This means that food may be left in an unrefrigerated yet cool environment for a total of four hours. This applies to the time the food is exposed to room temperature when the food is being prepared, which means the amount of time the food actually spends exposed on the truck is two to three hours. When it is time for food to be replaced, backup trucks roll in to pack up the old and bring in the new. Other prepackaged food, such as sushi and tapioca pudding, is supplied by an approved vendor. The name of the vendor and exact ingredients must be displayed on all food packaging materials.
Temperature is one of the most crucial elements in ensuring food safety.
Hot food should be kept above the 140-degree mark, while cold food should never rise above 40 degrees. To ensure safety, then, temperature is strictly regulated in both the hot and cold sections of the trucks. In the meantime, perishable sandwiches and salads are kept cool by a kind of air-conditioning system at the back of the cold shelves. Cooling fans maintain cold foods at safe temperature levels, as indicated by thermometers installed in the truck. These thermometers are tested against the Health District's own thermometers on a regular basis to ensure they are functioning properly.