Scientific Publications
Predicting the concentration of verotoxin-producing Escherichia coli during processing and storage of fermented raw meat sausages
Applied and Environmental Microbiology, 80(7), 2715-2727
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 datasets 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, aw, 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 25ºC while only ca. 1 logarithmic unit reduction was detected at 12ºC. The performance of our model and other modelling approaches were evaluated throughout the processing of dry and semi-dry FRMS. The greatest inactivation of VTEC was predicted in dry FRMS with long drying periods while the smallest reduction was predicted in semi-dry 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 non-thermal inactivation models to predict VTEC concentration throughout FRMS manufacturing and storage under constant or fluctuating environmental conditions.
Applied and Environmental Microbiology, 80(7), 2715-2727
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