科研之友
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摘要
Consumer demand is increasing for free-range and organic poultry products. The USDA requires that postchill broilers be tested for Escherichia coli, Salmonella, and Campylobacter. Microbiological data are limited on the fast-growing Cornish cross (CX) chickens or the medium-growing Freedom Rangers (FR), 2 predominant strains of pastured broilers grown in the Southeast region of the United States. The objective of the present study was to compare the levels of total coliforms and E. coli, as well as the prevalence of Campylobacter and Salmonella, in pastured CX and FR strains. In each of 2 trials, 40 CX and 40 FR broilers were raised together on pasture with water and supplemental feed. At market weight, birds were processed and 20 prechill carcasses of each strain were evaluated for enumeration of total coliforms and E. coli, as well as the prevalence of Salmonella. Cecal contents were direct plated for Campylobacter detection. Mean counts for total coliforms and E. coli (expressed in log cfu/mL) were 3.8 and 3.4 for FR, which was significantly lower (P %26lt; 0.05) than the 4.1 and 3.7 for the CX group. The Salmonella prevalence on carcasses was not different in trial 1 because of strain, but the FR strain had significantly lower Salmonella than the CX strain (50 vs. 100%, respectively) in trial 2. Irrespective of strain, the prevalence of Campylobacter was high (95% for FR vs. 100% for CX). In trial 2, although the medium-growing FR showed lower levels of total coliforms and E. coli, as well as a lower prevalence of Salmonella, even when reared with fast-growing CX, it is not known whether this could have been due to an inherent ability of FR to resist colonization or the benefit from longer residence on pasture.
- 出版日期2012-9
