Modelling the combined effect of salt, sorbic acid and nisin on the probability of growth of Clostridium sporogenes in high moisture processed cheese analogue

This study focused on the application of hurdle technology to inhibit the growth of Clostridium sporogenes in high moisture, low salt, ambient shelf-stable processed cheese analogue (PCA). The effectiveness of various combinations of salt, potassium sorbate and nisin in inhibiting C. sporogenes growth was quantified using logistic regression to produce probability-of-growth models. The results of this study demonstrate that it is feasible to produce a high moisture and low salt PCA, if sufficient concentrations of potassium sorbate and nisin are added to the product. Any change in the concentration of one of the selected preservatives must be compensated for by changes in concentrations of the other two preservatives. The models developed enable the level of probability to be set to provide a required level of stringency. The models tend to be fail-safe as they were developed using an inoculum size larger than the expected contamination in processed cheese.