Some foods last longer than others. A whole roast will keep for up to a week in the refrigerator, while ground beef must be used within a day or two. Meats should be removed from the store packages and rewrapped as soon as you get them home. If you want to freeze hamburger, form it into patties and use plastic coffee can lids to separate them. Wrap the whole stack in plastic and freeze. Berries will often turn to mush if you just put them in the freezer. Instead, spread them out on a cookie sheet to freeze, then transfer them to plastic bags. In the refrigerator, tomatoes will stay fresh longer if you set them stem-side down. Cottage cheese is also best stored upside-down in the refrigerator. To keep bread fresh longer, put a rib of celery in the bag. Lettuce and celery stay fresh longer in paper bags than in plastic. A pinch of salt in a gallon of milk will keep it fresh past its expiration date. You can sometimes even bring foods that are past their prime back to life. Limp lettuce and celery may become crisp again if you soak them in ice water with a few drops of vinegar for an hour or so.