A University of Texas study found that 90 percent of bag lunches brought to school by preschool students were kept at temperatures that could result in food-borne illnesses.
The researchers took the temperatures of 700 preschoolers lunch's at nine different Texas child care centers. Forty-five percent of the lunches had at least one ice pack and 39 percent had none.
While ice packs are recommended, they didn't always solve the problem. Eighty-eight percent of lunches, including those with ice packs, were at room temperature when measured. Only 2 percent of lunches with perishable items (such as meats, cheeses and vegetables) were at safe temperatures. When these items get too hot they can harbor bacteria growth that can cause illness.
According to the study, cold foods should be kept below 40 degrees. Hot foods should be kept above 140 degrees. The lunches should never be between those temperatures.
The study said that in many cases the lunches were just one ice pack short of safe temperatures. Researchers also said that two or more ice packs in lunches could help prevent food-borne illness in children.
The study omitted prepackaged foods.