Quantity and distribution of Salmonella recovered from three swine lairage pens.

Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, Iowa 50010, USA.
Journal of food protection (Impact Factor: 1.85). 08/2006; 69(7):1717-9.
Source: PubMed


The quantity of Salmonella recoverable from three lairage pens in a swine abattoir was determined. Using dry four-ply cotton gauze pads measuring 10 by 10 cm, 100 fecal slurry samples were collected from each of the three pens. Salmonella recovery was expressed as the log CFU per milliliter of sample. Mean values were 2.5 log CFU/ml in pen A, 2.7 log CFU/ ml in pen B, and 0.89 log CFU/ml in pen C. Median values were 2.6 log CFU/ml in pen A, 2.0 log CFU/ml in pen B, and below the detectable limit in pen C. In pen C, Salmonella was not recoverable from a high number of samples. Pen B results suggested spatial dependency, i.e., samples close together were more similar than samples farther apart. These results indicate that Salmonella concentrations vary within and between lairage pens. Because of the limited number of pens assessed, it was not possible to identify factors that were associated with the observed variation in Salmonella concentrations within and between pens. However, this variation suggests that numeroussamples are required to adequately describe the concentration of Salmonella in a lairage pen.

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    ABSTRACT: Abstract Quantification of Salmonella in asymptomatic pigs can be used to institute control measures and to assess risk of carcass contamination during slaughter. The objective of this study was to quantify the fecal concentration of Salmonella in naturally infected pigs. Individual fecal samples (positive [n=443], negative [n=1225] determined by microbiological culture) were submitted for direct quantitative real-time polymerase chain reaction (q-PCR). Direct q-PCR categorized 99.6% (1220/1225) of culture negative samples as negative. For culture positive samples, 15.4% (68/443) were detected by q-PCR, but only 3.4% (15/443) were within the direct q-PCR quantifiable range (≥10(3) colony-forming units [CFU]/g of feces). Of these latter samples, the concentration range was 1.06×10(3) to 1.73×10(6) CFU/g feces. Of the 15 samples with high Salmonella concentrations, seven were collected from one pig and three samples were collected from its penmates. Direct q-PCR may be an alternative to traditional culture-dependent methods for detection of pigs with high fecal concentrations of Salmonella, but not for detection of pigs shedding low concentrations of Salmonella, which represented the majority of pigs in this study. When high shedding was detected it was clustered within a single pig and its penmates. These data contribute to quantitative risk assessments of the association between concentrations of Salmonella shed by pigs during the finishing phase and risk of carcass contamination at slaughter.
    Foodborne Pathogens and Disease 08/2013; 10(11). DOI:10.1089/fpd.2013.1547 · 1.91 Impact Factor


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