Oh for the love of... HERE:
https://www.cdc.gov/ecoli/general/index.html
That's the "Q&A" page Denise is referring to.
Here's more:
From the Where do STEC infections come from and HOW ARE THEY SPREAD tabs:
STEC live in the guts of ruminant animals, including cattle, goats, sheep, deer, and elk. The major source for human illnesses is cattle. STEC that cause human illness generally do not make animals sick. Other kinds of animals, including pigs and birds, sometimes pick up STEC from the environment and may spread it.
How are these infections spread?
Infections start when you swallow STEC—in other words, when you get tiny (usually invisible) amounts of human or animal feces in your mouth. Unfortunately, this happens more often than we would like to think about. Exposures that result in illness include consumption of contaminated food, consumption of unpasteurized (raw) milk, consumption of water that has not been disinfected, contact with cattle, or contact with the feces of infected people. Some foods are considered to carry such a high risk of infection with
E. coli O157 or another germ that health officials recommend that people avoid them completely. These foods include unpasteurized (raw) milk, unpasteurized apple cider, and soft cheeses made from raw milk. Sometimes the contact is pretty obvious (working with cows at a dairy or changing diapers, for example), but sometimes it is not (like eating an undercooked hamburger or a contaminated piece of lettuce). People have gotten infected by swallowing lake water while swimming, touching the environment in petting zoos and other animal exhibits, and by eating food prepared by people who did not wash their hands well after using the toilet. Almost everyone has some risk of infection.
and from the How can they be prevented tab:
- WASH YOUR HANDS thoroughly after using the bathroom or changing diapers and before preparing or eating food. WASH YOUR HANDS after contact with animals or their environments (at farms, petting zoos, fairs, even your own backyard).
- COOK meats thoroughly. Ground beef and meat that has been needle-tenderized should be cooked to a temperature of at least 160°F/70˚C. It’s best to use a thermometer, as color is not a very reliable indicator of “doneness.”
- AVOID raw milk, unpasteurized dairy products, and unpasteurized juices (like fresh apple cider).
- AVOID swallowing water when swimming or playing in lakes, ponds, streams, swimming pools, and backyard “kiddie” pools.
- PREVENT cross contamination in food preparation areas by thoroughly washing hands, counters, cutting boards, and utensils after they touch raw meat. To learn more about how to protect yourself from E. coli, see CDC’s feature, E. coli Infection.
E.Coli doesn't live normally in the human intestinal tract, correct? So unless there was a child AT the Little League game already INFECTED WITH E.COLI who had used the bathroom and not washed their hands before reaching in for the chips, there was really no chance of contracting E.Coli (unless the sandwiches served were contaminated but that wouldn't be the communal bag of chips fault).
ONLY TALKING ABOUT E.COLI TRANSMISSION AND CONTAMINATION.
Not sure why you're doing a pp's work for her, but since it's here and no doubt there are others here who also want to know...
so that one time...when a thread about chips turned into Biology & Infectious Diseases class. 
