Bacteria grows rapidly at warm temperatures, so at the picnic's end, throw out perishables such as luncheon meats, potato or pasta salad and meat or poultry. Smith says others bring desserts like squares and cookies. And with such a large number of participants, food safety is very much an issue. Remember, she says, it has to be 100 per cent cold when it goes into the cooler. Smith says a lot of people make the error of thinking that it's the mayonnaise in a potato salad that makes it unsafe to eat.
Commercial mayonnaise has enough acid in it to withstand any contamination.
But potatoes must be cool, not warm when they are mixed with other ingredients and then kept in the coldest part of the fridge before packing into the cooler. It has to be the right temperature before going in. To keep the crispness of a green salad, toss it with the dressing at the picnic site. Transport the dressing in a screw-top jar packed in the same container as the salad. To ensure that you remember to take a corkscrew and to make it easy to find at the picnic site, tape it to a bottle of wine using masking tape.