14202/vetworld.2021.2317-2324] [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: 04/09/2021] [Accepted: 07/28/2021] [Indexed: 11/16/2022] Open
Abstract
Background and Aim: There is a worldwide controversy about the choice of microbial flora for use as process hygiene indicators. This study aimed to evaluate the pertinence of using either coliforms or Enterobacteriaceae (EB) as process hygiene indicators in the pasteurized milk production line. Two flora families and total flora were used as bacterial indicators in some stages of pasteurized milk production line to identify the origin of post-pasteurization contamination and compare the results obtained for each flora. In addition, the bacteriological profile of isolated coliforms and EB was developed. Materials and Methods: One thousand and two hundred samples of pasteurized cow milk and surfaces (pipes and tank) at various processing stages were taken from two dairies in the northern region of Algeria. The total microbial flora (TF), total coliforms (TC), thermotolerant coliforms, and EB were enumerated, following the recommendations of ISO 4833:2006, ISO 4832:2006, and ISO 21528-2:2017 methods, respectively. The bacteriological profile was determined using the API 20E and 10S tests (bioMérieux, France). Furthermore, the cleaning efficiency and disinfection protocol of surfaces were evaluated using contact agar slides 1 (Liofilchem™, Italy). Results: Enumeration of the different indicators shows that the highest contamination rate is recorded by the total flora in the two units, 3.28 and 3.78 log CFU/mL, respectively. EB (−0.60 log CFU/mL) at post-pasteurization stage in Unit 1 and coliforms (0.44 log CFU/mL) at the pasteurized packaged milk stage in Unit 2 are the least significant germ families. The lowest compliance rates of bacterial contamination were reported for total flora (82-85%) at the three sampled sites in Unit 2. In comparison, the highest was reported in Unit 1 (99.8%) and 2 (98%) by the EB indicator. Assessing the surface cleaning and disinfection protocol compliance shows that the tank records the highest non-compliance rates for EB and TF (4% and 3%) in Unit 2. EB are represented in both units by various species. Acinetobacter baumannii in Unit 1 and Enterobacter cloacae in Unit 2 are the common species of the three indicator families. Acinetobacter and Enterobacter in Unit 1, Escherichia, Citrobacter, Enterobacter, Klebsiella, and Hafnia in Unit 2 are the most time persistent bacterial genera along the production line. Stenotrophomonas, Serratia, Salmonella, Enterobacter, and Escherichia are common genera in both units. Conclusion: The results obtained show no difference in the use of EB or TC as hygiene indicators. However, if the objective is to identify the species of bacterial populations, using EBs are the most appropriate.
Collapse
Affiliation(s)
- Regguem Souad
- Laboratory of Food Hygiene and Quality Insurance System (HASAQ), Higher National Veterinary School, Rue Issad Abbes, Oued Smar, Algiers 16000, Algeria
| | - Hamdi Taha Mossadak
- Laboratory of Food Hygiene and Quality Insurance System (HASAQ), Higher National Veterinary School, Rue Issad Abbes, Oued Smar, Algiers 16000, Algeria
| | - Bouayad Leila
- Laboratory of Food Hygiene and Quality Insurance System (HASAQ), Higher National Veterinary School, Rue Issad Abbes, Oued Smar, Algiers 16000, Algeria
| |
Collapse
|
6
|
Suwono B, Eckmanns T, Kaspar H, Merle R, Zacher B, Kollas C, Weiser AA, Noll I, Feig M, Tenhagen BA. Cluster analysis of resistance combinations in Escherichia coli from different human and animal populations in Germany 2014-2017. PLoS One 2021; 16:e0244413. [PMID: 33471826 PMCID: PMC7817003 DOI: 10.1371/journal.pone.0244413] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 12/09/2020] [Indexed: 11/18/2022] Open
Abstract
Recent findings on Antibiotic Resistance (AR) have brought renewed attention to the comparison of data on AR from human and animal sectors. This is however a major challenge since the data is not harmonized. This study performs a comparative analysis of data on resistance combinations in Escherichia coli (E. coli) from different routine surveillance and monitoring systems for human and different animal populations in Germany. Data on E. coli isolates were collected between 2014 and 2017 from human clinical isolates, non-clinical animal isolates from food-producing animals and food, and clinical animal isolates from food-producing and companion animals from national routine surveillance and monitoring for AR in Germany. Sixteen possible resistance combinations to four antibiotics—ampicillin, cefotaxime, ciprofloxacin and gentamicin–for these populations were used for hierarchical clustering (Euclidian and average distance). All analyses were performed with the software R 3.5.1 (Rstudio 1.1.442). Data of 333,496 E. coli isolates and forty-one different human and animal populations were included in the cluster analysis. Three main clusters were detected. Within these three clusters, all human populations (intensive care unit (ICU), general ward and outpatient care) showed similar relative frequencies of the resistance combinations and clustered together. They demonstrated similarities with clinical isolates from different animal populations and most isolates from pigs from both non-clinical and clinical isolates. Isolates from healthy poultry demonstrated similarities in relative frequencies of resistance combinations and clustered together. However, they clustered separately from the human isolates. All isolates from different animal populations with low relative frequencies of resistance combinations clustered together. They also clustered separately from the human populations. Cluster analysis has been able to demonstrate the linkage among human isolates and isolates from various animal populations based on the resistance combinations. Further analyses based on these findings might support a better one-health approach for AR in Germany.
Collapse
Affiliation(s)
- Beneditta Suwono
- Department Biological Safety, Unit Epidemiology, Zoonoses and Antimicrobial Resistance, German Federal Institute for Risk Assessment, Berlin, Germany
- Department Infectious Disease Epidemiology, Unit Healthcare-associated Infections, Surveillance for Antibiotic Resistance and Consumption, Robert Koch Institute, Berlin, Germany
| | - Tim Eckmanns
- Department Infectious Disease Epidemiology, Unit Healthcare-associated Infections, Surveillance for Antibiotic Resistance and Consumption, Robert Koch Institute, Berlin, Germany
| | - Heike Kaspar
- Unit Antibiotic Resistance Monitoring, Federal Office of Consumer Protection and Food Safety, Berlin, Germany
| | - Roswitha Merle
- Department of Veterinary Medicine, Institute for Veterinary Epidemiology and Biostatistics, Working Group Applied Epidemiology, Free University Berlin, Berlin, Germany
| | - Benedikt Zacher
- Department Infectious Disease Epidemiology, Unit Healthcare-associated Infections, Surveillance for Antibiotic Resistance and Consumption, Robert Koch Institute, Berlin, Germany
| | - Chris Kollas
- Department Biological Safety, Unit Epidemiology, Zoonoses and Antimicrobial Resistance, German Federal Institute for Risk Assessment, Berlin, Germany
| | - Armin A. Weiser
- Department Biological Safety, Unit Epidemiology, Zoonoses and Antimicrobial Resistance, German Federal Institute for Risk Assessment, Berlin, Germany
| | - Ines Noll
- Department Infectious Disease Epidemiology, Unit Healthcare-associated Infections, Surveillance for Antibiotic Resistance and Consumption, Robert Koch Institute, Berlin, Germany
| | - Marcel Feig
- Department Infectious Disease Epidemiology, Unit Healthcare-associated Infections, Surveillance for Antibiotic Resistance and Consumption, Robert Koch Institute, Berlin, Germany
| | - Bernd-Alois Tenhagen
- Department Biological Safety, Unit Epidemiology, Zoonoses and Antimicrobial Resistance, German Federal Institute for Risk Assessment, Berlin, Germany
- * E-mail:
| |
Collapse
|
7
|
Berhe G, Wasihun AG, Kassaye E, Gebreselasie K. Milk-borne bacterial health hazards in milk produced for commercial purpose in Tigray, northern Ethiopia. BMC Public Health 2020; 20:894. [PMID: 32517771 PMCID: PMC7285727 DOI: 10.1186/s12889-020-09016-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 05/29/2020] [Indexed: 11/18/2022] Open
Abstract
Background Milk being a suitable medium for bacterial growth, it can serve as a source of bacterial contamination. Pathogenic bacteria in milk pose a serious health threat to humans and constitute about 90% of all dairy-related diseases. However, there are few studies that examined the health hazards of raw milk consumption in Ethiopia. Therefore, the objective of this study was to assess the prevalence of bacterial contamination and associated factors in milk produced for commercial purpose in Tigray region, northern Ethiopia. Methods This study used a cross-sectional study design, selected 315 persons (168 cafeterias, 96 dairy farms, and 51 milk vendors) for interview and collected the same number of bulk raw milk samples using systematic sampling procedure. Data were collected on socio-demographic, farm hygiene and milk handling practices by trained health professionals. Bacterial contamination was defined as total bacterial count (TBC) > 1 × 105, staphylococcus count (SC) > 105, or coliform count (CC) > 102 CFU/ml by culture and the species of bacteria were determined by standard biochemical tests. Results From the 315 milk samples tested, the prevalence of bacterial contamination was 52% (95% CI: 46.5–57.6). The mean counts of contaminated samples of TBC, SC, and CC were 8.94 ± 0.46 Standard Deviation (SD), 8.52 ± 0.6 SD, and 8.78 ± 0.49 SD log CFU/ml, respectively. The proportion of contamination was significantly lower in milk collected from dairy farms (32/96, 33.3, 95% CI: 24.5–43.2) compared to milk from vendors (33/51, 64.7, 95% CI: 51.4–66.2) and cafeterias (99/168, 58.9, 95% CI, 50.9–76.85). The milk samples were culture-positive for Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, K. oxytoca and Citrobacter freundii. Conclusions Over half of the sampled raw milk exhibited bacterial contamination with increasing trend from farmers to points of sale. Thus, milk vendors and cafeteria owners should apply good hygienic and sanitation practices during handling of milk; use appropriate, clean containers, and cold chain during milk transportation; and refrigeration of milk during storage.
Collapse
|
8
|
Effect of Structural Condition of Milk Processing Facilities and Food Safety Systems on Escherichia coli and Coliforms Presence in Cultured Buttermilk. J FOOD QUALITY 2019. [DOI: 10.1155/2019/7365983] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The study investigated the effect of structural conditions of milk processing facilities and food safety systems on E. coli and coliform presence in buttermilk. Milk records collected by Dairy Services Zimbabwe (DSZ) from large-scale dairy milk processors (n=12) and small-scale farms (n=15) were analysed. Binomial logistic regression was used to estimate the likelihood of E. coli or coliforms being present in cultured buttermilk as a function of the hygiene level and structural adequacy of the processors. The likelihood of having E. coli and coliforms in cultured milk from processors with poor sanitary premises was two times higher than that from processors with good sanitary premises (P<0.05). Milk processors that used unfiltered water were 1.77 times more likely to produce cultured buttermilk contaminated with E. coli (P<0.05). Processors without food safety systems like hazard analysis critical control point (HACCP) systems were more than twice likely to produce cultured buttermilk contaminated by E. coli and coliforms (P<0.05). Poor structural condition of roofs, windows, insect-proof screens, and drainage in small- and large-scale processing facilities results in production of cultured buttermilk that is contaminated by E. coli and coliforms.
Collapse
|
9
|
Use of geographical information system and ecological niche modelling for predicting potential space distribution of subclinical mastitis in ewes. Vet Microbiol 2019; 228:119-128. [DOI: 10.1016/j.vetmic.2018.11.021] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2018] [Revised: 11/13/2018] [Accepted: 11/20/2018] [Indexed: 02/02/2023]
|
10
|
Vasileiou N, Chatzopoulos D, Gougoulis D, Sarrou S, Katsafadou A, Spyrou V, Mavrogianni V, Petinaki E, Fthenakis G. Slime-producing staphylococci as causal agents of subclinical mastitis in sheep. Vet Microbiol 2018; 224:93-99. [DOI: 10.1016/j.vetmic.2018.08.022] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 08/22/2018] [Accepted: 08/22/2018] [Indexed: 11/28/2022]
|
11
|
McHugh AJ, Feehily C, Hill C, Cotter PD. Detection and Enumeration of Spore-Forming Bacteria in Powdered Dairy Products. Front Microbiol 2017; 8:109. [PMID: 28197144 PMCID: PMC5281614 DOI: 10.3389/fmicb.2017.00109] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 01/16/2017] [Indexed: 01/28/2023] Open
Abstract
With the abolition of milk quotas in the European Union in 2015, several member states including Ireland, Luxembourg, and Belgium have seen year on year bi-monthly milk deliveries to dairies increase by up to 35%. Milk production has also increased outside of Europe in the past number of years. Unsurprisingly, there has been a corresponding increased focus on the production of dried milk products for improved shelf life. These powders are used in a wide variety of products, including confectionery, infant formula, sports dietary supplements and supplements for health recovery. To ensure quality and safety standards in the dairy sector, strict controls are in place with respect to the acceptable quantity and species of microorganisms present in these products. A particular emphasis on spore-forming bacteria is necessary due to their inherent ability to survive extreme processing conditions. Traditional microbiological detection methods used in industry have limitations in terms of time, efficiency, accuracy, and sensitivity. The following review will explore the common spore-forming bacterial contaminants of milk powders, will review the guidelines with respect to the acceptable limits of these microorganisms and will provide an insight into recent advances in methods for detecting these microbes. The various advantages and limitations with respect to the application of these diagnostics approaches for dairy food will be provided. It is anticipated that the optimization and application of these methods in appropriate ways can ensure that the enhanced pressures associated with increased production will not result in any lessening of safety and quality standards.
Collapse
Affiliation(s)
- Aoife J McHugh
- Food Bioscience Department, Teagasc Food Research CentreCork, Ireland; School of Microbiology, University College CorkCork, Ireland
| | - Conor Feehily
- Food Bioscience Department, Teagasc Food Research CentreCork, Ireland; APC Microbiome InstituteCork, Ireland
| | - Colin Hill
- School of Microbiology, University College CorkCork, Ireland; APC Microbiome InstituteCork, Ireland
| | - Paul D Cotter
- Food Bioscience Department, Teagasc Food Research CentreCork, Ireland; APC Microbiome InstituteCork, Ireland
| |
Collapse
|
12
|
Martin NH, Trmčić A, Hsieh TH, Boor KJ, Wiedmann M. The Evolving Role of Coliforms As Indicators of Unhygienic Processing Conditions in Dairy Foods. Front Microbiol 2016; 7:1549. [PMID: 27746769 PMCID: PMC5043024 DOI: 10.3389/fmicb.2016.01549] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 09/15/2016] [Indexed: 11/24/2022] Open
Abstract
Testing for coliforms has a long history in the dairy industry and has helped to identify raw milk and dairy products that may have been exposed to unsanitary conditions. Coliform standards are included in a number of regulatory documents (e.g., the U.S. Food and Drug Administration's Grade "A" Pasteurized Milk Ordinance). As a consequence, detection above a threshold of members of this method-defined, but diverse, group of bacteria can result in a wide range of regulatory outcomes. Coliforms are defined as aerobic or facultatively anaerobic, Gram negative, non-sporeforming rods capable of fermenting lactose to produce gas and acid within 48 h at 32-35°C; 19 genera currently include at least some strains that represent coliforms. Most bacterial genera that comprise the coliform group (e.g., Escherichia, Klebsiella, and Serratia) are within the family Enterobacteriaceae, while at least one genus with strains recognized as coliforms, Aeromonas, is in the family Aeromonadaceae. The presence of coliforms has long been thought to indicate fecal contamination, however, recent discoveries regarding this diverse group of bacteria indicates that only a fraction are fecal in origin, while the majority are environmental contaminants. In the US dairy industry in particular, testing for coliforms as indicators of unsanitary conditions and post-processing contamination is widespread. While coliforms are easily and rapidly detected, and are not found in pasteurized dairy products that have not been exposed to post-processing contamination, advances in knowledge of bacterial populations most commonly associated with post-processing contamination in dairy foods has led to questions regarding the utility of coliforms as indicators of unsanitary conditions for dairy products. For example, Pseudomonas spp. frequently contaminate dairy products after pasteurization, yet they are not detected by coliform tests. This review will address the role that coliforms play in raw and finished dairy products, their sources and the future of this diverse group as indicator organisms in dairy products.
Collapse
Affiliation(s)
- Nicole H. Martin
- Milk Quality Improvement Program, Department of Food Science, Cornell UniversityIthaca, NY, USA
| | | | | | | | | |
Collapse
|
13
|
Kable ME, Srisengfa Y, Laird M, Zaragoza J, McLeod J, Heidenreich J, Marco ML. The Core and Seasonal Microbiota of Raw Bovine Milk in Tanker Trucks and the Impact of Transfer to a Milk Processing Facility. mBio 2016; 7:e00836-16. [PMID: 27555305 PMCID: PMC4999540 DOI: 10.1128/mbio.00836-16] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Accepted: 07/25/2016] [Indexed: 02/01/2023] Open
Abstract
UNLABELLED Currently, the bacterial composition of raw milk in tanker trucks and the outcomes of transfer and storage of that milk at commercial processing facilities are not well understood. We set out to identify the bacteria in raw milk collected for large-scale dairy product manufacturing. Raw bovine milk samples from 899 tanker trucks arriving at two dairy processors in San Joaquin Valley of California during three seasons (spring, summer, and fall) were analyzed by community 16S rRNA gene sequencing. This analysis revealed highly diverse bacterial populations, which exhibited seasonal differences. Raw milk collected in the spring contained the most diverse bacterial communities, with the highest total cell numbers and highest proportions being those of Actinobacteria Even with this complexity, a core microbiota was present, consisting of 29 taxonomic groups and high proportions of Streptococcus and Staphylococcus and unidentified members of Clostridiales Milk samples were also collected from five large-volume silos and from 13 to 25 tankers whose contents were unloaded into each of them during 2 days in the summer. Transfer of the milk to storage silos resulted in two community types. One group of silos contained a high proportion of Streptococcus spp. and was similar in that respect to the tankers that filled them. The community found in the other group of silos was distinct and dominated by Acinetobacter Overall, despite highly diverse tanker milk community structures, distinct milk bacterial communities were selected within the processing facility environment. This knowledge can inform the development of new sanitation procedures and process controls to ensure the consistent production of safe and high-quality dairy products on a global scale. IMPORTANCE Raw milk harbors diverse bacteria that are crucial determinants of the quality and safety of fluid milk and (fermented) dairy products. These bacteria enter farm milk during transport, storage, and processing. Although pathogens are destroyed by pasteurization, not all bacteria and their associated enzymes are eliminated. Our comprehensive analyses of the bacterial composition of raw milk upon arrival and shortly after storage at major dairy processors showed that the communities of milk microbiota are highly diverse. Even with these differences, there was a core microbiota that exhibited distinct seasonal trends. Remarkably, the effects of the processing facility outweighed those of the raw milk microbiome and the microbial composition changed distinctly within some but not all silos within a short time after transfer. This knowledge can be used to inform cleaning and sanitation procedures as well as to enable predictions of the microbial communities in raw milk that result in either high-quality or defective products.
Collapse
Affiliation(s)
- Mary E Kable
- Department of Food Science and Technology, University of California Davis, Davis, California, USA
| | - Yanin Srisengfa
- Department of Food Science and Technology, University of California Davis, Davis, California, USA
| | - Miles Laird
- Department of Food Science and Technology, University of California Davis, Davis, California, USA
| | - Jose Zaragoza
- Department of Food Science and Technology, University of California Davis, Davis, California, USA
| | | | | | - Maria L Marco
- Department of Food Science and Technology, University of California Davis, Davis, California, USA
| |
Collapse
|
14
|
Weber M, Geißert J, Kruse M, Lipski A. Comparative analysis of bacterial community composition in bulk tank raw milk by culture-dependent and culture-independent methods using the viability dye propidium monoazide. J Dairy Sci 2014; 97:6761-76. [DOI: 10.3168/jds.2014-8340] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Accepted: 08/01/2014] [Indexed: 11/19/2022]
|
15
|
Piepers S, Zrimšek P, Passchyn P, De Vliegher S. Manageable risk factors associated with bacterial and coliform counts in unpasteurized bulk milk in Flemish dairy herds. J Dairy Sci 2014; 97:3409-19. [DOI: 10.3168/jds.2013-7203] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2013] [Accepted: 02/24/2014] [Indexed: 11/19/2022]
|
16
|
|
17
|
Nagy P, Faye B, Marko O, Thomas S, Wernery U, Juhasz J. Microbiological quality and somatic cell count in bulk milk of dromedary camels (Camelus dromedarius): Descriptive statistics, correlations, and factors of variation. J Dairy Sci 2013; 96:5625-40. [DOI: 10.3168/jds.2013-6990] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Accepted: 05/17/2013] [Indexed: 11/19/2022]
|
18
|
Nóbrega DB, Guiduce MV, Guimarães FF, Riboli DF, Cunha ML, Langoni H, Pantoja JC, Lucheis SB. Molecular epidemiology and extended-spectrum β-lactamases production of Klebsiella pneumoniae isolated from three dairy herds. PESQUISA VETERINARIA BRASILEIRA 2013. [DOI: 10.1590/s0100-736x2013000700005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The objectives of this study were to isolate Klebsiella pneumoniae from different sources in three dairy cattle herds, to use the pulsed-field gel electrophoresis (PFGE) to measure genotypic similarities between isolates within a dairy herd, to verify the production of extended-spectrum β-lactamases (ESBLs) by the double-disk synergy test (DDST), and to use the PCR to detect the main ESBLs subgroups genes. Three dairy farms were selected based on previous mastitis outbreaks caused by K. pneumoniae. Milk samples were collected from lactating cows and from the bulk tank. Swabs were performed in different locations, including milking parlors, waiting room, soil, animal's hind limbs and rectum. K. pneumoniae was isolated from 27 cases of intramammary infections (IMI) and from 41 swabs. For farm A isolates from IMI and bulk tank were considered of the same PGFE subtype. One isolate from a bulk tank, three from IMI cases and four from environmental samples were positive in the DDST test. All eight DDST positive isolates harbored the bla shv gene, one harbored the bla tem gene, and three harbored the bla ctx-m gene, including the bulk tank isolate. Our study confirms that ESBL producing bacteria is present in different locations in dairy farms, and may be responsible for IMI. The detection of ESBLs on dairy herds could be a major concern for both public and animal health.
Collapse
|
19
|
Jackson EE, Erten ES, Maddi N, Graham TE, Larkin JW, Blodgett RJ, Schlesser JE, Reddy RM. Detection and enumeration of four foodborne pathogens in raw commingled silo milk in the United States. J Food Prot 2012; 75:1382-93. [PMID: 22856561 DOI: 10.4315/0362-028x.jfp-11-548] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A nationwide survey was conducted to obtain qualitative and quantitative data on bacterial contamination of raw commingled silo milk intended for pasteurization. The levels of total aerobic bacteria, total coliforms, Enterobacteriaceae, Escherichia coli, and Staphylococcus aureus were determined using the TEMPO system. The prevalence rates and levels of presumptive Bacillus cereus, E. coli O157:H7, Listeria monocytogenes, and Salmonella spp. were determined in 214 samples. B. cereus was detected in 8.91% of samples, at 3.0 to 93 CFU/ml. E. coli O157:H7 was detected in 3.79 to 9.05% of samples, at <0.0055 to 1.1 CFU/ml, depending on the assay utilized. Salmonella spp. were recovered from 21.96 to 57.94% of samples, at <0.0055 to 60 CFU/ml. L. monocytogenes was detected in 50.00% of samples, at <0.0055 to 30 CFU/ml. The average log-transformed counts of total viable bacteria were slightly lower in samples containing no pathogens. No correlation was observed between the levels of organisms detected with the TEMPO system and the presence or levels of any pathogen except E. coli O157:H7. A higher average log-transformed count of total viable bacteria was observed in samples positive for this organism. The high prevalence rates of target pathogens may be attributed to a variety of factors, including detection methods, sample size, and commingling of the milk in the silo. The effects of commingling likely contributed to the high prevalence rates and low levels of target pathogens because of the inclusion of milk from multiple bulk tanks. The high prevalence rates also may be the result of analysis of larger sample volumes using more sensitive detection methods. These quantitative data could be utilized to perform more accurate risk assessments and to better estimate the appropriate level of protection for dairy products and processing technologies.
Collapse
Affiliation(s)
- Emily E Jackson
- U.S. Food and Drug Administration, Institute for Food Safety and Health, 6502 South Archer Road, Bedford Park, Illinois 60501, USA
| | | | | | | | | | | | | | | |
Collapse
|
20
|
Abstract
The objective of this study was therefore to present factors affecting somatic cell counts in bovine bulk milk as a result of intramammary infections as well as non-infectious factors. The paper presents also the impact of on-farm management practices on the level of bulk milk somatic cell counts and presents quality indicators in bulk tank milk. At the farm level bulk milk bacterial infection takes place through three main sources: bacterial contamination from the external surface of the udder and teats, from the surface of the milking equipment, and from mastitis microorganisms within the udder. The threshold of 200,000 cells/ml identifies bacteriological negative quarters of the udder. The counts of mammary pathogens in bulk tank milk are relatively low, on average not exceeding 1,000 cfu/ml. Environmental pathogens predominate in bulk tank milk samples with somatic cells count <300 × 10(3) ml.
Collapse
Affiliation(s)
- Jan Olechnowicz
- Department of Veterinary Medicine, Faculty of Animal Breeding and Biology, Poznan University of Life Sciences, 52 Wojska Polskiego, 60-625 Poznan, Poland.
| | | |
Collapse
|