Development of a new mathematical model for inactivation of Escherichia coli O157:H7 and Staphylococcus aureus by high hydrostatic pressure in carrot juice and peptone water

2009-02-01
PILAVTEPE-CELIK, Mutlu
BUZRUL, Sencer
Alpas, Hami
BOZOGLU, Faruk
Survival data of Escherichia coli O157:H7 933 and Staphylococcus aureus 485 in carrot juice and peptone water were collected in a range of pressure levels between 200 and 400 MPa at 40 degrees C. A mathematical approach combining the primary and secondary models (Weibull and first-order models as the primary model and two empirical equations as the secondary model) was proposed to estimate the microbial parameters using nonlinear least squares procedure in one step, resulting a single equation. Although not perfectly matched with the survival data, the proposed model produced good fits. Better fits were observed for S. aureus than for E call. Simulations of 5log(10) reductions of both pathogens indicated that carrot juice had a protective effect on E. coli whereas it had a sensitizing effect on S. aureus. The development of such mathematical models would be very beneficial to the food industry by developing safe processing conditions for HHP processing of foods.