Answered by Linda Liu on Thursday, May 28, 2009
"Acidic foods like lemon juice and orange juice are generally not food-safety problems because their low pH prevents the growth of most bacteria," says Joan Carter, R.D., senior nutrition communications specialist at the USDA/Agricultural Research Service Children's Nutrition Research Center at Baylor College of Medicine. "But care still needs to be taken when choosing storage containers." Generally, problems occur when a high-acid food or juice is stored for a period of time in metallic containers that have damaged protective coatings or are not meant for food. These problems can include zinc poisoning from galvanized buckets; antimony poisoning from chipped enamelware; lead poisoning from decorative or poorly glazed stoneware made with iron-containing clays; and copper poisoning from decorative copperware. (Obviously, you don't want to cook acidic foods in any of these things either.) Although placing aluminum foil on top of acidic foods can cause pitting and food discoloration, the aluminum salt that is created is not dangerous (it can give food a strange taste, however). This is also the problem when acidic food is stored in its original aluminum can—not a safety concern but one that affects flavor and appearance. To avoid problems in storage, Carter suggests keeping high-acid foods in glass containers.