Growth responses of Salmonella Enteritidis subjected to heat or high pressure treatment in a laboratory medium

Abstract

Salmonella Enteritidis culture was subjected to heat or high pressure treatment to obtain bacteria reduction by 4, 5 and 6 log units. Control, heated and pressurized microorganisms were incubated in nutrient broth at 10 °C and 20 °C. Growth curve parameters were calculated using the Gompertz equation. It was found that untreated salmonellae had a shorter generation time and a higher exponential growth rate than heated and pressurized bacteria incubated at 10 °C. Pressurized bacteria had a slightly shorter lag time and generation time than heated ones, but the differences between heated and pressurized salmonellae were not large enough to be statistically significant. Growth curve values (lag time, generation time, exponential growth rate, maximum population density) for all experimental groups of salmonellae incubated at 20 °C did not differ statistically.

Keywords:

• high-pressure processing (HPP)
• heat treatment
• Salmonella Enteritidis
• bacterial growth curve
• Gompertz equation