Predictive assessment of microbial growth in refrigerated food using Accelerated Shelf-Life Testing

Lactic acid bacteria (LAB) are known to spoil the processed meat products; hence, assessing post-sterilization cross-contamination is essential for maintaining product quality. Notably, LAB growth is often observed during refrigeration, even when the initial bacterial count is below the detection limit. This highlights the need for a reliable approach to predict the LAB populations at the end of the shelf-life to support hygiene management. In the present study, we developed an Accelerated Shelf-Life Testing (ASLT)-based model for assessing the acceptability (threshold: 5.0 log₁₀ CFU/mL) of LAB populations at the end of the refrigerated shelf-life. The proposed model was constructed based on the growth kinetics of Lactococcus piscium 105 in broth media. The model demonstrated, for instance, that for a 30-day refrigerated shelf-life, an ASLT standard value is 2.07 log₁₀ CFU/mL (or CFU/g). This suggests that if the LAB populations in a processed meat product increase to ≥2.07 log₁₀ CFU/g in ASLT, it is predicted to exceed the acceptable limit at the end of the 30-day refrigerated shelf-life. The relationship between the ASLT standard values and shelf-life durations was described by a power function. Furthermore, the model was successfully validated for actual processed meats, as evidenced by R² and RMSE values of 0.948 and 0.467, respectively. The proposed model provides a novel framework for the early assessment of the risk of LAB growth under refrigeration and is expected to support rigorous hygiene management.