Is Government covering up source of food Botulism?

It has been said never shake hands with someone who lives in a culture where toilet paper is a luxury item. It is also said they should not pick your fruits and vegetables either. Spinach, Lettuce and now tomatoes showing up with botulism. Then there are the meat packing plants with recalls due to botulism tainted meat. What both have in common are foreign workers who come from a culture where you don't drink the water. In fact federal law prohibits fruit or vegetables to be served at US schools picked just a few miles south of San Diego. I have watched vegetables in California being picked and also saw some of the workers urinate and defecate in the field. I saw no toilet paper and no hand washing and I am sure the rain helped the plants absorb the human waste (not good). So with my 40 minute observation yielding this why can't the government find the source of the botulism outbreaks? Do they know and just do not want to offend an ethnic voting block regardless of public safety?