Potential for the cross-contamination of the hides of cattle while they are held in lairage

Abstract

Foodborne pathogens that may contaminate the carcase are often found on the hides of cattle presented for slaughter for human consumption, and can be transferred from animal to animal during the immediate preslaughter phase. This study quantifies the opportunities for such cross-contamination to occur during lairage of cattle. Cattle were most active in the first 10 minutes of holding, when at 2·5 m² or less space allowance per animal there were 12·55 animal-to-animal and 0·99 animal-to-wall contacts per minute, compared with 8·17 and 0·60 per minute, respectively, in the subsequent 20 minutes. During holding, contact between animals can be reduced by manipulating the stocking density. When the animals were given 2·5 m² or more each, there were 9·63 animal-to-animal contacts per minute over 30 minutes holding, whereas at 5 m² or more, there were only 1·71 contacts per minute. Whatever the space allowance, animal-to-wall contacts were 0·66 to 0·73 per minute over 30 minutes' holding. When space allowance is optimised, contacts with the lairage structure become more important than contacts between animals. The immediate preslaughter handling equipment (race, crush and stun box) was a significant source of potential indirect cross-contamination.