The most common reason for food born illness is contamination of the food. If the food is exposed to things such as animal feces or workers handling the product with dirty hands, then there is a risk of contamination.
poor personal hygiene
what is the common cause of the food borne illness
A food borne illness is an illness that can only be contracted when you eat it. Some meats have things in them that can make you sick if you do not cook them thoroughly, this is a food borne illness.
To prevent the spread of illness through food
To prevent spreading illness through contaminated food.
The most common illness caused by a food-borne pathogen would be diarrhea and intestinal cramps, such as what is caused by ingestion of pathogenic Salmonella.
The main reason would be to prevent foodborne illness. A second reason would be to prevent spoilage.
C. botulinum, E. coli, and salmonella
That would be Salmonella.
Same reason potatoes were so common in Ireland, I suppose!