in the city's famous market, the mercado ver-o peso, you can find cassava flour, brazil nuts, a rainbow of tropical fruits, and all sorts of other regional specialties. this stall sells one the market's most popular fruits -- acai berries. the somewhat sour and earthy palm tree fruit is packed with vitamins. everyone here loves them. >> before we had modern appliances, we mashed the berries by hand and pressed them through a sieve. now with these machines, it's much easier to puree the acai. reporter: the mashed acai is traditionally eaten with fried fish. the flood of diners at lunchtime certainly keeps the owner on his toes. the acai is doled out liberally and eaten plain without salt or spices. it's said the indigenous people here began eating it this way over 400 years ago. >> the berries have to be washed thoroughly, and then soaked in warm water. then they're dropped into these blenders -- we call them manipulation machines. then of course, there's the fish. we buy it fresh every morning. i filet them myself. we all have a particular job to do to ensure this famous dish is prepare