Apple cider is a fall favorite, but in some cases it can make you sick if you're not careful. Local health department are warning consumers to take notice if their cider is unpasteurized because of the risk of potential foodborne illness.

Apple cider, made from fresh apples, "is typically a bit murky and golden-colored because its unfiltered and unpasteurized. Most apple orchards don't take the time to pasteurize because it is not required," Illinois's Ogle County Health Department shared on social media. "Apple cider that has NOT been pasteurized can contain harmful bacteria that can make people sick."

The Fulton County Health Department in Georgia shared similar messaging. "Make sure to check labels this fall -- it's required to disclaim if the product has been heat treated or not," the department wrote, adding that if you do purchase unpasteurized cider from an orchard, the Centers for Disease Control and Prevention recommends boiling it for at least 1 minute before drinking.

While most juice sold in the United States is pasteurized or heat-treated to kill harmful bacteria, according to the U.S. Food and Drug Administration, untreated juices or ciders can pop up, including at some grocery stores, health food stores, cider mills, farmers' markets and juice bars.

These packaged products are required to have the following message on the label: "WARNING: This product has not been pasteurized and therefore may contain harmful bacteria that can cause serious illness in children, the elderly, and persons with weakened immune systems."

But this label is not required for juice or cider sold by the glass, which is common at apple orchards, farmers' markets, roadside stands, juice bars and some restaurants, the FDA notes.

That's why the FDA urges consumers to look at labels and ask if they are unsure.

"Don't hesitate to ask if the labeling is unclear or if the juice or cider is sold by the glass," the agency's website states.

Those most at risk for serious illnesses or even death from drinking unpasteurized juices (or unpasteurized raw milk) include children, older adults age 65+, pregnant women and people with weakened immune systems.