Evaluation of the Listeria monocytogenes inactivation during post-process storage of fermented sausages: A basis for the development of a decision support tool

In situ quantitative data on Listeria monocytogenes survival during storage of vacuum-packaged fermented sausages at various temperatures were collected from the literature to develop a generic predictive model regarding its fate at a specific storage temperature. The development of the tool was based on the z-concept. The time needed for 4D reduction of the pathogen was estimated and its influence by the temperature was further described by linear regression. A secondary model was developed for describing the effect of sausage water activity on the z-concept parameters at the reference temperature. The decision support tool was successfully validated against the studies not used during the development of the model. Based on the model predictions, a decision can be made about the required time of product storage before its distribution to achieve an additional pathogen inactivation. Such tools can be incorporated in a HACCP plan of a food-producing company to assure food safety. © 2014 Elsevier Ltd

Estimating the non-thermal inactivation of Listeria monocytogenes in fermented sausages relative to temperature, pH and water activity

Data relative to in situ Listeria monocytogenes inactivation in fermented sausages were collected from 13 individual studies found in the literature. Inactivation rates were extrapolated and used to develop a predictive model to evaluate the relative effects of pH, water activity (aw) and temperature on L. monocytogenes fate during fermentation and ripening. Temperature explained ca. 60% of the data variability, while pH and aw only a small part. Temperature alone may not be sufficient to cause pathogen's inactivation, but inactivation rate is dominated by temperature when pH and aw are in the range which prevent L. monocytogenes growth. A predictive model based on two Arrhenius equations (ln[inactivation rate]=-25.71-[-0.6829/(8.314×T)] for fermentation; and ln[inactivation rate]=-44.86-[-1.219/(8.314×T)] for ripening) was developed. The model can be used to quantify the effect of temperature and/or time changes on fermented sausage safety. The advantages and limitations of the model are discussed. © 2014 Elsevier Ltd