Weibull’s distribution application on Escherichia coli, Staphylococcus aureus and Bacillus cereus survival evaluation

Abstract

Microbiological control in food production aims to provide consumer safe products by preventing the development of foodborne pathogens with a suitable process of heating, cooling, or reheating food. The aim if this work was to evaluate the survival of Escherichia coli, Staphylococcus aureus and Bacillus cereus in soup using the Weibull’s distribution at different temperatures. Samples of Soup were inoculated with each of these microorganisms, incubated at three different temperatures (40, 50, and 60 °C) and analyzed at different time intervals. With the data obtained, growth curves were obtained and adjusted to the Weibull’s distribution. Growth kinetic studies showed that all microorganisms can develop and reproduce satisfactorily at 40 °C, however, at 50 °C the bacterial load was maintained for a short time and then began to drop without reaching death. Finally,at 60 °C bacteria decreased sharply until reaching death. The Weibull’s distribution analysis indicates that, at the end of each experiment, surviving bacteria remain, thus corroborating that they possess adaptive mechanisms that are activated when they undergo stressful conditions. The ideal temperature to keep cooked food in microbiological safe conditions is above 60 °C. Below this temperature some microorganisms remain viable.