Bad cheese can include Salmonella, Listeria, E. coli, and Brucella, and consuming such cheese can result in a variety of foodborne diseases, most notably food poisoning, which is characterized by nausea, vomiting, diarrhea, abdominal cramps, and fever. In severe cases, malnutrition can result from eating bad cheese. Food poisoning occurs when the bacteria that cause some foods to spoil reach the stomach intact and can grow there. The most common causes of food poisoning are undercooked meat, fish, and poultry; unsafe food handlers; and eating out without knowing what kind of cooking process has been used for the food. Food poisoning can also be caused by drinking contaminated water or milk products (such as yogurt) containing the bacteria Streptococcus pyogenes. Some cheeses, such as Brie and Camembert, are made with bacteria that can cause serious illnesses for people who are allergic to those bacteria. People who are allergic to sulfites, another type of preservative, should not eat any cheese because many types of cheese contain sulfites. Cheese has been a part of human culture since prehistoric times, when people first started making it. Although cheese making technology has improved over time, the process remains difficult and labor-intensive. A dairy farm needs enough cows to produce more than they can consume so that some of their milk goes to waste.