Abstract:The predictive shelf life model for pork patties affected by specific spoilage bacteria (SSB) was established. The SSB were inoculated into the ozone-treated pork patties, vacuum packaged and stored at -1, 4, 10, 15 and 22 ℃ (temperature fluctuation ±1 ℃). The total volatile base nitrogen (TVB-N), pH and thiobarbituric acid resctive subastances (TBARS) values, the total viable count (TVC), and the sensory scores of the patties were determined during the storage period (0~11 d). Using the modified Gompertz equation and square root model (Bĕlehrádek), a microbial shelf life model of the patties with SSB as the key quality factors was established. The results showed that the modified Gompertz equation seemed to fit better the growth curves of SSB under different storage temperatures, while the square root model (Bĕlehrádek) described the effects of temperature on the maximum specific growth rate (μmax) and the lag phase (Lag). Both of which showed good linearity (R2 as 0.98 and 0.83, respectively). The average logarithmic value of minimum SSB for the pork patties stored at -1, 4, 10, 15 or 22 ℃ was (6.94±0.21) lg (cfu/g), and the average value of lgNmax was (8.65±0.16) lg(cfu/g). Accordingly, the model for patties stored at -1 ℃~22 ℃ was established. The prediction model was validated based on the measured shelf life at 10℃ and 15℃, and the relative error was less than 10%, indicating that the model based on the square root equation was effective for predicting the shelf-life of SSB in pork patties stored at -1 ℃~22 ℃.
