Predicting the Concentration of Verotoxin-Producing Escherichia coli Bacteria during Processing and Storage of Fermented Raw-Meat Sausages

Abstract

A model to predict the population density of verotoxigenic Escherichia coli (VTEC) throughout the elaboration and storage of fermented raw-meat sausages (FRMS) was developed. Probabilistic and kinetic measurement data sets collected from publicly available resources were completed with new measurements when required and used to quantify the dependence of VTEC growth and inactivation on the temperature, pH, water activity (a w ), and concentration of lactic acid. Predictions were compared with observations in VTEC-contaminated FRMS manufactured in a pilot plant. Slight differences in the reduction of VTEC were predicted according to the fermentation temperature, 24 or 34°C, with greater inactivation at the highest temperature. The greatest reduction was observed during storage at high temperatures. A population decrease greater than 6 decimal logarithmic units was observed after 66 days of storage at 25°C, while a reduction of only ca. 1 logarithmic unit was detected at 12°C. The performance of our model and other modeling approaches was evaluated throughout the processing of dry and semidry FRMS. The greatest inactivation of VTEC was predicted in dry FRMS with long drying periods, while the smallest reduction was predicted in semidry FMRS with short drying periods. The model is implemented in a computing tool, E. coli SafeFerment (EcSF), freely available from http://www.ifr.ac.uk/safety/EcoliSafeFerment. EcSF integrates growth, probability of growth, and thermal and nonthermal inactivation models to predict the VTEC concentration throughout FRMS manufacturing and storage under constant or fluctuating environmental conditions.

Health and Safety Considerations of Fermented Sausages

“…A dynamic model to predict VTEC concentration throughout manufacturing and storage of fermented raw meat sausages has been developed by Quinto et al [288]. The model is implemented in a tool called E. coli SafeFerment (EcSF), available at http://www.ifr.ac.uk/safety/EcoliSafeFerment.…”

Toxins in Fermented Foods: Prevalence and Preventions—A Mini Review

“…The computing tool was named EcSF (E. coli safeFerment), and it is freely available. The developers argued that EcSF could be a reliable computational method to monitor the FRMS during processing and storage [56].…”

Control of Listeria monocytogenes in chicken dry-fermented sausages with bioprotective starter culture and high-pressure processing

“…However, for ST, the model provides faildangerous predictions (inactivation), while growth or no change of L. monocytogenes was observed. According to meta-analyses performed by several authors regarding the inactivation rate of bacterial pathogens during sausage fermentation and ripening, the temperature explains most (60-80%) of the variability and, under growth-preventing conditions, determines the reduction of L. monocytogenes (Mataragas et al, 2015) and E. coli (Ross and Shadbolt, 2001;Ross et al, 2008;Quinto et al, 2014). In these studies, the influence of pH, a w or other specific factors (e.g., bacteriocins) cannot be discerned from the background noise of all collated data originating from a wide variety of experiments, including different types of products, processes, bacterial strains, etc.…”