Treats such as preserved jams and jellies,cookies, cakes and personalized packages of candies make crafty (andeconomical) homemade holiday gifts. But if the gift-givers whipped upthese and other goodies themselves, those delectables could be passingalong botulism too, reports MSNBC.

Food-bornebotulism is a paralyzing illness caused by botulinum spores. (Thesespores live on fresh food surfaces and die when exposed to air.) Whenfood gets canned, the process produces a low oxygen environment wherespores can linger and reproduce the harmful bacteria.

Whilebotulism cases are rare in the United States (the CDC reported 18 casesin 2008), it’s still important to watch out for home-cooked goods thatgo bad. And although you can’t spot a nasty spore just by looking atcanned foods, you can take steps to avoid getting sick from spoiledhome-cooked eats.

First, be cautious about eating low-acidichomemade canned foods, such as green beans, carrots, vegetable salsa,chocolate sauces and pestos. The lack of acid in these foods allowsspores to germinate, so home canning them in boiling water may not beenough to ensure they’re safe to eat. (In contrast, home-cannedhigh-acid foods, such as fruits, tomatoes with added lemon juice, andpickled products with a certain amount of vinegar, are usually OK.)

Second,ask questions. If you receive a home-cooked food gift, ask when and howthe giver made it and where he or she got the recipe. (Cooks shouldonly use tested recipes found on the United States Department ofAgriculture [USDA] website.) If you’re not happy with the gift-giver’sanswer, toss the food.

Next, check the jar.  Food shouldn’tstick out of the liquid and be discolored or moldy. If you notice anyof these unappetizing signs, then the food is probably not safe to eat.

Finally, if the food is canned, look for a vacuum seal. Why?Because the vacuum seal prevents contaminated air from getting backinto the product. If this seal is missing, it’s a sure sign the foodpreparer used improper and unhealthy canning techniques.

Click here to learn which popular party foods are often the most contaminated.