Ocorrência de Salmonella spp. e Enterobacteriaceae em carcaças e pele de suínos abatidos em matadouro
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2016-07-08
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Salmonella spp. é dos principais agentes patogénicos que causam toxinfeções alimentares. Em Portugal, entre 2009 e 2013, observou-se que 12% das toxinfeções alimentares foram causadas por este agente, dos quais S. Enteritidis e S. Typhimurium foram os serótipos mais identificados.
Logo após à carne de aves, a carne de suíno surge como o principal veículo de transmissão, que origina salmonelose.
O principal propósito deste estudo foi verificar a ocorrência de Salmonella spp. e de Enterobacteriaceae em carcaças e em pele de suíno abatidos em matadouro e avaliar a influência de alguns fatores de risco na sua ocorrência: o tempo de permanência na abegoaria, o momento de abate (início/fim) e a sujidade fecal visível na pele do suíno antes do abate.
As amostras foram recolhidas em duas etapas diferentes da linha de abate: após a sangria efetuou-se uma zaragatoa com esponja na pele do suíno e, antes da refrigeração efetuou-se uma zaragatoa com esponja na face externa e interna da respetiva carcaça.
Neste estudo verificou-se que no total das amostras analisadas (56/360), 15,6% revelaram a presença de Salmonella spp., das quais 29,2% (35/120) foram isoladas da pele do suíno, 13,3% na face interna da carcaça (16/120) e 4,2% na face externa (5/120). Relativamente ao nível de Enterobacteriaceae onde? verificamos uma média de 1,491 ± 1,559 (log10 ufc/cm2) valores. O teste de t-student revelou existir uma diferença significativa entre este parâmetro e a presença de Salmonella spp. na pele do suíno (p-value = 0,030) e na face interna da carcaça (p-value = 0,0015).
Após a análise estatística dos dados, verificou-se que os suínos com um maior tempo de permanência na abegoaria revelaram um maior nível de Enterobacteriaceae na sua pele e na face externa das carcaças, sendo esta diferença altamente significativa (p-value < 0,001).
Ainda, os resultados estatísticos não revelam diferenças significativas no isolamento da Salmonella spp. na pele do suíno com o tempo de permanência na abegoaria (p-value > 0,05), contudo os suínos sem Salmonella spp. tiveram em média um tempo de permanência na abegoaria inferior aos dos suínos que evidenciam Salmonella spp.
Também se constatou, que apesar das diferenças não terem sido estatisticamente significativas, o isolamento de Salmonella spp. na superfície da pele dos suínos foi superior nos animais abatidos no início comparativamente aos animais abatidos na fase final. O nível
de Enterobacteriaceae na pele do suíno também revelou ser maior nos suínos abatidos no início (p-value < 0,05).
Finalmente, o nível visual de sujidade da pele do suíno não revelou ser um bom indicador de presença de Salmonella spp. (p-value = 0,19) e do nível de Enterobacteriaceae (p-value > 0,05) na pele do suíno, não devendo ser considerado como um indicador de contaminação por estas bactérias.
Salmonella spp. is one of the major pathogens which cause food poisoning. In Portugal, between 2009 and 2013, it was verified that 12% of food poisoning cases were caused by Salmonella spp., with S. Enteritidis and S. Typhimurium identified as the most common serotypes. After the poultry meat, pork meat emerges as the main vehicle of transmission that originates salmonellosis. The main purpose of this study was to verify the occurrence of Salmonella spp. and Enterobacteriaceae on carcasses and skin of pigs slaughtered in the slaughterhouse, and to evaluate the influence of some risk factors in its occurrence: the time spent in the lairage, the moment of the slaughter (begin / end) and visible fecal contamination on the skin of the pig before slaughter. Samples were collected at two different stages of the slaughter line: a sponge swab was used to collect a sample from the surface of the pig's skin after the bleeding process, and before the refrigeration process, another sponge swab was also used to collect a sample from the outer and inner skin layer of the respective carcass. In this study it was verified that in the total number of analyzed samples (56/360), 15,6% revealed the presence of Salmonella spp., from which 29,2% (35/120) were isolated from the pig’s skin, 13,3 % in the inner side of the carcass (16/120) and 4,2% on the outer layer (5/120). Concerning the level of Enterobacteriaceae, it was observed an average of 1,491 ± 1,559 (log10 ufc/cm2) values. The t-student test revealed a significant difference between this parameter and the presence of Salmonella spp. on the pig's skin (p-value = 0.030) and (p-value = 0.0015) inside the carcass. After statistical analysis, it was found that pigs which spent more time in the lairage revealed a higher level of Enterobacteriaceae on their skin and external carcass, this being a highly significant difference (p-value < 0.001). Nevertheless, the statistical results don't reveal any significant differences in the isolation of the Salmonella spp. on a live pig's skin, during the time spent in the lairage (p-value > 0.05). However, the pigs without Salmonella spp. had on average a lower time spent in the lairage than the pigs with Salmonella spp. It was also proved that, although the differences were not statistically significant, the isolation of Salmonella spp. on the surface of the pigs’ skin was higher in animals slaughtered at the beginning, compared to animals slaughtered in the final phase. The level of Enterobacteriaceae in pigs’ skin also shown to be higher in pigs slaughtered in the beginning (p-value <0.05). Finally, the visible level of faecal contamination from the pigs’ skin wasn't found to be a good indicator of the presence of Salmonella spp. (p-value = 0.19) and the level of Enterobacteriaceae (p-value > 0.05) on the pig’s skin, and should not be taken as an indicator of infection by these bacteria.
Salmonella spp. is one of the major pathogens which cause food poisoning. In Portugal, between 2009 and 2013, it was verified that 12% of food poisoning cases were caused by Salmonella spp., with S. Enteritidis and S. Typhimurium identified as the most common serotypes. After the poultry meat, pork meat emerges as the main vehicle of transmission that originates salmonellosis. The main purpose of this study was to verify the occurrence of Salmonella spp. and Enterobacteriaceae on carcasses and skin of pigs slaughtered in the slaughterhouse, and to evaluate the influence of some risk factors in its occurrence: the time spent in the lairage, the moment of the slaughter (begin / end) and visible fecal contamination on the skin of the pig before slaughter. Samples were collected at two different stages of the slaughter line: a sponge swab was used to collect a sample from the surface of the pig's skin after the bleeding process, and before the refrigeration process, another sponge swab was also used to collect a sample from the outer and inner skin layer of the respective carcass. In this study it was verified that in the total number of analyzed samples (56/360), 15,6% revealed the presence of Salmonella spp., from which 29,2% (35/120) were isolated from the pig’s skin, 13,3 % in the inner side of the carcass (16/120) and 4,2% on the outer layer (5/120). Concerning the level of Enterobacteriaceae, it was observed an average of 1,491 ± 1,559 (log10 ufc/cm2) values. The t-student test revealed a significant difference between this parameter and the presence of Salmonella spp. on the pig's skin (p-value = 0.030) and (p-value = 0.0015) inside the carcass. After statistical analysis, it was found that pigs which spent more time in the lairage revealed a higher level of Enterobacteriaceae on their skin and external carcass, this being a highly significant difference (p-value < 0.001). Nevertheless, the statistical results don't reveal any significant differences in the isolation of the Salmonella spp. on a live pig's skin, during the time spent in the lairage (p-value > 0.05). However, the pigs without Salmonella spp. had on average a lower time spent in the lairage than the pigs with Salmonella spp. It was also proved that, although the differences were not statistically significant, the isolation of Salmonella spp. on the surface of the pigs’ skin was higher in animals slaughtered at the beginning, compared to animals slaughtered in the final phase. The level of Enterobacteriaceae in pigs’ skin also shown to be higher in pigs slaughtered in the beginning (p-value <0.05). Finally, the visible level of faecal contamination from the pigs’ skin wasn't found to be a good indicator of the presence of Salmonella spp. (p-value = 0.19) and the level of Enterobacteriaceae (p-value > 0.05) on the pig’s skin, and should not be taken as an indicator of infection by these bacteria.
Descrição
Dissertação de Mestrado em Segurança Alimentar
Palavras-chave
Salmonella , Enterobacteriaceae , Suíno , Pele , Carcaça , Contaminação