Descontaminação de carcaças de suínos em matadouro
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2021-05-25
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Os problemas de contaminação, contaminação cruzada ou recontaminação de carcaças de suíno por microrganismos deteriorativos e patogénicos ocorrem principalmente durante os processos de abate. Durante o processo de obtenção de carcaças em matadouro, é possível minimizar a contaminação por Salmonella spp. através da utilização de boas práticas higiénicas e de fabrico durante as operações de abate, no entanto, é impossível garantir a sua inativação. Deste modo, o estudo de estratégias de descontaminação de carcaças de suíno pode ser uma solução viável aumentando a probabilidade de redução ou destruição do microrganismo bem como outra microbiota presente na superfície de carcaças, melhorando as características microbiológicas do produto final – carcaça de suíno. Este estudo teve como objetivo avaliar a eficiência de dois ácidos orgânicos e do quitosano como descontaminantes em carcaças de suínos. Uma mistura de suspensões bacterianas de Salmonella Typhimurium e Salmonella Derby num primeiro ensaio, e um mix de Listeria monocytogenes ATCC e Listeria monocytogenes ambiental num segundo ensaio, foram inoculadas em amostras de courato de cerca de 25 cm2 em duas concentrações. Para a suspensão bacteriana de Salmonella spp. foram usadas as concentrações 1,42 × 105 UFC/cm2 (suspensão A) e 4,92 × 106 UFC/cm2 (suspensão B). Para o mix de Listeria monocytogenes foram usadas as concentrações de 1,74 × 105 UFC/cm2 (suspensão 1) e 6,38 × 106 UFC/cm2 (suspensão 2). As amostras foram descontaminadas por pulverização com os ácidos orgânicos e o quitosano (cada um individualmente), utilizando concentrações: 2% ou 5% de ácido láctico e ácido cítrico, 0,2% ou 0,5% para o quitosano. Foram analisados cinco tempos diferentes, 30 minutos, 6, 12, 24 e 48 horas. Nas amostras controlo, no ensaio da Salmonella spp. e para a suspensão A, houve um aumento de 1,36 log UFC/cm2 nas contagens de Salmonella spp. e para a suspensão B, verificou-se um aumento de 1,43 log UFC/cm2 . Com a aplicação dos ácidos orgânicos e do quitosano foi possível observar contagens inferiores às obtidas no controlo. O ácido lático 5% e o quitosano 0,2% e 0,5% apresentaram melhores resultados nas contagens de Salmonella spp., obtendo-se um efeito bacteriostático para ambos, e um efeito bactericida para o quitosano. No ensaio de Listeria monocytogenes, observou-se também um aumento das contagens, sendo que para o controlo na suspensão 1 obteve-se um aumento de 3,03 log UFC/cm2 , e para a suspensão 2 verificou-se um aumento de 2,19 log UFC/cm2 . Neste caso, os ácidos orgânicos e o quitosano mostraram um efeito bacteriostático, sendo que aquele que mostrou melhores resultados foi o quitosano 0,5%.
The problems of pig carcasses contamination, cross-contamination or recontamination by pathogenic and deteriorating microorganisms occur mainly during slaughter processes. During this process, it is possible to minimize contamination by Salmonella spp. by using good hygienic and processing practices, however, it is impossible to ensure their inactivation. This way, the decontamination of pig carcasses can be a viable solution, allowing the reduction or destruction of this microorganism and other types of microbiota present on the surface of the carcasses, improving the microbiological characteristics of the final product - pig carcass. This study aimed to evaluate the efficiency of two organic processes and chitosan as decontaminants in pig carcasses. A mixture of bacterial suspensions of Salmonella Typhimurium and Salmonella Derby was used in the first trial, and a mixture of Listeria monocytogenes ATCC and Listeria monocytogenes environmental was used in the second trial. They were inoculated in a rind with approximately 25 cm2 , using different concentrations. For the Salmonella spp. bacterial suspension, 1.42×105 CFU/cm2 (suspension A) and 4.92×106 CFU/cm2 (suspension B) concentrations were used. For the mix of Listeria monocytogenes were used 1.74×105 CFU/cm2 (suspension 1) and 6.38×106 CFU/cm2 (suspension 2) concentrations. The samples were decontaminated by spraying the organic products and the chitosan (each individually), using 2% or 5% concentration for lactic and citric acids and 0.2% or 0.5% for chitosan. Five different evaluation periods were used, 30 minutes, 6, 12, 24 and 48 hours. In the control samples, an increase of 1.36 log CFU/cm2 for suspension A and an increase of 1.43 log CFU/cm2 for suspension B in Salmonella spp. counts were observed. By applying the organic acids and chitosan, it was possible to observe lower counts than those obtained in the controlsamples. Lactic acid 5% and chitosan 0,2% and 0.5% showed better results in the counts of Salmonella spp., also obtaining a bacteriostatic effect. Regarding the Listeria monocytogenes trial, an increase in counts was also observed. For the control suspension 1, an increase of 3.03 log CFU/cm2 was obtained and for suspension 2, an increase of 2,19 log CFU/cm2 . In this case, organic acids and chitosan showed a bacteriostatic effect, the best results were obtained using 0.5% chitosan.
The problems of pig carcasses contamination, cross-contamination or recontamination by pathogenic and deteriorating microorganisms occur mainly during slaughter processes. During this process, it is possible to minimize contamination by Salmonella spp. by using good hygienic and processing practices, however, it is impossible to ensure their inactivation. This way, the decontamination of pig carcasses can be a viable solution, allowing the reduction or destruction of this microorganism and other types of microbiota present on the surface of the carcasses, improving the microbiological characteristics of the final product - pig carcass. This study aimed to evaluate the efficiency of two organic processes and chitosan as decontaminants in pig carcasses. A mixture of bacterial suspensions of Salmonella Typhimurium and Salmonella Derby was used in the first trial, and a mixture of Listeria monocytogenes ATCC and Listeria monocytogenes environmental was used in the second trial. They were inoculated in a rind with approximately 25 cm2 , using different concentrations. For the Salmonella spp. bacterial suspension, 1.42×105 CFU/cm2 (suspension A) and 4.92×106 CFU/cm2 (suspension B) concentrations were used. For the mix of Listeria monocytogenes were used 1.74×105 CFU/cm2 (suspension 1) and 6.38×106 CFU/cm2 (suspension 2) concentrations. The samples were decontaminated by spraying the organic products and the chitosan (each individually), using 2% or 5% concentration for lactic and citric acids and 0.2% or 0.5% for chitosan. Five different evaluation periods were used, 30 minutes, 6, 12, 24 and 48 hours. In the control samples, an increase of 1.36 log CFU/cm2 for suspension A and an increase of 1.43 log CFU/cm2 for suspension B in Salmonella spp. counts were observed. By applying the organic acids and chitosan, it was possible to observe lower counts than those obtained in the controlsamples. Lactic acid 5% and chitosan 0,2% and 0.5% showed better results in the counts of Salmonella spp., also obtaining a bacteriostatic effect. Regarding the Listeria monocytogenes trial, an increase in counts was also observed. For the control suspension 1, an increase of 3.03 log CFU/cm2 was obtained and for suspension 2, an increase of 2,19 log CFU/cm2 . In this case, organic acids and chitosan showed a bacteriostatic effect, the best results were obtained using 0.5% chitosan.
Descrição
Dissertação de mestrado em Engenharia Alimentar
Palavras-chave
descontaminação , carcaças de porco