Modeling the Effect of Marination and Temperature on Salmonella Inactivation during Drying of Beef Jerky

Abstract

This study modeled the effect of drying temperature in combination with predrying marination treatments to inactivate Salmonella on beef jerky. Beef inside round slices were inoculated with Salmonella and treated with (1) nothing (C), (2) traditional marinade (M), or (3) dipped into a 5% acetic acid solution for 10 min before exposure to M (AM). After 24 h of marination at 4 degrees C, samples were dehydrated at 52, 57, or 63 degrees C. Total counts (tryptic soy agar supplemented with 0.1% sodium pyruvate, TSAP) and Salmonella (XLD agar) were enumerated after inoculation and at 0, 2, 4, 6, 8, and 10 h during drying. For calculation of death rates (DR, log CFU/cm(2)/h), shoulder period (h), low asymptote, and upper asymptote, cell counts from TSAP were fitted to the Baranyi model. The DRs were then further expressed as a function of storage temperature. Inactivation occurred without an initial lag phase (shoulder period), while correlation (R(2)) values of fitted curves were >/= 0.861. The DRs of C (-0.29 to -0.62) and M (-0.36 to -0.63) treatments were similar, while DRs of the AM treatment were higher (-1.22 to -1.46). The DRs were then fitted to a polynomial equation as a function of temperature. After validation, good (C and M) or acceptable (AM) model performances were observed (R(2)= 0.954 to 0.987; bias factors: 1.03 [C], 1.01 [M], 0.71 [AM]; accuracy factors: 1.05 [C], 1.06 [M], 1.41 [AM]). The developed models may be useful in selecting drying temperatures and times in combination with predrying treatments for adequate inactivation of Salmonella in beef jerky.