A person becomes infected with E. coli 0157:H7 by swallowing the bacteria. This can
occur when an individual eats food which has become contaminated with E. coli
0157:H7, most frequently undercooked ground beef and raw milk. Transmission also
can occur directly from person-to-person in families, child care centers and custodial
institutions. Outbreaks have also been traced to contaminated water.