What is a leading cause in the spread of foodborne illness as proven by scientific research?

The leading cause in the spread of foodborne illness, as supported by scientific research, is poor personal hygiene. When food handlers do not practice good personal hygiene, such as failing to wash their hands properly after using the restroom or handling raw food, they risk contaminating food with harmful pathogens. These pathogens can then be ingested by customers, leading to foodborne illnesses.

Good personal hygiene is crucial in food handling because it directly impacts the safety of the food served. Handwashing with soap and water is the most effective way to remove bacteria and viruses that can cause illness. In environments like restaurants, where many people are served each day, the cumulative risk posed by a single food handler's negligence can be significant.

While other factors such as lack of training, poor food presentation, and excessive ingredient use can contribute to food safety issues, they do not directly correlate to the transfer of pathogens in the same way that poor personal hygiene does. Therefore, maintaining strict personal hygiene practices is essential for preventing foodborne illnesses in any food service operation.