Carl Winter: Hi! My name is Carl Winter. I am a spokesperson for the Institute of Food Technologists. I'm also a Food Toxicologist on the faculty at the University of California, Davis.

Today I'm talking about food safety issues that resolve from the presence of potentially dangerous chemical contaminants in our food. In the last segment, we discussed the basic principles of toxicology, and how is the dose that makes the poison. It's the amount of a chemical rather than its presence or absence that determines the potential for harm. This is really important when we talk about chemical contaminants in the food supply because our laboratories are capable of detecting very tiny amount of chemicals in the food. So we can often identify the presence of these chemicals. The most important thing from a toxicological perspective is to determine whether those amounts are of health concern.

Fortunately, for most of the chemical contaminants that we find in the food supply, even though we can detect them, the amounts that we're exposed to are very, very low. In many cases, thousands or hundreds of thousands of times lower than amounts that we can feed laboratory animals that don't show any effects in those laboratory animals.

What I'll be talking about in the next segment will be how scientists determine what's an acceptable level of exposure to these chemicals, and then how some of these chemical contaminants compare with respect to those allowable levels.