title: Effect of antemortem feeding regimes on bacterial numbers in the stomachs and ceca of pigs.
abstract: Three groups, each of 45 pigs, were either not fasted, fasted for 15 h during lairage at the abattoir, or fasted for 15 h before dispatch from the piggery to the abattoir. Three subgroups, each of 15 pigs from each group, were held at the abattoir for additional times of either 0 to 1 h, 2 to 3 h, or 4 to 5 h. Immediately after slaughter, stomach and cecal contents were collected for pH measurement and enumeration of coliforms, Escherichia coli biotype 1 and lactic acid bacteria (LAB). Stomach pH changed from 4.1 to 3.1 as additional abattoir holding time increased from 0 to 1 h to 4 to 5 h but was unaffected by feed withdrawal (mean pH, 3.5). Cecal pH (range 6.4 to 7.2) increased in response to both treatments. Coliform and E. coli biotype 1 numbers in the stomach, means 4.6 and 4.5 log CFU/g, respectively, were not affected by feed withdrawal but decreased 0.8 log units as additional abattoir holding time increased from 0 to 1 to 4 to 5 h. LAB in the stomach decreased in response to both feed withdrawal and holding at the abattoir. Cecal numbers of coliforms and E. coli biotype 1 increased 0.8 and 1.0 log units to 7.8 and 7.6 log CFU/g, respectively, as a result of feed withdrawal, and 0.6 log units to 7.6 and 7.5 log CFU/g, respectively, as additional abattoir holding time increased to 4 to 5 h. The LAB in the cecum (mean 9.4 log CFU/g) increased slightly with increasing abattoir holding time. In the event of release of stomach or cecal contents onto the meat during carcass dressing, larger numbers of E. coli per g would be released from the ceca and fewer per g from the stomachs of pigs that have had feed withdrawn as compared to pigs not subjected to feed withdrawal.
authors.affiliation: Agriculture and Agri-Food Canada, Lacombe Research Centre, C&E Trail, Alberta. nattressf@em.agr.ca
authors.forename: F M
authors.initials: FM
authors.lastname: Nattress
authors.forename: A C
authors.initials: AC
authors.lastname: Murray
mesh_terms: D000003:Abattoirs; D000818:Animals; D002432:Cecum / Q000382:microbiology*; D015169:Colony Count, Microbial; D004755:Enterobacteriaceae / Q000254:growth & development* / Q000302:isolation & purification; D004926:Escherichia coli / Q000254:growth & development / Q000302:isolation & purification; D005508:Food Deprivation / Q000502:physiology*; D006863:Hydrogen-Ion Concentration; D012486:Salmonella typhimurium / Q000254:growth & development / Q000302:isolation & purification; D013270:Stomach / Q000382:microbiology*; D013552:Swine / Q000382:microbiology* / Q000502:physiology; D013997:Time Factors