With apple season and fall fairs in full swing, Health Canada is reminding people that unpasteurized cider and other fruit juices can sometimes be contaminated with harmful bacteria such as salmonella and E. coli.

These parasites or bacteria can make vulnerable individuals, like children under age five, very ill, and can even lead to death.

Most adults won't get seriously ill from drinking unpasteurized juice products, but certain vulnerable groups face more danger, Health Canada advises. (Matthew Mead/Associated Press)

Pregnant women, older adults and people with a weakened immune system should also avoid drinking unpasteurized products, Health Canada said in a release.

Unpasteurized juice products can be found at some farmers markets, orchards, cider mills, roadside stands and juice bars.

Most juice sold in Canada is safe as it has been pasteurized (treated with heat or ultraviolet light) to kill harmful microorganisms. This includes most of the juice sold in refrigerated display cases, juice from concentrate and all shelf-stable products that are packaged in cans, bottles and juice boxes, which can be found unrefrigerated on grocery store shelves.

Most adults won't get seriously ill from drinking unpasteurized juice products, but vulnerable groups face more danger. This becomes more of a concern during the harvest season because schools often take students to orchards as part of class field trips, Health Canada notes.

First symptoms of a food-borne illness can include stomach cramps, vomiting, fever and diarrhea and can occur within two to 10 days of consuming contaminated food. People who experience any of these symptoms should contact their doctors immediately.