The growth, survival and thermal inactivation of escherichia coli O157:H7 in a traditional South African sausage

04 Feb 2017

This study investigated the growth and survival of Escherichia coli O157:H7 inoculated into boerewors models with (B+P) and without (B?P) sulphur dioxide preservative at a low (L) and high (H) inoculum followed by storage at 0, 4 and 10?C for 10days. The pathogen?s thermal inactivation at 50, 60, 65 and 70?C was also evaluated in B+P. The B?P at both low and high inocula had significantly higher recoveries at all temperatures compared to B+P. The BL+P and BH+P had significant reductions in recoveries at 0?C, declining to below detectable limits at days 8 and 10, respectively. At 4?C, the BL+P and BH+P recoveries declined significantly at day 10. At 10?C, significant increases were observed from days 0 to day 10 in both models and at low and high inocula. At 0?C, the BL?P and BH?P treatments had significant declines in recoveries. The combination of sulphur dioxide preservative and low temperature demonstrated the best efficacy against E. coli O157:H7 survival. Thermal inactivation of E. coli O157:H7 was 60min at 60?C, 80 s at 65?C and 60s at 70?C. This study demonstrated that E. coli O157:H7 can survive in boerewors with and without preservative and is more sensitive to heat treatment at 70?C.