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Todaro M, Garofalo G, Busetta G, Gannuscio R, Di Rosa AR, Scatassa ML, Cardamone C, Mancuso I, Franciosi E, Rando F, Agnolucci M, Chiofalo V, Gaglio R, Settanni L. Reduction of PDO Pecorino Siciliano cheese making duration: Microbial dynamics and quality attributes deriving from replacing whey permeate with hot water during cooking. Int J Food Microbiol 2024; 410:110481. [PMID: 37977081 DOI: 10.1016/j.ijfoodmicro.2023.110481] [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: 07/26/2023] [Revised: 11/04/2023] [Accepted: 11/05/2023] [Indexed: 11/19/2023]
Abstract
This work was carried out with the aim to reduce the transformation duration of Protected Designation of Origin (PDO) Pecorino Siciliano cheese. To this purpose, the cooking in hot water (experimental production, EXP) was compared to the traditional cheese cooking under whey permeate (control production, CTR). The microbiological composition of under rind (UR) and core (Co) section of CTR and EXP cheeses was determined by a combined culture-dependent and -independent approach. Total mesophilic microorganisms and lactic acid bacteria (LAB) present in raw ewes' milk (5.0 log CFU/mL) increased during cheese making and reached values of about 8.0 log CFU/g in both sections (UR and Co) of 5-month ripened cheeses of both productions (CTR and EXP) monitored. The identification of the viable LAB populations in ripened cheeses showed that Enterococcus, Lacticaseibacillus, Lactiplantibacillus, Levilactobacillus, Limosilactobacillus and Streptococcus dominated UR and Co sections of all cheeses. MiSeq Illumina analysis demonstrated that LAB populations (lactobacilli, lactococci and streptococci) dominated the bacterial community of cheeses at 95.63-98.41 % of relative abundance. The two different cooking operations did not influence the physicochemical characteristics of PDO Pecorino Siciliano cheeses. Sensory evaluation performed by artificial senses analysis and trained panelists confirmed that the modification of PDO Pecorino Siciliano cheese production protocol did not significantly affect product characteristics and overall acceptance. Thus, data of this work confirmed that cooking under hot water allowed to reduce transformation duration and safeguard typicality of PDO Pecorino Siciliano cheese.
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Affiliation(s)
- Massimo Todaro
- Department of Agricultural, Food and Forest Sciences, University of Palermo, Viale delle Scienze, Bldg. 5, 90128 Palermo, Italy
| | - Giuliana Garofalo
- Department of Agricultural, Food and Forest Sciences, University of Palermo, Viale delle Scienze, Bldg. 5, 90128 Palermo, Italy
| | - Gabriele Busetta
- Department of Agricultural, Food and Forest Sciences, University of Palermo, Viale delle Scienze, Bldg. 5, 90128 Palermo, Italy
| | - Riccardo Gannuscio
- Department of Agricultural, Food and Forest Sciences, University of Palermo, Viale delle Scienze, Bldg. 5, 90128 Palermo, Italy
| | - Ambra Rita Di Rosa
- Department of Veterinary Sciences, University of Messina, 98168 Messina, Italy
| | - Maria Luisa Scatassa
- Institute for Experimental Veterinary Medicine of Sicily A. Mirri, 90129 Palermo, Italy
| | - Cinzia Cardamone
- Institute for Experimental Veterinary Medicine of Sicily A. Mirri, 90129 Palermo, Italy
| | - Isabella Mancuso
- Institute for Experimental Veterinary Medicine of Sicily A. Mirri, 90129 Palermo, Italy
| | - Elena Franciosi
- Research and Innovation Centre, Fondazione Edmund Mach (FEM), Via E. Mach 1, 38098 San Michele all'Adige, Italy
| | - Fatima Rando
- Institute for Experimental Veterinary Medicine of Sicily A. Mirri, 90129 Palermo, Italy; Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, Pisa 56124, Italy
| | - Monica Agnolucci
- Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, Pisa 56124, Italy
| | - Vincenzo Chiofalo
- Department of Veterinary Sciences, University of Messina, 98168 Messina, Italy
| | - Raimondo Gaglio
- Department of Agricultural, Food and Forest Sciences, University of Palermo, Viale delle Scienze, Bldg. 5, 90128 Palermo, Italy.
| | - Luca Settanni
- Department of Agricultural, Food and Forest Sciences, University of Palermo, Viale delle Scienze, Bldg. 5, 90128 Palermo, Italy
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Milani G, Belloso Daza MV, Cortimiglia C, Bassi D, Cocconcelli PS. Genome engineering of Stx1-and Stx2-converting bacteriophages unveils the virulence of the dairy isolate Escherichia coli O174:H2 strain UC4224. Front Microbiol 2023; 14:1156375. [PMID: 37426006 PMCID: PMC10326431 DOI: 10.3389/fmicb.2023.1156375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 06/06/2023] [Indexed: 07/11/2023] Open
Abstract
The past decade witnessed the emergence in Shiga toxin-producing Escherichia coli (STEC) infections linked to the consumption of unpasteurized milk and raw milk cheese. The virulence of STEC is primarily attributed to the presence of Shiga toxin genes (stx1 and stx2) carried by Stx-converting bacteriophages, along with the intimin gene eae. Most of the available information pertains to the "Top 7" serotypes associated with STEC infections. The objectives of this study were to characterize and investigate the pathogenicity potential of E. coli UC4224, a STEC O174:H2 strain isolated from semi-hard raw milk cheese and to develop surrogate strains with reduced virulence for use in food-related studies. Complete genome sequence analysis of E. coli UC4224 unveiled the presence of a Stx1a bacteriophage, a Stx2a bacteriophage, the Locus of Adhesion and Autoaggregation (LAA) pathogenicity island, plasmid-encoded virulence genes, and other colonization facilitators. In the Galleria mellonella animal model, E. coli UC4224 demonstrated high pathogenicity potential with an LD50 of 6 CFU/10 μL. Upon engineering E. coli UC4224 to generate single and double mutant derivatives by inactivating stx1a and/or stx2a genes, the LD50 increased by approximately 1 Log-dose in the single mutants and 2 Log-doses in the double mutants. However, infectivity was not completely abolished, suggesting the involvement of other virulence factors contributing to the pathogenicity of STEC O174:H2. Considering the possibility of raw milk cheese serving as a reservoir for STEC, cheesemaking model was developed to evaluate the survival of UC4224 and the adequacy of the respective mutants as reduced-virulence surrogates. All tested strains exhibited the ability to survive the curd cooking step at 48°C and multiplied (3.4 Log CFU) in cheese within the subsequent 24 h. These findings indicate that genomic engineering did not exert any unintended effect on the double stx1-stx2 mutant behaviour, making it as a suitable less-virulent surrogate for conducting studies during food processing.
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Otero V, Santos JA, Rodríguez-Calleja JM, García-López ML. Behavior of Shiga-toxin-producing Escherichia coli in ewe milk stored at different temperatures and during the manufacture and ripening of a raw milk sheep cheese (Zamorano style). J Dairy Sci 2022; 105:6527-6535. [PMID: 35717333 DOI: 10.3168/jds.2021-21613] [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: 11/23/2021] [Accepted: 04/02/2022] [Indexed: 11/19/2022]
Abstract
This study was conducted to assess the survival of 2 wild Shiga toxin-producing Escherichia coli strains (one serotype O157:H7 and one non-O157:H7) in ewe milk stored at different conditions and to examine the fate of the O157 strain during the manufacture and ripening of a Spanish sheep hard variety of raw milk cheese (Zamorano). The strains were selected among a population of 50 isolates, which we obtained from ewe milk, because of their high resistance to 0.3% lactic acid. Both strains were inoculated (approximately 2 log10 cfu/mL) in raw and heat-treated (low-temperature holding, LTH; 63°C/30 min) ewe milk and stored for 5 d at 6, 8, and 10°C and also according to a simulation approach for assessing the effects of failures in the cold chain. The minimum growth temperature for the O157:H7 strain in LTH and raw ewe milk was 8°C. For the non-O157:H7 strain, the lowest temperature showing bacterial growth in LTH ewe milk was 6°C, but it did not grow at any of the tested conditions in raw milk. It appears that the O157 strain was more susceptible to cold stress but was likely a better competitor than the non-O157 strain against the milk autochthonous microbiota. For manufacture of Zamorano cheese, raw milk was inoculated with approximately 3 log10 cfu/mL, and after 2 mo of ripening at 10 to 12°C, the cheeses showed the expected general characteristics for this variety. The O157:H7 strain increased 0.9 log10 cfu/g after whey drainage and during ripening and storage decreased by 2.9 log10 cfu/g. Nevertheless, its detectable level (estimated at 6.2 cfu/g) after 2 mo of ripening suggests that Zamorano cheese manufactured from raw ewe milk contaminated with E. coli O157:H7 could represent a public health concern.
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Affiliation(s)
- Verónica Otero
- Department of Food Hygiene and Food Technology, Veterinary Faculty, University of León, Spain 24007
| | - Jesús A Santos
- Department of Food Hygiene and Food Technology, Veterinary Faculty, University of León, Spain 24007
| | - Jose M Rodríguez-Calleja
- Department of Food Hygiene and Food Technology, Veterinary Faculty, University of León, Spain 24007.
| | - María-Luisa García-López
- Department of Food Hygiene and Food Technology, Veterinary Faculty, University of León, Spain 24007
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