Often just the change in water can trigger upsets, but often it is in the food itself. Cooked foods that contain mayonnaise or dairy ingredients that have been left standing at room temperature are also at risk. Never eat foods bought from vendors on the street, eat only fruits that you peel yourself. Bottled water is available everywhere and some hotels provide it as part of the service. Use this even to brush your teeth as tap water even in large international hotels is not trustworthy.
Water comes in two forms - con gas or carbonated, and sin gas which is plain purified water.
The city of Lima is the center of Peru's fish and seafood industry - among the most prolific and varied in the world. Scallops, conchitas, and mussels, choros, are prepared in an infinite variety of tasty dishes including a lo macho which has a shellfish sauce. Corvina, or sea bass, a choice of shrimp or camarones from the rivers and Langostinos from the sea are more excellent choices from the sea, but trout from the Andean streams are some of the freshest and tastiest to be had anywhere. Good chicken and beef dishes are a staple but for a change of pace try anticuchos, tasty morsels of marinated beef heart on a shish kabob, or cuy, guinea pig which is a mountain specialty which is especially good in a peanut sauce. Pachamanca is another sierra specialty, a feast of meats and vegetables cooked together over heated stones in pits, rather like a luau.