title: The growth, survival and thermal inactivation of Escherichia coli O157:H7 in a traditional South African sausage.
abstract: 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 degrees C for 10 days. The pathogen's thermal inactivation at 50, 60, 65 and 70 degrees 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 degrees C, declining to below detectable limits at days 8 and 10, respectively. At 4 degrees C, the BL+P and BH+P recoveries declined significantly at day 10. At 10 degrees C, significant increases were observed from days 0 to day 10 in both models and at low and high inocula. At 0 degrees 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 60 min at 60 degrees C, 80 s at 65 degrees C and 60s at 70 degrees 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 degrees C.
authors.affiliation: Department of Microbial, Biochemical and Food Biotechnology, University of the Free State, PO Box 339, Bloemfontein 9300, South Africa.
authors.forename: G
authors.initials: G
authors.lastname: Charimba
authors.forename: C J
authors.initials: CJ
authors.lastname: Hugo
authors.forename: A
authors.initials: A
authors.lastname: Hugo
mesh_terms: D000818:Animals; D002417:Cattle; D003080:Cold Temperature; D019453:Escherichia coli O157 / Q000187:drug effects / Q000254:growth & development*; D005516:Food Microbiology; D005519:Food Preservation / Q000379:methods*; D006358:Hot Temperature; D008461:Meat Products / Q000382:microbiology*; D050296:Microbial Viability / Q000187:drug effects; D013458:Sulfur Dioxide / Q000494:pharmacology*; D013552:Swine; D013696:Temperature
chemical_list: D013458:Sulfur Dioxide