Using consumer acceptance to guide microbial thresholds for the shelf life of fresh chicken breasts.

A declared shelf life aligned with consumer acceptance is essential to avoid unnecessary food waste. The relationship between microbial development and consumers' odour-based decisions to accept or discard industrially packed chicken breasts from three European countries (Hungary, Norway and Portugal) was investigated. Products were stored at 4 °C up to 27 days, with or without a shift to 8 °C after 3-7 days to mimic temperature abuse at retail/consumer stages. Bacterial levels were quantified by culture-based enumeration (total viable counts, TVC), and the microbiota assessed by 16S rRNA gene amplicon sequencing. In each country ≥120 consumers assessed acceptance based on odour. Acceptance was modelled through survival analysis using time (days) and TVC as predictors. Initial TVC differed among products (2.5 - 4.3 log cfu/g). Dominant taxa were Photobacterium (Hungary), Lactobacillales (Norway), and Brochothrix together with Yersiniaceae (Portugal) at the end of the declared shelf life. Temperature abuse shifted the microbiota towards higher proportions of Enterobacterales (Norway and Portugal). Sensory shelf life varied markedly, with 25% rejection rates reached after 9 days (Hungary), 25 days (Norway), and 12 days (Portugal) during storage at 4 °C, corresponding to TVCs of 6.4, 7.4 and 7.3 log cfu/g. We propose a consumer-anchored methodological approach for shelf life assessment that (i) predefines an acceptable rejection level (ii) models acceptance as a function of TVC under foreseeable abuse and (iii) complements culture-dependent analyses with culture-independent profiling. This approach links microbial criteria to consumer perception and behaviour and providing a basis for more accurate, consumer-anchored shelf-life determination.