"The problem occurs when people don't cook the meat correctly, but it also occurs in the handling," said Sandra Bastin, associate professor of food and nutrition at the University of Kentucky.
To ensure that bacteria are killed during cooking, the meat's internal temperature needs to reach at least 160 degrees, according to the CDC. Depend on a thermometer, rather than color, to judge if a piece of meat is cooked properly, Bastin said.
Meticulous prep work can help avoid spreading food-borne illnesses. It is important to wash hands thoroughly before and after handling meat. Any surface in contact with raw meat should be kept separate from other foods and washed. And keeping raw meat cold until cooking time can prevent more bacteria from growing. Bastin recommended buying refrigerated or frozen meats last at the grocery store.
It may be true that "dirt don't hurt," but the parasites lurking in it may.
Whether it's the shore of a lake, the beach, a sandbox or some soil in the summertime, experts say it's worth following some hygienic rules.
Parasitologist Susan Wade said the occasional terrestrial parasite can make us sick, including the Toxocara canis and Toxocara cati -- essentially worms from cat and dog droppings.
"If they defecate and the eggs are in the sandbox, they take about a month to mature," said Wade, director of the parasitology section of the animal health diagnostic center at Cornell University in Ithaca, N.Y.
"If kids are playing in the sandbox and put their fingers in their mouths, they can get infected," Wade said. "It could be more than sandboxes, they could defecate any place kids might be playing in the dirt."
Raccoons can make summer fun in the dirt dangerous, too. According to Wade, they can spread the much more serious Baylisascaris procyonis parasite.
Luckily, the advice to stay safe is simple.
"Wash your hands after you've been playing in the dirt," said Wade, especially if it's in a place with lots of dogs or cats around.
The family cat and dog might seem safer (and cuter) to touch, but bacteriologist Craig Altier of Cornell says the frogs and toads you find outside could carry less disease.
Altier said that when it comes to bacteria, the biggest concern from local animals and pets on the ground might be salmonella, commonly carried by reptiles.
"Salmonella in reptiles is much more common in caged reptiles than in wild animals," said Altier, who is an associate professor of microbiology at the university's College of Veterinary Medicine. "I wouldn't freak out when my kids bring home toads and frogs."
For people who fear swimming in the great outdoors, a simple trick might be to look around at whose swimming near you.
"There are only a certain number of microorganisms that get transmitted from animals to humans," said Saul Tzipori, professor of microbiology-infectious disease at the Cummings School of Veterinary Medicine at Tufts University, in North Grafton, Mass.
Tzipori said E. coli might top the list in terms of serious infections, but there are others, all transferred from fecal matter in the water to our stomachs.
"If you are in a river or in a lake that's contaminated from other humans or animals, that's how you catch E. coli," he said.