A number of bacterial illnesses may arise from the consumption of seafood that has either been contaminated at source or which becomes contaminated during the processing and retail chain. Such illnesses may arise from infection with the bacteria themselves or by the ingestion of toxins formed in the foodstuff prior to consumption. This division is actually too simplistic: for example, the toxins of Clostridium botulinum and Staphylococcus aureus are preformed in food during bacterial growth, the toxin of Clostridium perfringens is usually only formed when the bacteria sporulate in the intestinal tract while the toxin of Vibrio cholerae O1 (and O139) is produced when the bacteria multiply in the intestinal tract.