Which food is least likely to cause foodborne illness?

The reasoning behind identifying raw onions left out as the food least likely to cause foodborne illness relates to their inherent properties. Onions, particularly when they are whole, have a relatively low risk of harboring pathogens that lead to foodborne illnesses, especially in comparison to other options listed. When whole and uncut, onions create an environment that is less hospitable to bacteria, making them a safer choice.

While cookery and proper handling are essential for all food items to minimize risks, the other options entail higher risks due to their susceptibility to contamination. Cooked rice can be problematic if it is improperly stored and allowed to cool slowly, as it can foster the growth of Bacillus cereus. Raw meat is known for being a prime carrier of harmful bacteria and pathogens, requiring thorough cooking to ensure safety. Eggs can also be a source of Salmonella if not cooked adequately or handled properly. Thus, the safety profile of raw onions left out stands apart from those of cooked rice, raw meat, and eggs.