Purpose: The purpose of this research is to evaluate the persistence of foodborne pathogens on the intact surface of whole Ataulfo, Kent, and Tommy Atkins mangoes stored at three different temperatures.
Methods: One hundred microliters of a five-strain rifampicin resistant Salmonella spp. or Listeria monocytogenes cocktail (six log CFU/mango) was spot inoculated onto the mid-section of whole fruit and dried for one hour. Fruit were stored at 12, 20, or 30 ± 2°C and sampled for up to 28 days. At each sampling point a mango was placed in a sterile bag with 10 ml of 0.1% peptone and bacterial populations were removed by a rub-shake-rub method. Pathogen populations were enumerated by plating onto selective and nonselective media supplemented with rifampicin. Experiments were replicated in duplicate three times for each variety (n=6).
Results: Populations of Salmonella increased over storage duration on the surfaces of Kent (0.3 to 1.1 log CFU/mango) and Tommy Atkins (0.2 to 1.4 log CFU/mango) mangoes at all temperatures. Salmonella populations on Ataulfo mangoes decreased at 12°C (1.6 log CFU/mango) and 30°C (0.4 log CFU/mango) but increased at 20°C (0.1 log CFU/mango). Listeria populations on the surface of Tommy Atkin mangoes increased at all temperatures ranging from 0.1 to 1.4 log CFU/mango.
Significance: These results imply that postharvest storage of mangoes will not result in sufficient microbial reductions to be used as corrective measures if agricultural water used during production does not meet the required standards of Produce Safety Rule.