Final answer:
Leafy green vegetables grown with cow manure as fertilizer can contain E. coli bacteria, which can cause illnesses such as bloody diarrhea.
Step-by-step explanation:
Leafy green vegetables that have been grown in a field that uses cow manure as its primary fertilizer can contain E. coli. E. coli is a type of bacteria that can cause various illnesses, including bloody diarrhea. It is important to properly wash and cook vegetables to reduce the risk of contamination.