calves, and other animals, but has little if any
effect on them. Ground beef is by far the most
common source of E. coli O157:H7 infection.
Grinding mixes and spreads what may be only
a small contaminated portion throughout the
entire mass of meat.
Prevention Prevention of bacterial infection
begins with the well warranted assumption
that all meat has been contaminated with at
least some disease bacteria. It requires
measures to ensure that those bacteria are not
spread to other foods, and are eliminated from
the meats during cooking. Hands, knives,
cutting boards, and countertops used to
prepare meats should be cleaned with hot
soapy water before being used to prepare
other foods. E. coli are killed at 155ºF/68ºC,
so ground meats are safest if their center gets
at least this hot. Salmonella and other bacteria
can multiply at significant rates between 40
and 140ºF/5–60ºC, so meats should not be left