The temperatures and ages of packs of beef displayed in multi-shelf retail cabinets

The temperatures and ages of 5389 packs of beef in 10 multiple shelf display cabinets were determined. The median temperature of the packs in each cabinet was <4 °C. The maximum temperatures of the packs in six cabinets were >7 °C. All packs in three cabinets were ⩽2 days old. The percentages of packs older than 2 days were <1% in three cabinets, about 40% in three cabinets and about 70% in one cabinet. Both aggregated data and data for individual cabinets indicated that, generally, older packs were cooler than newer, packs at the backs of shelves were cooler than packs at the fronts, and packs on intermediate shelves were cooler than packs on bottom or top shelves. The aggregated data also indicated that the temperatures of packs did not differ at different times of the day, or at different positions along cabinets; and that packs in lower layers were generally cooler than packs in top layers. However, the findings for individual cabinets were that packs in nine cabinets had different median temperatures at different times of the day, that temperature gradients existed along five cabinets; and that temperatures of packs in different layers did not differ. Consideration of only aggregated data from surveys may lead to some erroneous conclusions about display cabinet performances.