The effect of chilling broiler carcasses in cold air or ice water on the population of Campylobacter

Authors: Berrang, Mark; Meinersmann, Richard - Rick

Submitted to: Campylobacter Helicobacter and Related Organisms International Workshop
Publication Type: Abstract Only
Publication Acceptance Date: 6/7/2007
Publication Date: 9/1/2007
Citation: Berrang, M.E., Meinersmann, R.J. 2007. The effect of chilling broiler carcasses in cold air or ice water on the population of Campylobacter [abstract]. Campylobacter Helicobacter and Related Organisms International Workshop. 54(supp1):124.

Interpretive Summary:

Technical Abstract: Broiler carcasses from a Campylobacter positive flock may remain contaminated with Campylobacter after processing. Most broiler companies in the U.S. use an ice water immersion method to bring carcasses down in temperature; air chilling of broiler carcasses is more common in Europe. The objective of this study was to compare the numbers, species, subtype and antimicrobial susceptibility of Campylobacter on broiler carcasses chilled in an ice water bath to those chilled by hanging in a cold room. Pre-chill broiler carcasses were collected at a commercial processing plant and transported to the laboratory without ice. All carcasses were cut in half along the dorsal/ventral midline. One half of each carcass was subjected to an ice water immersion chill in an agitated bath for 50 min. The corresponding half of each carcass was subjected to an air chill by hanging in shackles in a 1o C cold room for 150 min. Campylobacter was enumerated from half carcass rinses. Two isolates per carcass half were chosen for determination of species by a commercial PCR method, molecular subtyping by PFGE after restriction using Sma I and determination of antimicrobial susceptibility by a broth micro-dilution method. Log10 2.40 cfu Campylobacter were detected per ml rinse of air chilled carcass halves; significantly less, log10 1.81 cfu, were detected per ml from immersion chilled carcasses. Species detected included jejuni and coli; within each replication these species were recovered in the same proportion from carcasses subjected to each chilling method. In some instances, both species were recovered from the same carcass half. Results of the PFGE subtyping do not suggest that either chilling method selects for any specific subtypes; most subtypes were found on carcass halves used for both air and water immersion chill. Resistance to antimicrobial drugs was only observed in one replication and only in C. coli. Six isolates from air chilled carcass halves and three from immersion chilled carcass halves were resistant to ciprofloxacin and nalidixic acid. These data show that immersion chilled carcasses have slightly lower numbers of Campylobacter; however, the difference is not large and may be due to simple dilution. Both methods are effective for lowering carcass temperature and seem to affect Campylobacter similarly.