Milk is a highly nutritious, but is a perishable food containing protein, fat and sugar. The milk sold today is pasteurized, meaning the milk is heated for a brief period of time to kill disease-causing bacteria; however, this process does not kill ALL bacteria. The sugar present in milk (lactose) allows bacteria to grow and multiply which will lead to spoiling. Keeping milk continuously refrigerated and sealing the container well after each use will help to keep milk fresh for up to a week past the sell-by date on the package.
A small sip of spoiled milk is unlikely to cause symptoms beyond a bad taste. Drinking larger amounts of spoiled milk can cause stomach distress resulting in abdominal cramping, vomiting and diarrhea (like a food-borne illness). In most cases, symptoms caused by drinking spoiled milk resolve within 12-24 hours. The key is to prevent dehydration by sipping small amounts of fluid that contain sugar or electrolytes, such as popsicles and oral rehydration fluids (Pedialyte® for children). Avoid taking any medication to stop diarrhea because anti-diarrheal medications decrease the elimination of whatever caused the problem.
If you or your child has ingested spoiled milk, do not panic. Rinse the mouth thoroughly and give them some water to drink. If problems start or you have questions, call the Missouri Poison Center right away at 1-800-222-1222. The poison center is open all day, every day for poisoning emergencies and questions.