General Info
Large Brazilian cities have great supermarkets. Porto Alegre has some of the best I've seen anywhere in the world. Supermarkets in Leblon, Ipanema, and other Rio neighborhoods tend to be very crowded, because they're located where real estate is at a prime. Once you go to the suburbs, they increase in size dramatically. On the other hand, smaller supermarkets like Santa Luzia in the city of São Paulo have superb stuff, stocking only the best of everything, amazing selection of prewashed and precut veggies...incredible shopping experience. Also in Rio, Hortifruti (with several locations) carries wonderful fruits and vegetables.
Cashiers, as a rule, do not weigh bread or produce, you'll have to do that yourself when you bag them (or there's someone there to do it for you). For that and other reasons (shopping seems to be a family past-time in Brazil, so you may have a mother with four kids in front of you at the check-out line) it'll take more time to shop in Brazil than it does in the U.S. In spite of that, one of the things I enjoy the most when going to Brazil is food shopping. Going to the supermarket and checking out the different departments for Brazilian fruit drinks and pastes, soft and creamy cheeses like Queijo de Minas, Requeijão and Catupiry, and marvelous Brazilian sausages and salt meats. Don't be afraid to try them.
The frozen foods section keeps growing and growing and the stuff is very tasty, but as in the U.S., beware of sodium and MSG!
Don't forget that Brazilians use the metric system. When buying sliced ham, for instance, one hundred grams is about a quarter of a pound.
If you shop at your neighborhood supermarket, they'll usually deliver your groceries without any extra charge (at least they do so in Rio de Janeiro).
Meats
Although you may recognize meat cuts like pork chops and such, beef cuts are very different and prepackaged meats are not as prevalent. You'll notice that most meats are considerably leaner than in the U.S. Normally, good supermarkets will have a butcher who will cut and weigh the meats for you. Filet mignon is available, of course, if you can't think of anything else...
Also, as if you weren't confused enough, names of cuts will vary from Rio and São Paulo to the south of Brazil. In Rio and São Paulo, ask for "contra-filé" for steaks, "maminha" for roasts, "picanha" for barbecues (seen here), and "alcatra" for hamburguer. Buy your cut of meat and then ask for it to be minced (the expression is "passar na máquina"; ask them to do it twice). "Bisteca" is also a nice steak. Get a Brazilian cookbook in English that explains the different cuts.
Brazilian supermarkets also sell a variety of salt meats used in feijoada and other traditional dishes, and imported salt cod, which is used in dishes of Portuguese origin, like the fabulous "bolinhos de bacalhau."
Sausages are also completely different from what we eat in the U.S. Honestly, much better. You can try grilling them (here are some as served in a typical barbecue) or use them in a feijoada (be daring and try the recipe).
Chickens in Brazil taste delicious; it has to do with the way they are fed and the fact that they are not so fat. Try a "galeto" or very young chicken which you can buy already roasted. A lot of places called "'padarias" (bakeries) also sell spit-roast chickens. Both are very tasty and juicy, and - especially in the summer - you don't have to sweat in the kitchen to have a good meal. Just whip up a salad!
Milk and Other Dairy Products
Brazilians have a type of milk called Longa Vida (Long Life), which is sold in boxes and doesn't require refrigeration until it's opened. The best one I tasted actually came from the milk cooperative of Uruguay. In case you don't know, a few of the South American countries are members of Mercosul, a common goods market. See more under International Products. The Italian company Parmalat has been in Brazil for a while now: they sell all sorts of milk products in cute little cartons (you can find their products in the U.S. now).
The other strange way to sell milk is in liter-size plastic bags...I bet you never thought of that!
There are some marvelous yogurt and yogurt and fruit drinks in bottles in Brazil. My favorite yogurt is made of sheep milk and flavored with berries. My second favorite is made with Brazilian tropical fruits, such as graviola and cajá.
Brazilian supermarkets these days sell dozens of different cheeses, including some made from goat milk and a mix of goat and cow milks. I love the Brazilian cheeses I mentioned in the intro. You should try those; they're nothing like what we're used to here.
Try combining a slice of Minas cheese with a slice of guava (goiabada) or quince (marmelada) paste for a no-sweat, instant dessert Brazilians call "Romeu e Julieta."
Salamis and other cold cuts are sold with the cheeses and the variety is amazing (thanks to all those Italian and German immigrants!).
Fruits and Vegetables
Thoroughly talked about in "At the Feira" and Sherbets and Fruit Juices (with great photos to boot). If you're in Rio or São Paulo I would strongly recommend shopping at their superb street markets. São Paulo and Porto Alegre also have fabulous produce markets under one giant roof (Campinas also has a "Mercado Municipal," which is located downtown and is open on Sunday mornings.) Rio has the Cobal markets in Leblon and Humaitá.
Fruit Juices and Coconut Water
Fruit juices at the supermarket are sold either in glass bottles or in boxes that do not require refrigeration until opened. You'll need to dilute juices like cashew or passion fruit and add sugar to them because they're extremely tart. The juices are either just the fruit or fruit juice with soy. These seem to be very popular.
Don't pass up the opportunity to try the Brazilian soft drink called Guaraná made from Amazonian berries. It's loaded with caffeine and superior in taste to Coke or anything else in the U.S. Coconut water is sold in boxes (but I'd rather drink it fresh directly from the coconut!).
Breads and Pasta
Your supermarket will have a good selection of breads and pastas, which Brazilians eat a lot of. The best breads will probably come from your corner bakery ("padaria" in Portuguese), which also sells soft drinks, cheeses, cold cuts and a small selection of foodstuff. But I've bought baguettes from several supermarkets and they were delicious.
Cleaning Products
There are a lot of detergents and dish liquids in Brazil, try the ones made with coconut. Brazilians still use a lot of laundry soap bars, because they're cheaper and do an excellent job (not everyone has a washing-machine, ladies). I'm very partial to "sabão de coco" (coconut soap) which is simply the best to wash your delicate stuff.
Pet Foods
If you're taking your pooch or kitty to Brazil, tell them to say good-bye to the dozens of varieties of foods and treats and to learn to love leftovers and home-cooking. Pet foods are now available but still quite expensive. Most people buy bones and cheap cuts of meat and cook meals for their pets at home. Hard to believe? It's not only people that are spoiled rotten in the U.S., guys!
International Products
All the best supermarkets now have a considerable amount of goods from the U.S., Argentina, Uruguay and European countries So, yes, you will be able to buy American potato chips and cereals and so on, and French cheeses, and Chilean and Argentinian wines (woohoo!), etc. etc.