Incidence, internalization and behavior of Salmonella in mangoes, var. Tommy Atkins

Abstract

Mangoes imported from South America were responsible for two Salmonella multistate outbreaks in the USA. The hot water immersion treatment utilized for fly larvae control was pointed out as the probably responsible for bacterial internalization in these fruits. The objective of this study was to evaluate: the presence of Salmonella in mangoes, the occurrence of internalization of these bacteria during a laboratory-simulated hydrothermal treatment and the bacterial behavior in mangoes in the rind surfaces and in different portions: stem end, middle side and blossom-end after storage at 8 and 22 °C, for 24 and 144 h. One hundred samples were analyzed; Salmonella was not found in any of the 33 samples destined for the export market, but in two of the remaining samples, destined for the internal market, the presence of that bacterium was detected. The results from the laboratory-simulated experiments proved that bacterial internalization occurred in the intact fruit. In the stem portion the log of MPN/g of bacteria was statistically higher than in the remaining parts of the fruit ( p < 0.05), demonstrating that the stem is the route for bacterial entrance. At 22 °C bacterial multiplication was observed in all portions (the rind surface, stem end, middle side and blossom-end) analyzed. However, at 8 °C the growth was lower, and in the rind surface there was a decrease in the number of bacteria. Thus, microorganisms present in the water used for hydrothermal treatments can migrate to the interior of mangoes, survive and grow in all fruit portions.