(587c) Fractional Differential Equations Based Modeling Of Microbial Destruction In Meats

Non-linear survival curves of microbial pathogens in meat products were predicted using fractional differential equations. The validity of one and two-term fractional differential equations developed in part?I is performed in this paper using microbial survival and growth data. Experimental inactivation data of Salmonella cocktail in ground turkey breast (0.47% fat, pH 6.04), ground turkey thigh (5.09% fat, pH 6.45) and pork shoulder (17.04% fat, pH 6.36); and cocktail of Salmonella, E.coli and Listeria Monocytogenes in ground beef (16.1% fat, pH 5.85) exposed at isothermal cooking conditions of 50 to 72 ^oC were used for validation. To evaluate the performance of FDE model in predicting the growth curves - growth of Salmonella Typhimurium, Salmonella Enteritidis and background flora in ground pork and boneless pork chops; and E.coli O157:H7 in ground beef at a temperature range of 22.2 to 4.4^oC were chosen. A program was written in Matlab to predict the model parameters, decay and growth curves. Two-term FDE was more successful in describing the complex shapes of microbial survival and growth curves as compared to the linear and Weibull model. Non-linear regression analysis was performed on predictions and high magnitudes of R-square (0.89-0.99) and lower magnitudes of root mean square error (0.0182-0.5461) were obtained in different meat products using the two-term FDE model. This model is capable of predicting the long term tails in survival curves, which is not possible using Weibull and linear models. It can be used for other food-borne pathogens in a variety of food products to study the destruction and growth behavior.