Effect of cold chain interruptions on the shelf-life of fluid pasteurised skim milk at the consumer stage

Abstract This study aimed to verify the effect of time and temperature abuse on bacterial numbers in fluid pasteurized skim milk by simulating the real-life scenario, which usually occurs when cold chain is interrupted by consumers prior to consumption that affect the shelf-life of milk. Total three trials were carried out in this study. Thermal abuse was simulated with temperature fluctuations from 5 °C. In the first trial, the information about holding the milk samples for 8 hours at three different temperatures of 15 °C, 20 °C and 25 °C was obtained using a data logger to predict the effect of temperature abuse on the milk microbial quality. Further, in the second and third trial, the effect of temperature abuse on bacterial numbers was examined by holding milk at 5 °C and then shifts temperature to 25 °C for 8 h and 6 h. The pH was monitored during storage. The total bacterial count was examined by the Standard Plate Count (SPC). The mean air temperature had the greatest impact on milk temperature. It took 3.0 h, 3.9 h and 4.2 h to warm up when exposed to the temperatures of 15 °C, 20 °C and 25 °C, respectively. The holding time of 8 h at 25 °C showed that bacterial numbers (1 x 105 CFU mL-1) were higher after 14 days of storage, but control samples at 5 °C (