There is considerable debate regarding the benefit to be obtained by routine testing of foods for the presence of Campylobacter and establishing performance standards as part of the food safety system.
The emergence of this human pathogen appears to warrant this action. Campylobacter species are reportedly responsible for more than 14% of the estimated annual food-related illness and death rates attributed to known foodborne pathogens. Campylobacter jejuni accounts for an estimated 2 million cases of foodborne illness annually, with poultry and unpasteurized milk as its principal vehicles. The incidence rates reported in retail poultry have historically ranged from 2% to 98% of carcasses tested, while more recent reports indicate that 60–90% of retail carcasses contain levels greater than 103 cfu/g.
The wide variation reported in the prevalence of this human pathogen indicates the lack of a generally accepted method for its isolation and recovery on a consistent basis. Although several well-respected laboratories have invested significant energy and resources to develop reliable and accurate methods, a clear standard method has not been established. The organism is very difficult to isolate and culture with accuracy and precision from live animals and foods from these sources, and USDA’s Food Safety and Inspection Service (FSIS) recently asked the National Advisory Committee on Microbiological Criteria for Food (NACMCF) to review the methodologies used for Campylobacter detection in the 1994–95 and 1999–2000 baseline studies in young chickens and compare them to recent advances in methodologies.
The more critical issue, however, is that the ecology of the organism is not well defined. C. jejuni is carried in the intestinal tract of apparently healthy poultry and livestock. Fecal contamination of feathers, skin, and hides occurs during poultry and livestock production and slaughter, with potential for contamination during processing. The environmental sources of Campylobacter are not clearly established. As a result of this lack of understanding, no proven intervention strategies are currently available for use by producers and processors for reduction and control of this pathogen.
The incidence of Salmonella has been effectively reduced in meat and poultry products since the implementation of FSIS’s Salmonella performance standards in 1998. The primary reason is that the ecology of this organism is better understood and proven intervention strategies have been developed. Salmonella is the most thoroughly investigated food-related pathogen, having been the subject of intense scrutiny for more than 50 years. As a result, multiple strategies are available to be employed in a series of hurdles which effectively reduce the presence of the organism in meat and poultry products. That is not the case with Campylobacter. At the same time, increased water usage and attention to elimination of fecal contamination prior to the chilling process has washed enough Salmonella from the carcasses to contribute to this difference.
During this period of progress in Salmonella reduction associated with meat and poultry, the incidence of Campylobacter has increased in both product recovery and foodborne illness rates. Although this may be associated with improved methodology for detection of Campylobacter and increased awareness by laboratories and diagnosis by the medical community, it nevertheless supports the position that traditional reduction strategies employed for Salmonella reduction and control are not effective for Campylobacter. Is the effort in Salmonella reduction creating an environment conducive to the emergence of Campylobacter?
The role of performance standards in the food safety system is being evaluated by two select panels composed of the leading scientists engaged in microbiology and food safety research and education. The National Academy of Sciences panel is expected to report the results of its deliberations later this year. NACMCF is also conducting a review of the use of performance standards and has issued an interim (preliminary) report, while assembling additional information.
In summary, the adoption of performance standards for Campylobacter prior to the availability of (1) standard methodology for isolation and culture and (2) proven intervention strategies for reduction and control would be premature. The research data required to justify adopting performance standards is simply not available yet.
by James H. Denton is Professor, Dept. of Poultry Science, University of Arkansas, Fayetteville.