Thomas Crampton has posted some advices on food when you are travelling – should you be careful on what you are eating and drinking. Generally he suggests you can eat everything that has been peeled, grilled or boiled. The most important thing is to wash hand before eating:
… Basically, I never eat anything that has been washed in tapwater (like lettuce) and avoid anything that has milk products (pies with cream or other milk products that can go bad in tropical heat) but you can eat almost anything that has been peeled (fruit) grilled (meat) boiled (soup, noodles, curries, etc). Always wash hands before eating and get in the habit of carrying purell in your pocket. Be wary of cutlery in the sense that you should rub it down with a napkin before using it…
Some of the comments in there are pretty informative as well – Like a link to Tips and Safe and Healthy Travel site, discussion on what is purell etc.
Eating while travelling – [Joi Ito's Web]