Occurrence and Effects of High Temperatures on Rations Stored in Container Vansat Yuma, AZ, 1992-1995

摘要

Three container vans (CVs) used to transport and store rations in OperationDesert Shield/Storm (ODS) in 1991 were relocated at the Yuma Proving Ground Yuma, AZ to monitor heat stress occurring in military rations in a desert climate. One of the vans contained Meal-Ready-To-Eat (MRE) Rations one B Rations and one contained Tray Rations. A total of 64 thermocouples were attached throughout the vans and temperatures were recorded hourly. Time-temperature indicators (TTI) were also attached to some cartons and sample MREs inserted for sensory and objective evaluation after storage. Temperatures were analyzed for the period 18 June 1992 to 31 December 1995. Results show that despite the small headspace in the CVs, the maximum temperatures in the most critical top ration cases rarely exceeded 120 deg F (49 deg C), although temperatures four inches below the roof reached 151 deg F (66 deg C). Rations stored for the summer six months in the vans experienced about the same heat stress similar rations stored at a constant temperature of 100 deg F. Temperature dependence of sensory and objective degradation of rations stored in the vans was consistent with an Arrhenius activation energy of 26 kcal/mole. Effective mean constant temperatures computed to represent the degradation caused by the varying van storage temperatures in 1995 were 93 deg F for the year, 100 deg F for the hottest summer six months, 106 deg F for the hottest three months, and 108 deg F for the hottest month. For periods of less than one year, the seasonal effects are extreme, the hottest summer month experiencing about 40 times the degradation rate of the coldest winter month.