Service temperature preservation approach for food safety: Microbiological evaluation of ready meals

Abstract

Microbial food contamination can take place in any step of food production from farms to factories and to retail, food services and storage, originating from different sources such as raw materials, operators and environmental conditions of manufacturing plant. To avoid the range of temperature called “danger zone” (5°C–57 °C), occurring during food cooling, and to block microbial contamination post cooking, food service temperature preservation was evaluated in this study by an unconventional approach. This consists in the maintenance of ready meals at temperatures above 60 °C, for long periods, and not just for less than 2 h as commonly used, before their consumption. Applying this preservation method to different food preparations, the pathogenic contamination was controlled. In particular, L. monocytogenes was absent in 25 g in all samples, and E. coli, included O 157:H7, was under the detection threshold (1 Log CFU/g). Furthermore, different thermal abuses were simulated and, overall, service temperature preservation maintained the microbiological contamination under control. The microbial concentration did not increase in the most of the tested cases. Only S. aureus and B. cereus were observed in concentration lower than 1.5 Log CFU/g and only after 24 h at room temperature some critical situations were observed due to their presence near to 5 Log CFU/g. Microbiological challenge tests, simulating food contaminations after preparation, were also performed to monitor microbial behaviour during service temperature preservation. So, this work proposed a valid alternative to cold storage ensuring safety food products stored with service temperature preservation.