The continued and improper use of antibiotics has resulted in the emergence of antibiotic resistance (AR). The dissemination of antibiotic-resistant microorganisms occurs via a multitude of pathways, including the food supply. The failure to comply with the regulatory withdrawal period associated with the treatment of domestic animals or the illicit use of antibiotics as growth promoters has contributed to the proliferation of antibiotic-resistant bacteria in meat and dairy products. It was demonstrated that not only do animal and human pathogens act as donors of antibiotic resistance genes, but also that lactic acid bacteria can serve as reservoirs of genes encoding for antibiotic resistance. Consequently, the consumption of fermented foods also presents a potential conduit for the dissemination of AR. This review provides an overview of the potential for the transmission of antibiotic resistance in a range of traditional and novel foods. The literature data reveal that foodborne microbes can be a significant factor in the dissemination of antibiotic resistance.

Serratia marcescens strains from a dairy-producing environment were tested for their inhibitory effect on Listeria monocytogenes, Salmonella Hartford, Yersinia enterocolitica and Escherichia coli. Inhibition of foodborne pathogens was observed in the case of a non-pigmented Serratia strain, while the pigment-producing isolate was able to inhibit only Y. enterocolitica. The co-culturing study in tryptone soya broth (TSB) and milk showed that the growth of Salmonella was inhibited in the first 24 h, but later the pathogen could grow in the presence of the Serratia strain even if its cell concentration was 1000 times higher than that of Salmonella. However, we found that (1) concentrated cell-free supernatants had stronger inhibitory activity, which confirms the extracellular nature of the antagonistic compound(s). We proved that (2) protease and chitinase enzymes can take part in this mechanism, but they are not the main inhibitory compounds. The presence of prodigiosin was observed only in the case of the pigmented strain; thus, (3) we hypothesized that prodigiosin does not take part in the inhibition of the pathogens. However, (4) the combined effect of different extracellular metabolites might be attributed to the inhibitory property. Application of concentrated S. marcescens cell-free supernatant can be an effective antibacterial strategy in the food industry, mainly in the form of a bio-disinfectant on surfaces of food-processing areas.

The presence of yeasts in food is not unexpected, as they are part of the microbiota of raw materials, employed as starter cultures in numerous fermentation processes, and also play a role in spontaneous fermentation. Nevertheless, they have the potential to induce spoilage, which can lead to significant quality issues, and certain yeasts have the ability to cause infections in humans and animals, posing a food safety risk. The detection of yeasts in food, determination of their cell number, as well as identification and typing, are therefore often tasks during the examination of certain food categories. The methods employed to achieve these objectives are diverse, encompassing both conventional culture-based techniques and more recent, genome-based studies. The objective of this study is to provide a summary article that presents the methods suitable for testing food-derived yeasts. The article will highlight the advantages, disadvantages, and potential difficulties of their applicability. Moreover, a comprehensive review of nucleic acid-based, culture-dependent and culture-independent molecular yeast identification techniques was conducted, encompassing scientific articles from the past five years (2020–2024). The search was based on the Science Direct database using the keywords “yeast and molecular identification and food”.

The spread of superbugs in dairy products can jeopardize global public health. To date, information on the incidence rates of virulent and β-lactams-resistant (BLR) Salmonella in cheeses from rural areas of Egypt has been lacking. Biochemical, serological, antibiotic susceptibility, and multiplex PCR (M-PCR) tests were performed to identify and characterize Salmonella isolates. In this study, 44 (15.71%) Salmonella isolates of eight different serotypes were recovered from 280 samples of Rumi and pasteurized Kariesh cheeses across the Nile Delta region of Egypt. The most predominant serotypes were S. Typhimurium, S. Enteritidis, and S. Infantis. The virulence genes (invA, stn, and hilA) were identified in all isolates. However, spvC was only detected in S. Typhimurium. The highest resistance was developed against Erythromycin and Clindamycin (90.91%), followed by Ceftazidime and Cephalothin (84.09%). Meropenem and colistin were the most effective antibiotics. A high proportion (79.55%) of multi-drug resistance (MDR) isolates carried narrow spectrum (NS), extended-spectrum (ES), and AmpC-BLR genes. The bla_OXA-1, bla_OXA-2, bla_TEM-1, bla_CTX-M, bla_CMY-1, and bla_CMY-2 BLR genes were positive in 37.04%, 29.63%, 25.93%, 14.81%, 37.04%, and 3.70% of isolates, respectively. In conclusion, a high prevalence of virulence and BLR genes harboring Salmonella strains in Egyptian cheeses is considered a great threat to public health.

Staphylococcus aureus (S. aureus) as a major pathogen is implicated in a wide range of foodborne and hospital-acquired infections, its methicillin resistant variants contribute to the spread of β-lactam antibiotics resistance. It is essentially important to destroy these pathogens, their resistant genes and the antibiotics in wastewaters. For this purpose reactions of reactive radicals (advanced oxidation processes), first of all hydroxyl radicals (^•OH), are suggested. Here the radiolysis of water supplied these radicals. In the experiments B.01755 oxacillin sensitive and B.02174 resitant S. aureus strains were used studying their behaviour in suspensions under the effect of irradiation in presence and absence of oxacillin. Oxacillin inactivation depended on concentration of the antibiotic used (0.042 and 1 g dm^-3), higher concentration required a higher dose. When 10⁶-10⁹ CFU cm^-3 S. aureus suspensions were irradiated with γ-radiation the bacteria were inactivated at low absorbed doses: 4 orders of magnitude decrease ocurrred in the number of culturable stains at ∼0.6 kGy dose. Both cell membrane and DNA sufferred considerable damages during irradiation. Due to the membrane damage the cells could not be stained, and the DNA content of cells in several days period was released into the solution. In DNA damage the oxacillin resistant mecA gene was also modified, it did not multiply in PCR test. These findings are important from the point of view of applying irradiation technology to stop the spread of antibiotic resistance.

Previously isolated Pseudomonas lundensis CP-P-5 had antagonistic activity against Salmonella Hartford, Yersinia enterocolitica, and Escherichia coli. In this study, determination of its antagonistic mechanism and potential field of application in food industry was aimed. Using cellophane-test and microcultures of the test strain's cell-free supernatant mixed with the pathogens, our results showed that cells of P. lundensis CP-P-5 and its concentrated cell-free supernatants were effective against the foodborne bacteria, and the supernatants contained more than one compound responsible for inhibitory activity. Searching for the antagonistic compound, NaOH, protease, and heat treatments were done to the supernatants, and proteolytic activity and siderophore production were also tested using the antagonistic strain. Our results support the potential applicability of P. lundensis CP-P-5 as a bioprotective agent against foodborne pathogens in food processing environments.