RESUMO
Salmonella is traditionally identified by conventional microbiological tests, but the enumeration of this bacterium is not used on a routine basis. Methods such as the most probable number (MPN), which utilize an array of multiple tubes, are time-consuming and expensive, whereas miniaturized most probable number (mMPN) methods, which use microplates, can be adapted for the enumeration of bacteria, saving up time and materials. The aim of the present paper is to assess two mMPN methods for the enumeration of Salmonella sp in artificially-contaminated chicken meat samples. Microplates containing 24 wells (method A) and 96 wells (method B), both with peptone water as pre-enrichment medium and modified semi-solid Rappaport-Vassiliadis (MSRV) as selective enrichment medium, were used. The meat matrix consisted of 25g of autoclaved ground chicken breast contaminated with dilutions of up to 10(6) of Salmonella Typhimurium (ST) and Escherichia coli (EC). In method A, the dilution 10-5 of Salmonella Typhimurium corresponded to >57 MPN/mL and the dilution 10-6 was equal to 30 MPN/mL. There was a correlation between the counts used for the artificial contamination of the samples and those recovered by mMPN, indicating that the method A was sensitive for the enumeration of different levels of contamination of the meat matrix. In method B, there was no correlation between the inoculated dilutions and the mMPN results.
RESUMO
Salmonella is traditionally identified by conventional microbiological tests, but the enumeration of this bacterium is not used on a routine basis. Methods such as the most probable number (MPN), which utilize an array of multiple tubes, are time-consuming and expensive, whereas miniaturized most probable number (mMPN) methods, which use microplates, can be adapted for the enumeration of bacteria, saving up time and materials. The aim of the present paper is to assess two mMPN methods for the enumeration of Salmonella sp in artificially-contaminated chicken meat samples. Microplates containing 24 wells (method A) and 96 wells (method B), both with peptone water as pre-enrichment medium and modified semi-solid Rappaport-Vassiliadis (MSRV) as selective enrichment medium, were used. The meat matrix consisted of 25g of autoclaved ground chicken breast contaminated with dilutions of up to 10(6) of Salmonella Typhimurium (ST) and Escherichia coli (EC). In method A, the dilution 10-5 of Salmonella Typhimurium corresponded to >57 MPN/mL and the dilution 10-6 was equal to 30 MPN/mL. There was a correlation between the counts used for the artificial contamination of the samples and those recovered by mMPN, indicating that the method A was sensitive for the enumeration of different levels of contamination of the meat matrix. In method B, there was no correlation between the inoculated dilutions and the mMPN results.
RESUMO
Bacteria of the genus Salmonella are part of the normal flora of poultry, and its occurrence in poultry products varies with the production management methods and slaughter technology, representing risks to the consumer and difficulties in exports. S. Heidelberg appears to be more invasive and to cause more severe disease than other non-typhoidal serovars. The objective of the present study was to search for Salmonella at different points of the slaughterhouse and to report on the isolation of S. Heidelberg in a slaughterhouse under federal inspection. S. Heidelberg was isolated in poultry soon after feathering-out and in the chiller water, indicating that, although it was not isolated at another sampled points, the bacteria was present in the environment and could contaminate carcasses ready for consumption, with an impact on public health. This concern is underscored by the fact that S. Heidelberg is a proven causative agent of foodborne infections.
Bactérias do gênero Salmonella fazem parte da flora normal das aves e sua ocorrência em produtos avícolas varia com o manejo na criação e tecnologia de abate, representando riscos para o consumidor final e dificuldades nas exportações. A S. Heidelberg parece ser mais invasiva e causar doenças com maior gravidade que outros sorovares paratíficos. Este trabalho teve por objetivos pesquisar Salmonella em diferentes pontos da tecnologia de abate de frangos e relatar o isolamento de S. Heidelberg em um abatedouro sob inspeção federal. S. Heidelberg foi isolada em frangos logo após a depenagem e na água do chiller indicando que, embora não tenha sido realizado o isolamento em outros pontos amostrados, a bactéria estava presente no ambiente e poderia contaminar carcaças prontas para consumo, com reflexos na saúde pública. O isolamento de S. Heidelberg reforça esta preocupação uma vez que este sorovar tem se destacado como causador de doenças transmitidas por alimentos.
RESUMO
Bacteria of the genus Salmonella are part of the normal flora of poultry, and its occurrence in poultry products varies with the production management methods and slaughter technology, representing risks to the consumer and difficulties in exports. S. Heidelberg appears to be more invasive and to cause more severe disease than other non-typhoidal serovars. The objective of the present study was to search for Salmonella at different points of the slaughterhouse and to report on the isolation of S. Heidelberg in a slaughterhouse under federal inspection. S. Heidelberg was isolated in poultry soon after feathering-out and in the chiller water, indicating that, although it was not isolated at another sampled points, the bacteria was present in the environment and could contaminate carcasses ready for consumption, with an impact on public health. This concern is underscored by the fact that S. Heidelberg is a proven causative agent of foodborne infections.
Bactérias do gênero Salmonella fazem parte da flora normal das aves e sua ocorrência em produtos avícolas varia com o manejo na criação e tecnologia de abate, representando riscos para o consumidor final e dificuldades nas exportações. A S. Heidelberg parece ser mais invasiva e causar doenças com maior gravidade que outros sorovares paratíficos. Este trabalho teve por objetivos pesquisar Salmonella em diferentes pontos da tecnologia de abate de frangos e relatar o isolamento de S. Heidelberg em um abatedouro sob inspeção federal. S. Heidelberg foi isolada em frangos logo após a depenagem e na água do chiller indicando que, embora não tenha sido realizado o isolamento em outros pontos amostrados, a bactéria estava presente no ambiente e poderia contaminar carcaças prontas para consumo, com reflexos na saúde pública. O isolamento de S. Heidelberg reforça esta preocupação uma vez que este sorovar tem se destacado como causador de doenças transmitidas por alimentos.