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Bacteriocins are ribosomal-synthesized antimicrobial peptides that inhibit the growing of pathogenic and/or deteriorating bacteria. The most studied bacteriocin-producing microorganisms are lactic acid bacteria (LAB), as they have great potential application in food biopreservation, since the majority have GRAS (Generally Recognized as Safe) status. The LAB-producing bacteriocins and/or bacteriocins produced by these bacteria have been widely studied, with the emphasis on those derived from milk and dairy products. On the other hand, isolates from meat and meat products are less studied. The objective of this review is to address the main characteristics, classification, and mechanism of action of bacteriocins and their use in food, to highlight studies on the isolation of LAB with bacteriocinogenic potential from meat and meat products and also to characterize, purify, and apply these bacteriocins in meat products. In summary, most of the microorganisms studied areLactococcus,Enterococcus,Pediococcus, andLactobacillus, which produce bacteriocins such as nisin, enterocin, pediocin, pentocin, and sakacin, many with the potential for use in food biopreservation.

Many microorganisms from various sources may be present in ejaculates of bulls. This study identified and isolated bacteria from bull sperm samples in a commercial stud and evaluated their resistance to antibiotics. The number of colony-forming units was determined in semen samples collected at distinct steps during freezing and thawing. The minimum inhibitory concentration and the minimum bactericidal concentration were determined for four antibiotics commonly used in commercial studs. A total of 135 microorganisms from 25 genera were isolated. After a sensitivity test, all evaluated microorganisms (n = 55) were resistant to penicillin and most of them were resistant to tylosin and lincomycin (n = 54). Resistance to all tested antibiotics was observed in 22% of all isolates, whereas only 3.9% of the isolates were inhibited by the tested antibiotics at the concentrations recommended by the international legislation. As the isolated microorganisms presented high resistance to frequently used antibiotics, sensitivity tests should be periodically conducted in commercial bull semen studs to prevent the use of contaminated semen in artificial insemination.

Considering the specific biochemical composition of buffalo (Bubalus bubalis) meat (high iron content, high biological value proteins and essential fatty acids, low amounts of fat and cholesterol), we evaluated the influence of cutting and deboning operations on the microbiological quality and shelf-life of vacuum-packed buffalo meat stored under refrigeration. On the processing day, samples were collected from carcass, deboning room surfaces and meat cuts. Samples from meat cuts were evaluated weekly for two months. On the processing day, higher counts of Pseudomonas spp. were observed in samples from meat cuts compared with the hindquarters and the processing surfaces. For thermotolerant coliform scores, the averages were -0.5 log MPN·cm(-2), -0.4 log MPN·cm(-2) and 0.9 log MPN·g(-1), respectively. Higher counts of Pseudomonas spp. and LAB in meat cuts were observed on the processing day and after the first week of storage, respectively, remaining constant during shelf life. Listeria grayi was identified in two samples of hindquarters and meat cuts during storage. Listeria innocua was identified in one meat cut. In conclusion, cutting and deboning operations influence the microbiological quality and shelf life of vacuum-packed buffalo meat stored under refrigeration.

Intense manipulation during beef jerky production increases the possibility of contamination with pathogenic microorganisms. This study evaluated the contamination by thermotolerant coliforms, Escherichia coli and Salmonella spp., on processing surfaces and raw materials during beef jerky production, as well as in the final product. Thermotolerant coliforms were found on all surfaces tested and in the raw material. Escherichia coli was identified in 6.7% of the surface samples, while Salmonella spp. was found in 3.3% of the surface samples and 8.6% of raw material samples. Virulence genes were detected in Salmonella spp. isolates. One Salmonella spp. isolate was resistant to sulfonamide, while one E. coli isolate was multiresistant, including the presence of resistance genes sul2, strA, strB, tetA and tetB. The presence of coliforms demonstrates failings in hygienic-sanitary procedures. The presence of pathogenic microorganisms causing foodborne diseases in the production line indicates persistent contamination in the production plant. Although the drying process applied to beef jerky should guarantee the safety of the final product, the presence of multiresistant pathogenic microorganisms, presenting virulence genes, should be a matter of concern. Because beef jerky is a ready-to-eat product, a failure in the production process may cause such microorganisms to pose a public health risk.