Bacterial Contamination of Broiler Chickens before Scalding

Abstract

The bacterial load on the feathers (breast, thigh, and drum), skin (breast, thigh, and drum), and feet of a total of 40 broiler chickens from four different production units was characterized after the chickens were exsanguinated but before the carcasses were scalded. Each broiler carcass contained a mean of aerobic bacteria at or near 8log10/g, a level at which the carcasses would be considered spoiled. Escherichia coli counts ranged from 6.3 to 8.0 log10/g, with the highest presence on the feathers and breast skin and lower levels on the thigh and drum skin, and feet. Contamination of the carcasses followed a similar pattern for Salmonella spp., which ranged between 5.8 and 7.2 log10/g, and Campylobacter jejuni/coli which ranged between 6.1 and 7.5 log10/g. The incidence of potential pathogens was higher on the feathers, breast skin, and feet than on the thigh and drum skin. The incidence of E. coli ranged from 42.5 to 100%, Salmonella spp. ranged from 27.5 to 75%, and C. jejuni/coli ranged from 45 to 82.5%. The mean counts of microorganisms on broilers from the four different grow-out farms were significantly different (P > 0.05) from one another immediately after killing, although the magnitude of the differences was small in most cases. The means ranged from 7.3 to 8.0 log10/g for total colony-forming units (CFU), 6.7 to 7.6 log10/g for E. coli, 5.4 to 6.9 for Salmonella spp., and 5.7 to 7.9 for C. jejuni/coli. All birds were contaminated with E. coli, 60 to 100% with Salmonella spp., and 80 to 100% with C. jejuni/coli, depending on grow-out farm. C. jejuni/coli counts and incidences were higher than those of Salmonella spp., and usually lower than those of E. coli. This research demonstrates that broilers entering the processing plant are highly contaminated. Although processing seems to decrease the number and incidence of microorganisms on the carcasses, additional modifications in production, transportation, and processing are warranted to reduce the microbial population on the birds before they are slaughtered.