L Duffy1, G A Dykes. 1. Food Science Australia, Tingalpa DC, Qld, Australia.
Abstract
AIM: To determine if Campylobacter jejuni grown at 37 and 42 degrees C have different abilities to survive on beef and chicken, and in water. METHODS AND RESULTS: Beef, chicken and water were separately inoculated with four Camp. jejuni (two poultry and two beef) strains grown at 37 or 42 degrees C. The matrices were stored at approximately 4 degrees C and Camp. jejuni numbers were monitored over time by plate counts. On beef there was a greater decrease in number for two strains (P < 0.05; approximately 0.7 and 1.3 log CFU cm(-2)) grown at 37 degrees C as compared with 42 degrees C. By contrast on chicken there was a decrease in numbers for two strains (P < 0.05; approximately 1.3 and 1 log CFU g(-1)) grown at 42 degrees C as compared with 37 degrees C. In water there was a greater decrease in numbers for all strains (P < 0.05; approximately 3-5.3 log CFU ml(-1)) grown at 42 degrees C as compared with 37 degrees C. CONCLUSIONS: Growth temperature influences the survival of Camp. jejuni on food and in water. SIGNIFICANCE AND IMPACT OF THE STUDY: Campylobacter jejuni survival studies need to consider growth temperature to avoid erroneous results. Campylobacter jejuni grown at 37 degrees C, the body temperature of humans and cattle, may represent a greater public health risk in water than those grown at 42 degrees C, the body temperature of poultry.
AIM: To determine if Campylobacter jejuni grown at 37 and 42 degrees C have different abilities to survive on beef and chicken, and in water. METHODS AND RESULTS: Beef, chicken and water were separately inoculated with four Camp. jejuni (two poultry and two beef) strains grown at 37 or 42 degrees C. The matrices were stored at approximately 4 degrees C and Camp. jejuni numbers were monitored over time by plate counts. On beef there was a greater decrease in number for two strains (P < 0.05; approximately 0.7 and 1.3 log CFU cm(-2)) grown at 37 degrees C as compared with 42 degrees C. By contrast on chicken there was a decrease in numbers for two strains (P < 0.05; approximately 1.3 and 1 log CFU g(-1)) grown at 42 degrees C as compared with 37 degrees C. In water there was a greater decrease in numbers for all strains (P < 0.05; approximately 3-5.3 log CFU ml(-1)) grown at 42 degrees C as compared with 37 degrees C. CONCLUSIONS: Growth temperature influences the survival of Camp. jejuni on food and in water. SIGNIFICANCE AND IMPACT OF THE STUDY: Campylobacter jejuni survival studies need to consider growth temperature to avoid erroneous results. Campylobacter jejuni grown at 37 degrees C, the body temperature of humans and cattle, may represent a greater public health risk in water than those grown at 42 degrees C, the body temperature of poultry.