[Someone1234]

And from my understanding a lot of packaged food is intentionally irradiated after it has been sealed. Here's an FDA article about the process:

http://www.fda.gov/Food/ResourcesForYou/Consumers/ucm261680....

So aside from contamination, those sandwiches are likely slightly safer than from other places since the radiation in the area will help sanitise surfaces and foods.

My only concern would be if the water staff used to wash up was contaminated from the soil. But assuming the water is good the food is likely good too.