Parameters of Growth Curves of Salmonella Enteritidis Subjected to Conventional Heat or Microwave Treatment

Salmonella Enteritidis culture was subjected to heat or microwave treatment to obtain bacteria reduction by 4, 5, and 6 log units. Control, heated and microwaving micro-organisms were incubated in a nutrient broth at 10°C for 432 h. Growth-curve parameters were calculated using Gompertz and Baranyi equations. It was found that in most cases untreated salmonellae had a shorter generation time, a higher exponential growth rate, and a higher maximum growth rate than heated and microwaving bacteria. Growth of bacteria subjected to microwave treatment was more dynamic than that of bacteria subjected to conventional heating. It was expressed by statistically-significant differences in generation time and exponential growth rate calculated by the Gompertz equation, as well as maximum growth rate calculated by the Baranyi model for both compared groups of salmonellae.