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ARS Home » Midwest Area » Ames, Iowa » National Animal Disease Center » Food Safety and Enteric Pathogens Research » Research » Publications at this Location » Publication #115819
Title: THE EFFECT OF LAIRAGE ON SALMONELLA ISOLATION FROM MARKET SWINE

Author
item HURD, HOWARD
item MCKEAN, JAMES - IOWA STATE UNIVERSITY
item WESLEY, IRENE
item KARRIKER, LOCKE - SEABOARD FARMS HEALTH

Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/10/2001
Publication Date: N/A
Citation: N/A

Interpretive Summary: This study suggests that market swine become infected with Salmonella spp., after leaving the pig farm, possibly while in the packing plant holding pens. This field study utilized 300 market swine from a single pork production facility. Thirty head were tested at the production site in each of the 10 sampling periods. Half were moved to a clean and disinfected holding facility for approximately 18 hours before both groups were transported to a commercial abattoir. The additional effects of 18 hours holding, mixing of groups, and fasting did not increase Salmonella spp. isolation rates when the holding was in clean, disinfected facilities. After slaughter, various intestinal and food safety relevant samples were cultured for the presence of Salmonella spp. Predominant serotypes found after harvest varied weekly through the 10 sample periods of this study. This study will benefit the producers, practitioners, and the packing plants.

Technical Abstract: To evaluate the effect of lairage (holding > 12 hours during transport to slaughter) in clean facilities on Salmonella isolation from market swine and to compare isolation rates among various tissues collected at the abattoir. Market swine from an Iowa farrow- to-finish operation with ~ 600 sows. Tested 30 market-bound pigs (~ 240 lbs) on each of 10 occasions. All pigs were slaughtered and samples collected at a large midwest abattoir. Fecal samples were collected from market pigs on the farm. Pigs were alternately assigned to a lairage treatment group or a control group (remain on the farm). After ~ 18 hours, both groups were transported (~ 85 miles) to a large midwest abattoir and commingled. After slaughter, samples were collected for culture of Salmonella (feces from the distal colon, ileocecal lymph nodes, cecal contents, ventral thoracic lymph nodes, subiliac lymph nodes, carcass swabs), diaphragm sections were collected for serum ELISA. Salmonella enterica derby was the only serotype isolated from farm fecal samples 3.4% (10/290). Multiple serotypes (n = 17) were isolated from 71.8% (196/273) of the pigs when abattoir collected samples were cultured: cecal contents (21.2%, 58/273), distal colon contents (52%, 142/273), and ileocecal lymph nodes (43.6% 119/273). There were lower Salmonella isolation rates from the lairaged pigs (P < 0.05). The predominate serotype isolated varied by week of the study. This study suggests that pigs became internally contaminated with Salmonella, after leaving the farm, possibly while in the abattoir holding pens, and that ~ 18 hours lairage, in clean facilities, does not increase shedding.