Submitted to: Applied and Environmental Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 1, 2003
Publication Date: April 6, 2003
Citation: SOLOW, B.T., CLOAK, O.M., FRATAMICO, P.M. EFFECT OF TEMPERATURE ON VIABILITY OF CAMPYLOBACTER JEJUNI AND CAMPYLOBACTER COLI ON CHICKEN AND PORK SKINS. APPLIED AND ENVIRONMENTAL MICROBIOLOGY. Vol. 66, No. 11, 2003, Pages 2023-2031 Interpretive Summary: The most common cause of bacterial food poisoning in the world is infection by Campylobacter. These bacteria are found primarily on foods of animal origin namely poultry and pork. All of the environmental conditions that permit Campylobacter to grow or survive on chicken and pork are not known. Our understanding of the behavior of this bacterium under different conditions will permit the development of strategies to control Campylobacter in foods. Therefore, the viability of Campylobacter was examined at freezing temperatures, refrigeration temperatures, and room temperature on chicken and pork skins. Campylobacter survived better at refrigeration temperatures than at freezing or room temperatures on both chicken and pork skins. This finding is of concern to the poultry and pork processors as meat is commonly stored at refrigeration temperatures prior to cooking. However, Campylobacter were rapidly killed when chicken and pork skins were frozen. Therefore, freezing meat instead of storing it in the refrigerator is an effective way to reduce the number of Campylobacter on chicken and pork.
Technical Abstract: To determine the viability of Campylobacter on chicken and pork skins, the skins were inoculated with Campylobacter jejuni or Campylobacter coli and exposed to temperatures ranging from -20 to 42 deg C under either microaerophilic or aerobic conditions. Viable counts over 48 hours declined 2 to 3 log 10 CFU/g at -20 deg C, 1 log 10 CFU/g at 4 deg C, and 1 1to 2 log 10 CFU/g at 25 deg C regardless of skin type, species of Campylobacter, or level of oxygen. At both 37 and 42 deg C, the number of viable Campylobacter increased to the point of saturation (approximately 10**7 CFU/g) under microaerophilic conditions but decreased 1 to 2 log 10 CFU/g in air. Pre-incubation of skins for 24 hours at 42 deg C under microaerophilic conditions to establish Campylobacter on the surface prior to lowering the temperature to -20, 4, or 25 deg C had no effect on viability compared to incubation at -20, 4, or 25 deg C without pre- incubation. Pre-incubation of inoculated skins at -20, 4, or 25 deg C for 24 hours followed by a shift in temperature to 42 deg C for 4, 8, 24, or 48 hours and a shift to microaerophilic conditions resulted in an overall decline in viability on pork skins but not on chicken skins. In contrast, pre-incubation of inoculated skins at -20, 4, or 25 deg C for 24 hours followed by a shift in temperature to 37 deg C and microaerophilic conditions did not result in a decrease in viable counts for either chicken or pork skins. Overall, under the conditions tested on chicken and pork skins, there was no difference in viability between C. coli and C. jejuni and little difference in viability of Campylobacter between the two types of skin.