By eating the amount of certain foods as shown on a food pyramid or food plate.
Exposure to Teratogen can cause defects if a foetus is exposed to it. There are several kinds of teratogens that can range (as mentioned in the question) from a chemical to a virus or radiations. Teratogen is the term used for any such agent that can result in harming the unborn baby due to exposure to it.
Most foodborne illness is caused by pathogenic bacteria or viruses in food
