About Campylobacter

From the nation’s leading law firm representing victims of Campylobacter and other foodborne illness outbreaks.

Chapter 3

The Prevalence of Campylobacter in Food and Elsewhere

How prevalent is Campylobacter food contamination?

Although most cases of Campylobacter infection in humans are sporadic, a substantial number of outbreaks—30 outbreaks by one report, and 50 by another—have been linked to the consumption of unpasteurized (raw) milk. [1, 5]

Since 1992, food remains the most common vehicle for the spread of Campylobacter, and chicken is the most common food implicated. [5, 25, 28] As one authority points out, “commercially raised poultry is nearly always colonized with C. jejuni, slaughterhouse procedures amplify contamination, and chicken and turkey in supermarkets, ready for consumers to take home, frequently is contaminated.” [5] Similarly, prominent USDA researchers have noted:

Most retail chicken is contaminated with C. jejuni; one study reported an isolation rate of 98% for retail chicken meat. C. jejuni counts often exceed 103 per 100 g. Skin and giblets have particularly high levels of contamination. In one study, 12% of raw milk samples from dairy farms in eastern Tennessee were contaminated with C. jejuni. Raw milk is presumed to be contaminated by bovine feces; however, direct contamination of milk as a consequence of mastitis also occurs. Campylobacters are also found in red meat. In one study, C. jejuni was present in 5% of raw ground beef and in 40% of veal specimens. [1]

Since 1998, the publisher of Consumer Reports magazine has conducted surveys and tested chicken at retail for Salmonella and Campylobacter. While the first study identified Campylobacter in 63% of more than 1000 chickens obtained in grocery stores, a 2009 study found only a 1% improvement, with 62% of the 382 chickens tested positive for Campylobacter. [14] A USDA Baseline Data Collection Program done in 1994 documented Campylobacter contamination on 88.2% of broiler-chicken carcasses [30]. Subsequent USDA data collection has shown an estimated 46.7% prevalence of Campylobacter in chicken [31], and 1.46% in turkeys. [32] Campylobacter is also prevalent in wild birds of all kinds. [1, 5]

As already noted, contamination occurs during slaughter and processing when meat comes into contact with animal feces. Consequently:

Slaughter and processing provide opportunities for reducing C. jejuni counts on food-animal carcasses. Bacterial counts on carcasses can increase during slaughter and processing steps. In one study, up to a 1,000-fold increase in bacterial counts on carcasses was reported during transportation to slaughter. In studies of chickens and turkeys at slaughter, bacterial counts increased by approximately 10- to 100-fold during defeathering and reached the highest level after evisceration. However, bacterial counts on carcasses decline during other slaughter and processing steps. In one study, forced-air chilling of swine carcasses caused a 100-fold reduction in carcass contamination. In Texas turkey plants, scalding reduced carcass counts to near or below detectable levels. Adding sodium chloride or trisodium phosphate to the chiller water in the presence of an electrical current reduced C. jejuni contamination of chiller water by 2 log10 units. In a slaughter plant in England, use of chlorinated sprays and maintenance of clean working surfaces resulted in a 10- to 100-fold decrease in carcass contamination. In another study, lactic acid spraying of swine carcasses reduced counts by at least 50% to often undetectable levels. A radiation dose of 2.5 KGy reduced C. jejuni levels on retail poultry by 10 log10 units. [1]

Further, with poultry, contamination levels peak during the summer months [1, 5, 28], and this seasonal pattern is reflected in the number of reported Campylobacter infections. [5, 28]

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