Introduction: Salmonella is a major cause of foodborne illness throughout the world. The use of quantitative techniques is important for assessing the risk and determining the capacity of each step of the slaughtering process to decrease or increase bacterial contamination. We aimed to detect and to quantify the presence of Salmonella in Brazilian processing plants by real-time quantitative polymerase chain reaction (qPCR). Methodology: A total of 139 poultry slaughterhouses samples were collected in order to detect to and quantify Salmonella by qPCR. Results: Almost all collection points (3/18), except water from pre-chiller tank, carcasses after pre-chiller, and carcasses frozen at -12ºC for 60 days, and 49% (68/139) of samples were positive for Salmonella. Quantification means varied equally among all of the tested sources, and we could not establish any pattern of variation. A large proportion (52.6%) of cloacal swabs was Salmonella-positive. Also, contamination in transport cages was increased after the cleaning process, indicating that the process was ineffective. The overall prevalence in samples obtained during the slaughtering process was 48.9%, and on the whole rinsed carcasses, this proportion was 50%. The detection of Salmonella in frozen carcasses, even after long periods of storage, indicates that the carcasses are a potential source of infection for consumers. Conclusions: We found that contamination levels remain similar throughout the slaughtering. qPCR proved to be an efficient method for the detection of Salmonella.

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Background: Listeria monocytogenes is a pathogenic bacterium that can contaminate food and cause public health problems due its ability to form biofilms and resistance to sanitizers, it is responsible for sanitary and economic losses in food producing establishments. The difficulties in controlling biofilms and increasing resistance to traditional antibacterial agents is motivating studies of alternative potential biological agents for the control of pathogenic biofilms, among which lactic acid bacteria (LABs) are included. The objective of this work was to evaluate the activity of LABs against Listeria monocytogenes biofilm formation on polystyrene plates, a surface commonly used in the food industry.Materials, Methods & Results: Lyophilized commercial strains of Bifidobacterium animalis, Lactobacillus fermentum, Lactobacillus plantarum, Lactobacillus salivaris and Lactobacillus acidophilus were used. The strain of Listeria monocytogenes (L4) was isolated from polystyrene mats from a poultry slaughterhouse cutting room and demonstrated the ability to attach to microplates and resistance to sanitizers (sodium hypochlorite and hydrogen peroxide) at all times, temperatures and tested surfaces. The antimicrobial activity of LABs was evaluated by the agar diffusion method. The LABs that presented action on Listeria monocytogenes were selected for the inhibition and/or removal of biofilms in microplates, and all experiments were carried out in triplicate. Only Bifidobacterium animalis and Lactobacillus plantarum demonstrated action against Listeria. monocytogenes in the agar diffusion assays and were selected for inhibition and competition assays. Furthermore, competition of LABs against Listeria monocytogenes adhesion was evaluated. There was no significant difference between LABs and Listeria monocytogenes, alone or in combination, at temperatures of 30ºC and 37ºC in the Listeria monocytogenes inhibition assays on polystyrene surface. The lactic acid bacteria evaluated did not demonstrate inhibition of Listeria monocytogenes adhesin testes with optical density visualization, however, it was possible to identify a reduction in Listeria monocytogenes counts with the application of Bifidobacterium animals and Lactobacillus plantarum in the testes of competition against biofilm formation. In competition tests Bifidobacterium animalis and Lactobacillus plantarum have an injunction in Listeria monocytogenes, indicating that these lactic acid bacteria can retard Listeria biofilm formation on polystyrene surfaces and thus help control the pathogen in the food industry.Discussion: A potential mechanism to control biofilm adhesion and formation of pathogens for nutrients and fixation on surfaces, multiplication factors and surfaces are a challenge in controlling biofilms of pathogenic microorganisms, alternative measures to traditional methods for inactivating pathogens and biofilm formers bacteria are necessary. In this sense, lactic acid bacteria generate high levels of bacteriocin and are effective in inhibiting the biofilm of pathogenic bacteria, however, our study did not reveal this. We verified that Bifidobacterium animalis and Lactobacillus plantarum have an inhibitory action on Listeria monocytogenes, indicating that these lactic acid bacteria can be used to delay the formation of biofilms by Listeria on polystyrene surfaces, helping to control this pathogen in food industry.Keywords: control of biofilm, pathogenic bacteria, food industry, polystyrene surface, FTDs.

Antimicrobial resistance is a serious public health problem and Salmonella spp. is highly resistant to antimicrobial agents. Biofilms are important in the food industry due to their formation on products, utensils, and surfaces and the difficulty in their removal. The objective of this study was to assess extended spectrum betalactamase (ESBL) production, antimicrobial resistance, and biofilm production of Salmonella isolated from poultry slaughterhouses. Antimicrobial susceptibility was assessed by the disk diffusion assay and ESBL by double diffusion disk assay using the beta-lactamase inhibitor (amoxicillin+clavulanate). The antimicrobials tested were: ampicillin, amoxicillin+clavulanate, aztreonam, ceftazidime, cefotaxime, chloramphenicol, gentamicin, enrofloxacin, sulfonamide, and tetracycline. Serovars Infantis, Panamá, and Tennessee were found to produce ESBL. All serovars were sensitive to tetracycline, and S. Brandenburg was sensitive to all drugs tested. Serovars Panamá, Anatum, Infantis, and Schwarzengrund were moderate biofilm producers at 3 ºC and 9 ºC±1 ºC, respectively, showing possible adaptation of these serovars to these temperatures. Antimicrobials should be used with caution because of the levels of resistance observed and because of ESBL production, and hygiene and sanitary measures should be enhanced to minimize the adhesion of biofilmforming Salmonella serovars at refrigeration temperatures.