MONDAY, Aug. 8, 2011 (HealthDay News) -- Despite parents' best intentions, many school lunches packed at home may reach unsafe temperatures by the time a child eats, and that's true even when lunches are packed in an insulated container with ice packs.
A new study of preschoolers' lunches found that more than 90 percent of the food sent from home was at an unsafe temperature long before children started eating.
"The main finding of our study is that more than 90 percent of perishable items were at an unacceptable temperature -- according to USDA guidelines -- an hour and a half before lunch," said study author Fawaz Almansour, a doctoral candidate in the department of nutritional sciences at the University of Texas at Austin.
"This was an eye opener. As a parent, when my child comes home with a stomachache or vomiting, I usually think it's a virus. I don't think the food I serve is the problem," he said.
But, foodborne pathogens may actually be the cause. When kept at improper temperatures, bacteria can multiply rapidly, which makes foodborne illness more likely. And, the study authors pointed out that food-borne illness is a particular risk for youngsters under the age of 5 years.
Results of the study will be published online Aug. 8, and will appear in the September issue of Pediatrics.
The study included nine central Texas day care centers that care for children between the ages of 3 and 5. Most of the parents were married, and almost 90 percent of the parents had at least some post-secondary education, according to the study. Seventy percent of the families were white, 12 percent were Asian, 9 percent were Hispanic and 3 percent were black. Sixty percent of the parents were between 30 and 39 years old.
The researchers tested the temperature of individual perishable items from 705 lunches. They tested the foods 1.5 hours before the kids' scheduled lunch time because children are often allowed to start snacking on their food prior to lunch.
About 39 percent of the lunches had no ice packs, while 45 percent had just one ice pack.
Most of the lunches -- more than 88 percent -- were at room temperature, according to the study. Just 1.6 percent of perishable items were kept in the safe temperature zone recommended by the USDA. The USDA recommends that cold food be kept at less than 40 degrees Fahrenheit, and that no food should be at room temperature for more than two hours.
The study found that even when multiple ice packs were used, food often wasn't at a safe temperature.
In addition, refrigerators didn't help significantly in keeping foods at the proper temperatures. This may be because foods were left in insulated containers and placed in the refrigerators, allowing the container to actually insulate the food from the refrigerator.
Also, refrigerators weren't always kept at the proper temperature (below 40 degrees F), were sometimes overcrowded, and kids often opened the refrigerator doors, sometimes leaving them open for awhile.
"The vast majority of lunches were clearly out of a safe range, but it's hard to know what the true biological impact of that is. We don't truly know how often this results in a foodborne illness," said Dr. Michael Green, a pediatric infectious disease specialist at Children's Hospital of Pittsburgh. "This paper raises a lot of questions, but isn't able to provide a lot of solutions."
He suggested that parents could pack food for their children that isn't so dependent on being kept at a proper temperature, like fruit or peanut butter.
But, Almansour said that kids' nutrition might suffer if parents avoided perishable foods. One possible solution might be to put the lunch in a paper bag, and transport it to the day care center in an insulated cooler, but remove the paper bag from the container and place it in the refrigerator once at the day care.
Learn more about packing safer school lunches from FoodSafety.gov.