While buying foods in bulk can be cost-effective, cooking foods in bulk can be a great time-saving technique. Vegetables might not be your first choice of food to cook ahead of time, however, you can do so effectively -- as long as you’re careful about the reheating process.

Some vegetables are contaminated with bacteria when you purchase them from the store or market. From the farm to the market, fresh vegetables go through several different stages of processing -- including harvesting, cleaning, packaging and shipping. When cooked properly, the high temperatures can kill this bacteria and prevent it from harming your health. To eliminate dangerous bacteria during the reheating process, cook the vegetables to an internal temperature of at least 165 degrees Fahrenheit. Be sure to stir the vegetables several times during the reheating process to ensure even cooking.

Canned vegetables are a great option for stocking your pantry, as they have a tremendously long shelf life. However, the canning process can be a bit volatile. If the processing time was too short or the temperature was too low, the botulism toxin could develop. Although these toxins aren’t produced during the reheating process, improper reheating will not kill the toxin. To ensure safety when re-heating your canned vegetables, simmer them for at least 12 to 15 minutes before eating.

For the most part, reheating vegetables will not produce toxins. However, using a plastic container or plastic wrap to reheat your vegetables can be more dangerous. The Body Ecology website acknowledges that plastic often contains dangerous toxins that can leach into your food in the microwave. To be safe, reheat your vegetables in microwave-safe glass or ceramic dishes.

In 2005, the University of Minnesota issued a press release regarding a recent study done by University of Minnesota professor A. Saari Csallany and graduate student Christine Seppanen. The research study found that re-heating vegetable oil to high temperatures of at least 365 degrees Fahrenheit significantly increases the production of a highly toxic compound. The toxins continue to accumulate each time the oil is re-heated. This compound, 4-hydroxy-trans-2-nonemal, forms when linoleic acid oxidates during the heating process. The toxic compound has been linked to Alzheimer’s, atherosclerosis, Huntington’s disease, liver disease, Parkinson’s and stroke.