Food poison is the least thing you would want to deal with when you are off travelling far from home, enjoying breathtaking scenery, exploring new places and cultures, and being away from your old work-routines. But avoiding "traveller´s diarrhea" is not straight-forward, and least of all a certain science. I was clearly not well informed when I arrived to Bolivia and Peru. Fortunately, there are some straight-forward steps you can take to significantly reduce the risk of becoming affected.
Even though street food is often a rewarding step into the culture and life-styles of the native people, there is absolutely no guarantee of decent hygiene levels nor basic food safety in the preparation or preservation of the food. In Bolivia, it is highly recommended to avoid food from street vendors, but also keep in mind that meat is generally poorly treated hence making it a good host for bad bacteria.
In Peru, my friends warned me about eating lettuce, explaining that it can often be washed with unclean water, thus carrying bad bacteria with it. Home-made mayonnaise and other sauces are also items to be cautions about, as there is no guarantee how long they have been left out. During my 10-days stay in Peru, I ate mainly chicken with french-fries, with exception for the lasagna and pizza that were occasionally offered!
Here are some steps to avoid food poisoning:
1) Do not drink tap water! - Stay true to bottled / boiled water! Hence, avoid food that can have been washed or in contact with dirty water; (ex. ice).
2) Do not eat fruit or veggies that cannot be peeled. Especially not leafy veggies like lettuce or spinach.
3) Ensure that your food is thoroughly and recently cooked, served right-out-of-the-oven so to speak. Thus, avoid buffets, ice cream bars, home-made sauces (although sealed packages are mostly safe).
To sum it up: "Cook it, wash it, peel it or forget it".
What to do if you get food poisoning:
I was told by a doctor in Sweden that antibiotics is usually not needed in the "western" world, as you will start to recover within a few days. However, it is not a bad option when travelling in Asia or Central / South America.
Hydration:
The most important thing to keep in mind is to stay hydrated. On my very laborious trips outside my bed room, I bought bread, bananas, and 2 lt bottles of water in which I added a good amount with salt and sugar from the cafeteria. Furthermore, "white food", like rice, white bread, banana is recommended to eat, and the salt and sugar from the water will keep you replenished on salt and your energy level a little higher.
Private bathroom:
Not only is it convenient to have a toilet close by, but for the safety of the people around you, it is highly recommended to not share the bathroom with others. This will reduce the likelihood of spreading the bacteria to others. For this reason, it is vital that you are extremely tentative with your hygiene. (Always wash your hands after using the bathroom, with soap!)
Here are some good reads of how to avoid what non of want to go through while travelling: