[originaltext] During the summer you should be even more careful than usual

During the summer you should be even more careful than usual of the food you prepare. Food spoils faster in hot weather than in cold weather. When you are shopping, purchase frozen and refrigerated foods at last. Don’t make long stops on the way home, because frozen foods could become soft or warm. Using insulated bags helps keep food cold until you can get home. Milk and milk products should be refrigerated immediately. When camping or picnicking, or at any time when refrigeration isn’t available, use special dry food. Don’t leave foods in a hot car or beach bag. Picnic favorites like meat, chicken, and egg salad should be kept in a cooler. Above all, if a food doesn’t seem to be normal in odor or appearance, discard it immediately. Don’t taste it.
16. Why should we be more careful than usual when we prepare the food in summer?
17. Which of the following foods would be least likely to spoil in warm weather?
18. According to the passage, what should we do with food that doesn’t seem to be normal?