Listeria monocytogenes is a particularly foodborne pathogen associated with listeriosis, which can be disseminated in food and food processing environments. This study aimed to determine the serotypes and characteristics of virulence factors and antibiotic resistance among 40 L. monocytogenes strains isolated from food (n = 27) purchased in Olsztyn (Warmia and Mazury region, Poland) and food processing environments in Poland (n = 13). Isolates were assigned to serotypes 1/2a, 1/2c, 3a, and 3c using polymerase chain reaction (PCR). The results showed that serotype 1/2a (66.7%) was the most prevalent among strains from food, and serotype 1/2c (53.8%) among strains from the food processing environments. Five different virulence factors (hlyA, prfA, inlB, luxS, sigB) were detected in all isolates from the food processing environments using PCR. The hlyA (100.0%), prfA (100.0%), and inlB (96.3%) were the most prevalent in food strains. Seven (25.9%) of the strains of food and ten (76.9%) strains from the food processing environments showed the ability to form biofilm. The tested isolates were subjected to antibiotic susceptibility testing against 12 antibiotics used in the mitigation of listeriosis, using the disk diffusion method. The most frequent were intermediate resistance and resistance to clindamycin. Twelve (92.3%) strains from the food processing environments, and twenty-three (85.2%) from food were non-susceptible to clindamycin. Generally, antibacterial resistance determinants (Lde, aadB, aac(3)-IIa(aacC2)^a, penA, mefA, lnuA, lnuB, sulI, sulII) were detected in sixteen (59.0%) strains from food and four (30.8%) from the food processing environments, by PCR. The most frequent were the mefA-lnuA (n = 7; 20.0%) and lnuA (n = 6; 17.1%) genotypes. From this research, we can conclude that virulent and antimicrobial-resistant strains of L. monocytogenes are present in food and the food processing environment in Poland, which may pose a potential health risk to consumers. Monitoring for the control of virulent and antimicrobial-resistant L. monocytogenes strains in the food system can contribute to effective planning and prevention of their spread.

Although coagulase-positive staphylococci are considered to be the main factor responsible for food poisoning, an increasing role for the coagulase-negative staphylococci in the production of enterotoxins has been observed in recent years. This study was conducted to assess the occurrence of genes responsible for the production of staphylococcal enterotoxins (SE), enterotoxin-like toxins (SEI) and toxic shock syndrome toxin-1 (TSST-1) in coagulase-negative staphylococci (CoNS) isolated from ready-to-eat food from bars and restaurants. One hundred and eighteen CoNS strains were tested using polymerase chain reaction (PCR) to five superantigenic toxin genes, including five different types of classical enterotoxins (sea, seb, sec, sed and see) and the toxic shock syndrome toxin-1 (tsst-1) as well as to supertoxin-like genes. PCR-positive isolates were then tested using immunoenzymatic methods (SET-RPLA, Vidas SET 2) for toxin expression. Out of 118 CoNS strains, the presence of staphylococcal enterotoxins was confirmed in 72% of them. The most frequently found enterotoxin-like genotype was ser, selu. Two of the tested strains had up to ten different enterotoxin genes in the genome at the same time. Although no production of enterotoxins was detected in the CoNS, which means that their possible role in the epidemiology of food-borne diseases is minimal, the data demonstrated that the toxigenic capacity of the CoNS should not be ignored, and that this group of microorganisms should be continuously monitored in food.

High-pressure processing (HPP) is currently one of the leading methods of non-thermal food preservation as an alternative to traditional methods based on thermal processing. The application of HPP involves the simultaneous action of a combination of several factors—pressure values (100–600 MPa), time of operation (a few–several minutes), and temperature of operation (room temperature or lower)—using a liquid medium responsible for pressure transfer. The combination of these three factors results in the inactivation of microorganisms, thus extending food shelf life and improving the food’s microbiological safety. HPP can provide high value for the sensory and quality characteristics of products and reduce the population of pathogenic microorganisms such as L. monocytogenes to the required safety level. Nevertheless, the technology is not without impact on the cellular response of pathogens. L. monocytogenes cells surviving the HPP treatment may have multiple damages, which may impact the activation of mechanisms involved in the repair of cellular damage, increased virulence, or antibiotic resistance, as well as an increased expression of genes encoding pathogenicity and antibiotic resistance. This review has demonstrated that HPP is a technology that can reduce L. monocytogenes cells to below detection levels, thus indicating the potential to provide the desired level of safety. However, problems have been noted related to the possibilities of cell recovery during storage and changes in virulence and antibiotic resistance due to the activation of gene expression mechanisms, and the lack of a sufficient number of studies explaining these changes has been reported.

Postbiotics represent a promising strategy for reconciling increasing consumer demand for clean-label foods with the need to maintain high microbiological safety standards. The present review analyzed the applications of postbiotics in meat products, other food matrices and bioactive packaging, with particular emphasis on their production methods, compositional analysis and antimicrobial properties. Available evidence indicates that postbiotics offer important technological advantages over live probiotics, including enhanced stability during processing and storage and the absence of viable cells, which facilitates their integration into established food quality and safety control systems. The reviewed studies show that postbiotics produced mainly via fermentation with selected lactic acid bacteria and subsequently stabilized, most often by freeze-drying, exhibit pronounced antimicrobial activity in diverse food matrices, particularly meat and dairy products. Their ability to inhibit the growth of major foodborne pathogens, such as Listeria monocytogenes, Staphylococcus aureus, Escherichia coli, and Salmonella spp., highlights their potential as effective biopreservatives contributing to shelf-life extension and improved microbiological safety. From an industrial perspective, postbiotics can be implemented within the framework of hurdle technology and incorporated into active packaging systems and edible coatings. The wider use of postbiotics in industry remains limited by regulatory uncertainty and methodological diversity. Key challenges include inconsistent taxonomic/strain reporting, divergent methods of inactivation and final processing (which alter bioactive profiles), lack of standardized composition and potency testing, and limited food matrix validation and toxicological data. To eliminate these gaps, regulatory definitions and labelling should be harmonized, and guidelines for production and reporting (strain identity, inactivation parameters, preservation method), and targeted safety and shelf-life testing are recommended. These steps are necessary to translate the documented antibacterial and antioxidant properties of postbiotics into industrial applications.

The prevalence of antimicrobial-resistant bacteria in meat and meat products is a significant public health challenge, largely driven by the excessive and inappropriate use of antimicrobials in animal husbandry. In Poland, a key meat producer in Europe, antibiotic-resistant pathogens such as Campylobacter spp., Staphylococcus spp., Enterococcus spp., Listeria monocytogenes, and Enterobacterales have been detected in meat, posing serious risks to consumers. This review examines the use of antimicrobial agents in meat production and the resulting antimicrobial resistance (AMR) in microorganisms isolated from meat products in Poland. The mechanisms of AMR, genetic factors, and prevalence in Poland are presented. It highlights key factors contributing to AMR, such as antibiotic misuse in livestock farming, and discusses the legal regulations governing veterinary drug residues in food. This review emphasizes the importance of monitoring and enforcement to safeguard public health and calls for further research on AMR in the meat industry. Antimicrobial resistance in meat and meat products in Poland is a huge challenge, requiring stricter antibiotic controls in animal husbandry and improved surveillance systems. Additionally, the impact of husbandry practices on the environment and food requires further research. Future efforts should focus on nationwide monitoring, alternative strategies to reduce antibiotic use, and stronger enforcement to combat antimicrobial resistance and protect public health.