Before handling food, we should wash our hands and use clean utensils, not allowing food to come into contact with any surface not previously sanitized.
Change the utensils for every type of aliment or for the previously cooked and not cooked, this way we avoid the cross contamination.
The cold consumed dinners, must be putted in a clean recipient, hermetically close and fridge conserved. Take it of the fridge right before we go out home. Fridge it again when arrive to school; if there’s no possibility to do that, we have to make sure our selves that the ice keeper.
Exclude the use of egg in the meals, specially the not cooked kind (without termic tratement), like in mayonnaise sauces. It’s better to prepare, for example, a salad and dress at the moment of eat it including the commercial mayonnaise.
In the case of hot meals: it has to be cold about an hour a go (never freeze it while it’s hot.) Close hermetically and freeze.
Choose always the hygienic and stable products: like mature cheeses instead of fresh cheeses, dairy or industrial desserts instead of homemade ones, better a steak than a tortilla…
Do not eat meals made with more than 48 hours in advance or if we have any doubt about their status.
Never reuse or freeze the possibly rests of homemade food consumed outside of our home.