"In the food safety realm, we say, 'don't eat crap,'" said Douglas Powell, a Kansas State University professor of food safety. "However, if you're going to do it, make sure it's cooked." Proteins were extracted from bacteria in sewage by Japanese researchers. The proteins were used to make food additives. The results were published last year in the journal Applied and Environmental Microbiology. The study found that proteins derived from bacteria in sewage were similar to those found in milk and meat products and could be used instead of real milk or eggs in foods such as cookies and cakes. The researchers also suggested that the proteins could be used to make medicine or vaccines. People have been eating feces for centuries as part of various religious rituals or because they had no choice because they were starving. In more recent years, scientists have also started using feces as a source of nutrients for lab experiments. Feces contain many useful things our bodies need, such as vitamins, minerals, and bacteria that help control infections. The main problem with eating feces is the presence of viruses that can be passed on to others through contact with the contaminated food handler's skin. These viruses include HIV, hepatitis B virus, and syphilis. Scientists in Japan figured out how to extract protein from bacteria in sewage and use them in food products.