Salmonella enterica in cull sows and meat from cull sows

Abstract

The objective of this study was to examine the prevalence of Salmonella enterica in cull sows from farm to the abattoir. Cull sows (n = 181) were sampled over 10 weeks. Fecal samples (10 g) were collected at the farm approximately 24 h before loading and at the live hog market approx. 3 h before loading. Tissue samples (ileocecal lymph node, cecal contents, transverse colon contents, ventral thoracic lymph node, subiliac lymph node, sponge swabs of the left and right carcass section, and chopped meat) were collected at the abattoir. The percent of positive fecal samples at the farm and the live hog market were 3% (5 of 181) and 2% (3 of 181), respectively. After transport from the live hog market (10 h) and holding at the abattoir (6 h), 41% (74 of 180) of cull sows yielded S. enterica in one or more sampled tissues. Total cecal content isolation rates (33 %; 60 of 180) were significantly (P < 0.05) higher than ileocecal lymph node (7%; 12 of 181), abattoir fecal (11%; 20 of 181), and ventral thoracic/subiliac lymph node (2%; 4 of 181) isolation rates. Before a 2% lactic acid carcass wash (8 to 9 second duration), 14% (25 of 180) of carcasses were positive compared to 7% (12 of 179) after the carcass wash (P < 0.05). Two S. enterica serotypes were found at the farm and the live hog market, Derby and Infantis. At the abattoir, 12 serotypes were recovered but not previously found at the farm or the live hog market. This study demonstrates that transport and holding practices may contribute to an increased S. enterica infection prior to slaughter to levels much higher than found on farm.