Education in food hygiene is key to reducing food poisoning outbreaks, here in the UK we have fairly strict food hygiene regulations but outbreaks still occur and occasionally, some people die or suffer from the effects for years after the initial incident.,
Some of the main problems with street vendors are the following

• the lack of toilet and hand washing facilities, because vendors need to go to the toilet just like everyone else,
• poor temperature regulation of cooked and uncooked foods,
• cross contamination, where cooked and uncooked food come into contact with each other

The list goes on, these are some of the health risks associated with street food, education is key to at least limiting the occurrence of these outbreaks, as mentioned above, we have fairly strict regulations in the UK with fines and imprisonment for the worst offenders, we also have food hygiene certification as a means of determining a persons knowledge of the correct handling of food, vendors don't get to vend food if they don't have one since these are a prerequisite for obtaining a vendors licence,

btw excellent post