Integrating kinetic models and BP-ANN for predicting growth and shelf-life of Listeria monocytogenes in ready-to-eat salads
Wenqian Li, Qiongmin Wang, Zichen Deng, Yan Du, Yihuan Song, Tianyu Xu, Shan Lei, Jingyu Chen
Abstract
Ready-to-eat (RTE) salads are popular for their convenience and health benefits. However, their reliance on refrigeration increases the risk of contamination by Listeria monocytogenes . In this study, vegetable salads (VS) and salads with 10% (10S), 20% (20S), and 30% (30S) chicken breast were inoculated with a L. monocytogenes cocktail and stored at 4, 10, or 15°C for 14 days. The results indicated that higher storage temperatures and longer durations significantly increased microbial activity. A positive relationship was observed between chicken breast content and total viable count (TVC) as well as L. monocytogenes growth. At the end of storage, the TVC in 30S was 8.57 ± 1.39 log CFU/g higher than that in VS. As determined by the logistic model, the highest maximum growth rate ( μ max ) observed in 30S at 15°C was 0.0589 ± 0.0004 log CFU·g -1 ·h -1 . Salads with meat had a shelf life of up to 9 days, while the increase in L. monocytogenes in VS remained below 3.4 log CFU/g throughout the storage. Furthermore, the equation μ max-30S = {0.0059 × (T + 25.9983)} 2 was used to indirectly optimize shelf-life assessments for retail salads and provide reliable estimations (R 2 = 0.9951). The study successfully incorporated the back-propagation artificial neural network (BP-ANN) to validate the accuracy of traditional kinetic models in predicting the μ max of L. monocytogenes . An R 2 greater than 0.97 was achieved across all training data. These findings offer invaluable insights for optimizing storage practices and improving food safety risk assessments for RTE salads. • The growth dynamics of L. monocytogenes and TVC in RTE salads were investigated. • μ max of L. monocytogenes was affected by meat content and storage temperature. • Storage at 15°C notably affected the μ max of L. monocytogenes in meat-rich salads. • Square root model and BP-ANN were used to predict the shelf life of retail salads. • BP-ANN confirmed logistic model applicability and improved multi-variable analyses.