The present study aimed to assess the antimicrobial resistance and the presence of virulence markers in 137 Listeria monocytogenes isolates obtained from meat-processing environments, beef products, and clinical cases. All isolates were subject to molecular serogrouping and their antibiotic resistance profiles were assessed against 12 antimicrobials. In addition, isolates were subjected to detection of virulence marker genes (inlA, inlC, inlJ). The isolates were classified into serogroups 4b, 4d, 4a, or 4c (46%), 1/2c or 3c (27%), 1/2a or 3a (13.9%), and 1/2b or 3b (13.1%). All tested isolates presented sensitivity to the majority of the tested antimicrobials, but most of them presented resistance or intermediate resistance to clindamycin (88.3%) and oxacillin (73.7%). Virulence markers were detected in all isolates, demanding further analysis to better characterize their pathogenic potential.

Salmonella can contaminate finished products of butcher shops, mainly through cross-contamination of utensils exposed to raw materials. To identify the main sources of contamination with this foodborne pathogen in four butcher shop environments, surface samples were obtained from employees' hands, cutting boards, knives, floor of the refrigeration room, meat grinders, and meat tenderizers (32 samples per area) and analyzed for Salmonella using the International Organization for Standardization method 6579, with modifications. Suspect isolates were identified by PCR (targeting ompC), and confirmed Salmonella isolates were subjected to pulsed-field gel electrophoresis (after treatment with restriction enzyme XbaI), analyzed for the presence of virulence genes (invA, sefA, and spvC), and screened for resistance to 12 antimicrobials. Salmonella isolates was identified only on cutting boards (five samples) from three butcher shops. Fifteen isolates were confirmed as Salmonella belonging to four pulse types (similarity of 71.1 to 100%). The invA gene was detected in 13 isolates, and the sefA was found in 8 isolates; no isolate carried spvC. All tested isolates were resistant to clindamycin and sensitive to amikacin and cefotaxine, and all isolates were resistant to at least 3 of the 12 antimicrobials tested. The results indicate the importance of cutting boards as a source of Salmonella contamination in butcher shops. The presence of multidrug-resistant Salmonella strains possessing virulence genes highlights the health risks for consumers.

The quality and safety of meat products can be estimated by assessing their contamination by hygiene indicator microorganisms and some foodborne pathogens, with Listeria monocytogenes as a major concern. To identify the main sources of microbiological contamination in the processing environment of three butcher shops, surface samples were obtained from the hands of employees, tables, knives, inside butcher displays, grinders, and meat tenderizers (24 samples per point). All samples were subjected to enumeration of hygiene indicator microorganisms and detection of L. monocytogenes, and the obtained isolates were characterized by their serogroups and virulence genes. The results demonstrated the absence of relevant differences in the levels of microbiological contamination among butcher shops; samples with counts higher than reference values indicated inefficiency in adopted hygiene procedures. A total of 87 samples were positive for Listeria spp. (60.4%): 22 from tables, 20 from grinders, 16 from knives, 13 from hands, 9 from meat tenderizers, and 7 from butcher shop displays. Thirty-one samples (21.5%) were positive for L. monocytogenes, indicating the presence of the pathogen in meat processing environments. Seventy-four L. monocytogenes isolates were identified, with 52 from serogroups 1/2c or 3c and 22 from serogroups 4b, 4d, 4a, or 4c. All 74 isolates were positive for hlyA, iap, plcA, actA, and internalins (inlA, inlB, inlC, and inlJ). The establishment of appropriate procedures to reduce microbial counts and control the spread of L. monocytogenes in the final steps of the meat production chain is of utmost importance, with obvious effects on the quality and safety of meat products for human consumption.

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Avaliou-se a qualidade de cinco leites fermentados brasileiros, coletados em pontos de vendas de Viçosa (MG), assim como a atividade antagonista in vitro de suas bactérias ácido láticas para micro-organismos indicadores desejáveis e patogênicos. Todos os lotes avaliados estavam em conformidade com a legislação brasileira quanto ao teor de gordura e contagem de bolores e leveduras. Alguns lotes evidenciaram acidez titulável (20 %) e teor de proteína (52 %) abaixo do limite permitido pela legislação nacional. Quanto à concentração de bactérias ácido láticas, 32 e 96 % dos lotes não apresentaram contagens mínimas em conformidade com os limites estabelecidos pelo MAPA e pela ANVISA, respectivamente, o que implica na necessidade de fi scalização do produto. As bactérias ácido láticas demonstraram maior antagonismo para Salmonella enterica, Escherichia coli e Staphylococcus aureus que para a bactéria ácido lática utilizada como indicadora. Alguns lotes de leites fermentados não estavam em conformidade com a legislação, ainda que as bactérias ácido láticas avaliadas tenham importância para a preservação de produtos e controle de patógenos.

O resfriamento do leite após a ordenha em todas as dimensões dos tanques de expansão deve preservar as características do leite. Portanto, o objetivo do trabalho foi verificar a temperatura do leite cru mensurada por termostato e termômetro em pontos superficiais e do fundo de 33 tanques de expansão no Vale do Rio Doce (MG). Os dados foram relacionados com a qualidade do leite e conhecimento dos produtores quanto à refrigeração do leite. A temperatura média mensurada pelo termostato do tanque de refrigeração foi inferior (p<0,05) às temperaturas médias mensuradas pelos termômetros, mas estas foram iguais (p>0,05) em pontos diferentes no interior do tanque. A contagem bacteriana do leite foi maior (p<0,05) em tanques com alta temperatura de armazenamento, o que causou desconformidade de 42,4% de amostras quanto a legislação. A falta de informação dos produtores a respeito da refrigeração correta do leite e a refrigeração inadequada de tanques comprometeram a qualidade e conformidade de 10% de amostras quanto à legislação. A manutenção e inspeção de tanques devem ser efetivadas de forma constante. PALAVRAS-CHAVE:Qualidade. Refrigeração. Legislação. Inspeção.

The present study aimed to assess the performance of alternative protocols to enumerate lactic acid bacteria (LAB) in salami. Fourteen cultures and two mixed starter cultures were plated using six protocols: 1) Petrifilm™ Aerobic Count (AC) with MRS broth and chlorophenol red (CR), incubated under aerobiosis or 2) under anaerobiosis, 3) MRS agar with CR, 4) MRS agar with bromocresol purple, 5) MRS agar at pH5.7, and 6) All Purpose Tween agar. Samples of salami were obtained and the LAB microbiota was enumerated by plating according protocols 1, 2, 3 and 5. Regression analysis showed a significant correlation between the tested protocols, based on culture counts (p<0.05). Similar results were observed for salami, and no significant differences of mean LAB counts between selected protocols (ANOVA, p>0.05). Colonies were confirmed as LAB, indicating proper selectivity of the protocols. The results showed the adequacy of Petrifilm™ AC supplemented with CR for the enumeration of LAB in salami.

ResumoThe main starter cultures used for the production of fermented meat products are microorganisms from the group of lactic acid bacteria (LAB) and Staphylococcus coagulase negative. Monitoring the populations is essential for maintaining the quality and safety of these products. However, conventional methods for enumeration of starter cultures in foods have limitations, due to poor selectivity and handling. Considering the lack of scientific data demonstrating the relevance of using Petrifilm™ AC plates associated with selective culture media for LAB enumeration in fermented meat products, the present study aimed to assess alternative protocols for the enumeration of starter culture in salami. Fourteen reference strains and two mix of starter cultures were plated on six different protocols: 1) Petrifilm™ AC added to chlorophenol red incubated in aerobiosis and 2) in anaerobiosis 3) agar MRS added to chlorophenol red 4) MRS added to bromocresol purple 5) MRS pH 5.7 and 6) agar All Purpose Tween. Then, samples of salami were obtained and their starter cultures enumerated by plating using protocols 1, 2, 3 and 5. The analysis of variance showed no significant differences between the enumeration protocols, independent of the incubation time: 24, 48 and 72 h. Generally, the counts of pure cultures of microorganisms and reference starter cultures showed no significant differences considering the different incubation times (except for AS 308 and S. xylosus in MRS at pH 5.7). The results indicated a significant 153