Quantifying hydrocooling water infiltration in ‘Palmer’ mangoes following hot-air quarantine treatment

Around the world hot-air heating is used as a quarantine treatment to control fruit fly larvae in mangoes. To simulate hydrocooling water absorption in mangoes subjected to hot-air heating quarantine treatment, the internalization of acid blue 9 dye was tested. Hot-air heating fruits (45 °C) had higher acid blue 9 dye infiltration (2.26 %) compared to untreated control fruits (0.72 %). Higher dye infiltration was observed in heated fruits (2.97 %) after 15 min of cold-water immersion than the 60 min required for 1.84 % infiltration in unheated fruits. Regardless of treatment, dye infiltration occurred uniformly through the lenticels on the pericarp and occasionally through the stem into the mesocarp. Thus, hot-air heating treatment followed by immersion in cold water results in fast water infiltration, potentially allowing the internalization of food-borne pathogens if the cooling water is not properly treated. • Hydrocooling can lead to the internalization of food-borne pathogens. • Heating the mangoes for 15 min was sufficient for maximum blue acid dye 9 absorption. • Dye absorption occurred uniformly through the lenticels on the skin. • Dye absorption occurred occasionally through the stem into the mesocarp. • Hydrocooling water needs to be treated with disinfectants to prevent pathogen internalization.