‘Tis the season for gathering with friends and family and eating. Whether you celebrate Christmas, Hanukkah, Kwanzaa or Festivus for the rest of us, many of us invite people to our homes during the holidays and leave food out to graze. Leaving food out for more than two hours can be hazardous to your health and that of your guests, caution UC Cooperative Extension nutrition experts.

You may be thinking, “My family has eaten food that has been sitting on the table longer than two hours and survived.” Consider yourself lucky.

“We keep learning more about foodborne illness,” says Patti Wooten Swanson, UC...