Modeling the effects of sucuk production technique on Listeria monocytogenes, aerobic bacteria and lactic acid bacteria during ripening and storage

Abstract

The modeling of sucuk (Turkish dry-fermented sausage) production techniques on the survival of Listeria monocytogenes, aerobic bacteria (AB), lactic acid bacteria (LAB), and yeasts and molds (YM) during ripening and storage periods were studied. Effect of L. monocytogenes initially contaminated level (low, medium and high contaminated levels) with sucuk dough was also studied. Survival data were analyzed by non-linear regression of modified-Gompertz and logistic equations to generate “best fit”. L. monocytogenes was immediately reduced during ripening period (during 15 days) in sucuks produced from both controlled and traditional methods. The reduction in the number of L. monocytogenes was also continued during storage periods (15 days). There was no survival of L. monocytogenes after 25 days (10 days storage) in sucuks contaminated with low level of L. monocytogenes ripened in both methods. AB, LAB and MY were also reduced during ripening and storage periods. Parameters of non-linear modified-Gompertz and logistic models of L. monocytogenes, AB, LAB and YM in sucuks ripened in controlled and traditional methods were matched in a satisfactory way during ripening and storage periods. Both the modified-Gompertz and logistic models showed good fit to all the survival curves as assessed using the root mean square error (RMSE) and the correlation coefficient ( R 2) between the experimental and predicted values but the modified-Gompertz model best fit ( R 2 ≥ 0.98) than the logistic model ( R 2 ≥ 0.96). As a consequence, the model provides parameters for different production methods in modified-Gompertz model against microorganisms.