Most patients have become ill since mid-October, Lola Russell, a spokeswoman for the federal Centers for Disease Control and Prevention in Atlanta, said. She said the outbreak was still growing and DNA testing implicates a common strain known as salmonella typhimurium, The Wall Street Journal reported.

The typhimurium strain is commonly found in poultry, produce, raw milk, cheese, or spread through contacts with animals such as small turtles, Russell said.

Salmonella, a major food safely problem in recent years, is a feces-borne bacterium that can cause diarrhea, fever and severe cramps.