So, you might want to pick up an extra ice pack or two while you're shopping for your kids' school supplies! Researchers checked the temperatures of lunches sent with children to Texas pre-schools and found that 88 percent of those lunches were at room temperature. That means whatever perishable items were inside were at unsafe temperatures that could lead to foodborne illness.

Results were published online Monday by the American Academy of Pediatrics. Other findings:

  1. 39% (276 of 705) lunches with perishable items had no ice packs.
  2. 45.1% (318 of 705) lunches had one ice pack.
  3. 1.6% (22 of 1361) perishable items in these lunches were found to be at safe temperatures.

The results are specific to pre-schools, but common sense says they could likely be extrapolated to lunches that children take to grade schools, and that adults even take with them to work. Of course, pre-school aged children do appear to be more at risk. The U.S. Centers for Disease Control and Prevention conducted studies in 2009 and found children younger than four have 4.5 times more foodborne bacterial infections than adults ages 20 to 49.

Authors of the study noted it isn't easy, even with ice packs, to keep sack lunches cold enough until lunch time:

I've been guilty of tossing a squeezable yogurt into the my kids' bags at the last moment to try and balance out their lunches. Turns out, there's little chance those dairy products stayed cold. The study examined the temperatures of 582 dairy items packed in pre-school lunches. Temperatures were checked 90 minutes before lunch time. Only six dairy items remained sufficiently cold.

"The simple addition of one extra icepack could have prevented many of the perishable items in lunches from reaching the danger zone," the researchers wrote.