Determining effects of temperature abuse timing on shelf life of RTE baby spinach through microbial growth models and its association with sensory quality

Abstract Maintaining cold chain integrity during postharvest handling is of paramount importance to ensure the quality and shelf life of ready-to-eat (RTE) fresh-cut produce. However, breaks in cold chain may occur due to supply logistical issues and system failures. This study evaluated the effect of temperature abuse encountered i) immediately after processing and ii) in a late stage of shelf life on microbial growth and on related quality attributes of RTE baby spinach. Baby spinach samples, maintained at 1 °C and transported to the research facility via a refrigerated truck within 2 d of commercial production, were divided into two groups. The first group was immediately transferred to refrigerated rooms maintained at 1, 4, 8, 12, 16, and 20 °C while the second group was transferred to the same storage temperatures after 6 d of storage at 1 °C. Total aerobic bacteria, psychrotrophic bacteria, and yeast and mold counts indicated that all tested microorganisms grew slowly when held consistently at 4 °C, but more rapidly when stored at 8 °C and above. The effect of temperature abuse on microbial growth was described by a no-lag phase (primary) model and a suboptimal Huang square-root (secondary) model, which were validated and therefore can be used to predict the microbial growth in baby spinach with a reasonable accuracy. Indigenous microbial populations were highly associated with sensory attributes, with a negative correlation between aerobic plate acount and overall quality. The results of this study accentuate the importance of cold chain maintenance during the distribution of RTE baby spinach and the potential application of predictive modeling for estimating shelf-life. Such models can help the industry make science-based decisions to improve safety and quality of fresh produce. It can also serve as the basis for future artificial intelligence research to optimize the shelf life of RTE produce.