The microbiological safety of fish as food is a concern for consumers, industries and
regulatory agencies worldwide. The pathogenesis by Salmonella spp. derived from fish
is responsible for serious infections through inadequate handling or hygiene in the Fish
Processing Unit or through contact with water contaminated by a biological agent that
is not originally related to fish. The objective of this work was to evaluate the efficiency
of washing tambaquis (Colossoma macropomum) in a rotating cylinder to reduce
Salmonella spp. and propose a new initial washing protocol considering free chlorine
concentration and washing time. For this, fish were experimentally contaminated with
a Salmonella solution with an initial concentration of 1.5 x 106 CFU/mL and 20
treatments were tested, which consisted of washing only with water and washing with
different concentrations of chlorine (2, 5 and 10 ppm) with 5 washing times (20, 40, 60,
120 and 180 seconds) in the rotating cylinder, and the colorimetry of the fish was
performed after washing them in the cylinder, using the washing treatment that did not
grow of Salmonella colonies. Statistics showed that there was no significant difference
between treatments with different concentrations of chlorine, but there was a significant
difference between washing times, demonstrating a reduction in Salmonella as the
washing time increased. The experiment showed that in the time of 180 seconds at a
concentration of 10 ppm of chlorine there was no growth of Salmonella colonies on the
plate after washing, which meets the provisions of the legislation, absence of
Salmonella in 25g of fish. As there was a color change in the fish with this treatment,
future research should be carried out to verify consumer acceptability.
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