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Veterinary drugs are used in dairy cattle management mainly for therapy and prophylaxis of diseases, which chemicals may leave residues in milk. Human exposure and the unintentional consumption of residues of drugs can lead to side effects and development of resistant bacteria, representing a considerable concern to consumer health. This paper presents the occurrence of residues of veterinary drugs in milk from 2009 to 2011 in Brazil, monitored by the Official Program for Analysis of Residues of Veterinary Drugs in Foods of Animal Origin. A total of 961 samples were collected in the retail and evaluated for the main β-lactams, tetracyclines, amphenicol, aminoglycosides, quinolones, sulfonamides and avermectins. Residues of veterinary drugs did not exceed maximum residue limit (MRL); although, there is a considerable use of critically/highly important antimicrobials and avermectins in dairy cows, especially quinolones and tetracyclines. Doxycycline (9%) and abamectin (1.6%) were detected, even though these substances are not intended to be used in milk producing animals for human consumption. Norfloxacin (15%) was observed; although, there are no MRL established, consequently, no residue level should have been detected. No residues of streptomycin, chloramphenicol and β-lactams were confirmed. Milk in Brazil contains low levels of veterinary drugs so that toxicological risk regarding milk consumption could not be considered as a public health concern. However, due to the nature of the samples, which correspond to milk from several farms, it could occur a dilution effect. The absence of MRL established for norfloxacin prevents suitable interpretation of the findings and makes tough the control of these chemical residues in food. Detection of some antimicrobials and avermectins may be linked to extra-label use or noncompliance withdrawal periods suggesting that good veterinary practices are not being followed, since residues of unauthorized drugs have been detected.

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ABSTRACT:The present study was conducted to verify the occurrence of Listeria spp. in 50 samples of beef carpaccio sold in bars and restaurants; and to evaluate the resistance profile to antimicrobial agents used in the routine treatment of infections. It was found that 20% of samples from restaurants and 35% from bars were contaminated with Listeria spp. Among the species, L. welshimeri was most frequently isolated (81.82%), followed by L. grayi, (13.66%) and L. monocytogenes (4.55%). The Oxford agar plating medium was the most efficient. The resistant behavior occurred to all antimicrobial agents tested, except tetracycline, to which 95.5% of the strains were sensitive. Multidrug resistance was observed in 68.75% of the strains analyzed. Thus, it is concluded that the consumption of beef carpaccio represents a potential risk, and a serious public health problem, especially due to the confirmation of pathogenic strains that are resistant to major antimicrobial agents used in the treatment of listeriosis. KEYWORDS: antibiotics; bars; hygiene; Listeria monocytogenes;restaurants; food security. RESUMO:O presente estudo foi conduzido com o objetivo de verificar a ocorrência de Listeria spp. em 50 amostras de carpaccio de carne bovina comercializados em bares e restaurantes do município de Niterói, Rio de Janeiro, e avaliar o perfil de resistência dos isolados aos agentes antimicrobianos utilizados no tratamento de infecções. Constataram-se que 20% das amostras obtidas de restaurantes e 35% de bares estavam contaminadas com Listeria spp. Dentre as espécies, L. welshimeri foi isolada com maior frequência (81,82%), seguida de L. grayi, (13,66%) e L. monocytogenes (4,55%), sendo o ágar Oxford o meio de plaqueamento mais eficiente para isolamento. Foi verificada a ocorrência de resistência dos isolados frente a todos os agentes antimicrobianos testados, exceto à tetraciclina, diante da qual 95,5% dos isolados apresentaram sensibilidade. A multirresistência foi verificada em 68,75% das estirpes analisadas. Desta forma, concluiu-se que o consumo de carpaccio de carne bovina representa risco potencial, constituindo um grave problema de saúde coletiva, especialmente devido à confirmação de estirpes patogênicas e resistentes aos principais agentes antimicrobianos utilizados no tratamento de listeriose.