Time-temperature profiling of UK consumers’ domestic refrigerators

Abstract

Increased consumer demand for convenience and ready-to-eat (RTE) food, along with changes to consumer food purchase and storage practices have resulted in an increased reliance on refrigeration to maximize food safety. Previous research suggests that many domestic refrigerators operate at temperatures exceeding recommendations, however several studies are determined by means of one temperature data point, which, given temperature fluctuation, may not be a true indicator of actual continual operating temperature. Data detailing actual operating temperature and the impact of consumer practice on temperature are limited. This study has collated the time-temperature profiles of domestic refrigerators in consumer kitchens (n=43) over 6.5 days with concurrent self-report refrigerator usage. Overall, findings established a significant difference (p<0.05) between one-off temperature and mean operating temperature. No refrigerator operated at ≤5.0°C for the entire duration of the study. Mean temperatures exceeding 5.0°C were recorded in the majority (91%) of refrigerators. No significant associations or differences were determined between temperature profiles and demographics including household size and refrigerator characteristics (age, type, loading and location). A positive correlation (p<0.05) between room temperature and refrigerator temperature was determined. Reported door opening frequency correlated with temperature fluctuation (p<0.05). Thermometer usage was determined to be infrequent. Cumulatively, research findings have established that the majority of domestic refrigerators in consumer homes operated at potentially unsafe temperatures influenced by consumer usage. Findings from this study may be utilized to inform the development of shelf-life testing based on realistic domestic storage conditions. Furthermore, data can inform development of future educational interventions to increase safe domestic refrigeration practices.