Biofilms are of great concern for the meat industry because, despite the implementation of control plans, they remain important hotspots of contamination by foodborne pathogens, highlighting the need to better understand the ecology of these microecosystems. The objective of this paper was to critically survey the recent scientific literature on microbial biofilms of importance for meat safety and quality, also pointing out the most promising methods to combat them. For this, the databases PubMed, Scopus, Science Direct, Web of Science, and Google Scholar were surveyed in a 10-year time frame (but preferably papers less than 5 years old) using selected keywords relevant for the microbiology of meats, especially considering bacteria that are tolerant to cleaning and sanitization processes. The literature findings showed that massive DNA sequencing has deeply impacted the knowledge on the species that co-habit biofilms with important foodborne pathogens (Listeria monocytogenes, Salmonella, pathogenic Escherichia coli, and Staphylococcus aureus). It is likely that recalcitrant commensal and/or spoilage microbiota somehow protect the more fastidious organisms from harsh conditions, in addition to harboring antimicrobial resistance genes. Among the members of background microbiota, Pseudomonas, Acinetobacter, and Enterobacteriales have been commonly found on food contact and non-food contact surfaces in meat processing plants, in addition to less common genera, such as Psychrobacter, Enhydrobacter, Brevundimonas, and Rothia, among others. It has been hypothesized that these rare taxa may represent a primary layer in microbial biofilms, offering better conditions for the adhesion of otherwise poor biofilm formers, especially considering their tolerance to cold conditions and sanitizers. Taking into consideration these findings, it is not only important to target the foodborne pathogens per se in cleaning and disinfection plans but the use of multiple hurdles is also recommended to dismantle the recalcitrant structures of biofilms. In this sense, the last part of this manuscript presents an updated overview of the antibiofilm methods available, with an emphasis on eco-friendly approaches.

This study evaluated the sanitary hygienic quality and the presence of pathogenic microorganisms in raw meats and fresh sausages marketed in the city of Uruguaiana, Rio Grande do Sul (RS), Brazil. We analyzed 238 samples of fresh sausages, beef, pork, and chicken from 18 commercial establishments (butchers, supermarkets, and groceries). Samples were subjected to enumerate hygiene indicator microorganisms (mesophilic aerobes and enterobacteria) and detection of Salmonella spp. and Listeria monocytogenes. The mean counts of mesophilic aerobes and enterobacteria were 5.09 and 3.54 log CFU/g, respectively. Beef samples presented the highest frequency of Salmonella spp. (7.93%) and fresh sausages present the highest frequency of L. monocytogenes (19.04%). Among the analyzed samples, 43.70% did not comply with the microbiological parameters established by the Brazilian Ministry of Health. The presence of Salmonella spp. and L. monocytogenes in different samples and commercial establishments demonstrate the failures of good manufacturing practices in industrial environmental and retails points and the need to train food handlers to reduce the exposure of consumers to potential risks.

Chicken meat production is a critical component of the global protein supply, significantly influenced by rearing advancements, including the use of antimicrobial agents. However, the pervasive use of antibiotics has raised concerns regarding the occurrence of antimicrobial resistance (AMR). This study examined the prevalence and AMR profiles of Salmonella spp., Escherichia coli, and Enterococcus spp. in chicken meat from conventional and antibiotic-free (ABF) production chains. A total of 284 samples were analyzed for Salmonella spp. and E. coli, while 164 samples were tested for Enterococcus spp. From that, 143 were from conventional production chains and 141 were from ABF chains. The results indicated a 10.9% prevalence of Salmonella spp., 22.1% for E. coli, and 93.9% for Enterococcus spp. Regarding production chains, the conventional chain had 18.2% of the isolates for Salmonella spp., 20.3% for E. coli, and 91.6% for Enterococcus spp., while the ABF chain had 3.5% of the isolates for Salmonella spp., 24.1% for E. coli, and 96.3% for Enterococcus spp. In terms of AMR, 86.1% of the Salmonella spp. isolates that underwent the disk diffusion test were resistant to at least one antibiotic tested, 95.1% of E. coli, and 88.4% of Enterococcus spp. Notably, carbapenem resistance was detected in Salmonella spp., with 2.3% of isolates being resistant to imipenem, while resistance to vancomycin and linezolid was detected in Enterococcus spp., all of which are critically important antimicrobials. Comparisons between these production chains revealed significant differences in antibiotic resistance patterns in Salmonella spp. for two antibiotics, amoxicillin/clavulanic acid and nitrofurantoin, while no differences were observed in E. coli. For Enterococcus spp., resistance varied for three antibiotics: streptomycin, penicillin, and tetracycline. For all other antibiotics tested, the resistance profiles were consistent across both conventional and ABF production chains. Multidrug resistance (MDR) was observed in 90.7% of Salmonella spp. isolates, 42.9% of E. coli isolates, and 12.0% of Enterococcus spp. isolates. Statistically significant differences were noted in MDR prevalence between production chains, with conventional production systems exhibiting higher levels of MDR isolates compared to ABF systems. These findings underscore the need for targeted AMR control strategies that consider the complexity of resistance dynamics across production systems.

This study assessed the viable and culturable microbial diversity that remained on equipment surfaces after hygiene procedures in Brazilian poultry and fish slaughterhouses. Food-contact surface samples were collected using sterile swabs in poultry (n = 50) and fish (Oreochromis niloticus, n = 50) slaughterhouses. The swab samples were used to prepare culture plates to recover viable and culturable cells. The grown plates were washed, and the total DNA of the cell suspension was extracted with a commercial kit. Sequencing of the total DNA extracted from cultures was targeted at the V3 and V4 regions of the 16S rRNA. DNA reads were analyzed by QIIME2 software, with results expressed in relative frequency (%RF). Alpha and beta diversity indexes were analyzed considering the spots of sample collection, type of industry, surfaces (smooth or modular), and materials (polypropylene, stainless steel, or polyurethane). The results showed that in the poultry slaughterhouse, the most abundant genera were Acinetobacter (27.4%), Staphylococcus (7.7%), and Pseudomonas (5.3%), while for the fish slaughterhouse, there was a higher abundance of Staphylococcus (27.7%), Acinetobacter (17.2%), and Bacillus (12.5%). Surface characteristics influenced the microbial diversity, with Acinetobacter spp. dominating modular surfaces and Staphylococcus spp. prevailing on smooth surfaces. The results obtained indicate there is an important resident microbiota that persists even after hygiene processes, and surface-specific cleaning strategies should be developed.

The aim of this study was to investigate the impact of Good Manufacturing Practices (GMP) on the identification and prevention of bacteria that could pose a risk to patient meals. The study used two GMP checklists and microbiological sampling of bacteria, performed six months apart, to assess the facility’s ability to reduce bacterial counts. The results showed hygiene deficiencies in all areas of the hospital. However, there was a significant improvement in GMP compliance following the implementation of an action plan (p = 0.0234). Before the intervention, 55.55% of the criteria were compliant and after the intervention, 69.63% were compliant. Surfaces involved in raw material handling were identified as the most critical in terms of contamination, with high levels of aerobic mesophilic count, Enterobacteriaceae, and Listeria monocytogenes. The intervention significantly reduced the number of bacteria on these surfaces (p < 0.05). Before, the aerobic mesophilic ranged from 0.00 to 6.34 log CFU/cm², and after, from 0.00 to 4.31 log CFU/cm². Additional testing of incoming materials, food, and hands showed no significant risk. The study highlighted the importance of good hand hygiene, which improved after extensive staff training. The GMP guideline and microbiological characterization of the production areas in the hospital kitchens were essential for understanding and acting on bacterial contamination.