title: Survival and germination of Clostridium perfringens spores during heating and cooling of ground pork.
abstract: The effect of heating rate on the heat resistance, germination, and outgrowth of Clostridium perfringens spores during cooking of cured ground pork was investigated. Inoculated cured ground pork portions were heated from 20 to 75°C at a rate of 4, 8, or 12°C/h and then  held at 75°C for 48 h. No significant differences (P > 0.05) in the heat resistance of C. perfringens spores were observed in cured ground pork heated at 4, 8, or 12°C/h. At heating rates of 8 and 12°C/h, no significant differences in the germination and outgrowth  of spores were observed (P > 0.05). However, when pork was heated at 4°C/h, growth of C. perfringens occurred when the temperature of the product was between 44 and 56°C. In another set of experiments, the behavior of C. perfringens spores under temperature  abuse conditions was studied in cured and noncured ground pork heated at 4°C/h and then cooled from 54.4 to 7.2°C within 20 h. Temperature abuse during cooling of noncured ground pork resulted in a 2.8-log CFU/g increase in C. perfringens. In cured ground pork, C. perfringens  decreased by 1.1 log CFU/g during cooling from 54.4 to 36.3°C and then increased by 0.9 log CFU/g until the product reached 7.2°C. Even when the initial level of C. perfringens spores in cured ground pork was 5 log CFU/g, the final counts after abusive cooling did not exceed  3.4 log CFU/g. These results suggest that there is no risk associated with C. perfringens in cured pork products under the tested conditions.
authors.affiliation: Center for Food Safety, Department of Animal Science, Texas AgriLife Research, Texas A&M University, College Station, TX 77843-2471, USA.
authors.forename: M
authors.initials: M
authors.lastname: Márquez-González
authors.forename: E
authors.initials: E
authors.lastname: Cabrera-Díaz
authors.forename: M D
authors.initials: MD
authors.lastname: Hardin
authors.forename: K B
authors.initials: KB
authors.lastname: Harris
authors.forename: L M
authors.initials: LM
authors.lastname: Lucia
authors.forename: A
authors.initials: A
authors.lastname: Castillo
mesh_terms: D000818:Animals; D003016:Clostridium perfringens / Q000502:physiology*; D003080:Cold Temperature; D015169:Colony Count, Microbial; D003257:Consumer Product Safety; D005506:Food Contamination / Q000032:analysis / Q000517:prevention & control; D005511:Food Handling / Q000379:methods*; D006358:Hot Temperature; D006801:Humans; D008461:Meat Products / Q000382:microbiology*; D050296:Microbial Viability; D013171:Spores, Bacterial; D013552:Swine