Non-invasive detection of cold chain disruptions in modified-atmosphere packaged minced pork using a handheld fluorescence device

This study demonstrates the suitability of a handheld fluorescence device for the detection of cold chain disruptions (CCDs) of modified-atmosphere packaged minced pork through the package or with unpacked samples. Fluorescence spectra of minced pork stored at a constant temperature of 2 °C were highly correlated with the storage time after processing of the meat. Partial least squares regression (PLSR) models for spectra recorded through the package or for unpacked samples yielded cross-validated R2CV = 0.90 or 0.95, respectively. Validation with independent samples investigated under controlled conditions resulted in R2Pred = 0.83 for measurements through the package and 0.88 for measurements of unpacked samples. Unlike the controls, minced pork, which underwent a CCD at 14 °C on storage day 2, was systematically predicted older than its actual storage time depending on the duration of the disruption: 1.1–1.7 d older after a 6-h disruption and with 2.5–3.5 d significantly older after a 12-h disruption. In contrast, CCD-dependent changes of total viable counts (TVC) only appeared on tendency after a 12-h CCD and PLSR predictions of TVC performed inadequately. The storage-time effect detected by fluorescence spectroscopy was apparent already one day after the disruption. The results indicate that fluorescence spectra monitor an ageing process of meat, which is accelerated by a temporarily elevated storage temperature. The comparison of predicted and actual storage time could be useful for a rapid, non-invasive detection of cold chain disruptions and for an assessment of time and temperature effects on the shelf life.