If you’re a fan of apples, then you’re a fan of apple cider. And there’s no better drink to summarize fall (well, other than a pumpkin spice latte, I guess) than apple cider. However, health officials are warning about the risks that come with drinking the beloved autumn beverage.

Unlike apple juice, apple cider is unfiltered and sometimes unpasteurized. That means bacteria from the apples or other sources can sometimes find its way into the raw juice, according to the U.S. Food and Drug Administration.

Pasteurization is a process that uses heat to kill any bacteria that may end up in the apple cider, but it’s not required by the FDA if the cider is being sold directly to a consumer by the glass or made, packaged, and sold onsite. If the unpasteurized apple cider is packaged (rather than sold by the glass), it has to be refrigerated and have a label warning to consumers that it’s not pasteurized.

For example, the Ogle County Health Department in Illinois issued a seasonal health advisory to warn people about the dangers of unpasteurized apple cider on its Facebook page.

“Apple cider is a beverage made from fresh apples. It is typically a bit murky and golden-colored because it’s unfiltered and unpasteurized,” the department sad. “Most apple orchards don’t’ take the time to pasteurize because it is not required.”

The main concerns that come with drinking apple cider include:

  1. E. coli contamination: Apples that fall to the ground and come in contact with animal feces can be contaminated with E. coli bacteria. When these apples are pressed into cider without pasteurization, the bacteria can survive in the juice.
  2. Other pathogens: Besides E. coli, unpasteurized cider may contain other harmful microorganisms like Salmonella or Cryptosporidium.
  3. Lack of kill step: Pasteurization heats the juice to kill harmful bacteria. Without this process, any contaminants present remain in the cider.

Symptoms of foodborne illness from contaminated cider can include stomach cramps, diarrhea, vomiting, and even fever. The risks for this type of illness are particularly high for young children, pregnant women, older adults, and people with weakened immune systems.

Experts recommend only consuming pasteurized apple cider, keeping it refrigerated, and checking for pasteurization labels.