Aerated Steam Sanitization of Whole Fresh Cantaloupes Reduces and Controls Rind‐Associated Listeriabut Enhances Fruit Susceptibility to Secondary Colonization

• Autores: Greg S. Bezanson, Timothy C. Ells, Lihua Fan, C. F. Forney, Denyse I. LeBlanc
• Localización: Journal of food science, ISSN 0022-1147, Vol. 83, Nº 4, 2018, págs. 1025-1031
• Idioma: inglés
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• Resumen

  • Recent bacterial illnesses and outbreaks associated with the consumption of fresh and fresh‐cut fruit and vegetables emphasize the need to supply produce that is microbiologically safe while retaining its quality and nutrient value. We assessed the capacity of aerated steam to reduce initial levels and control the posttreatment proliferation of a 4‐strain mixture of Listeria innocua, a surrogate for L. monocytogenes, and microflora native to the rind of whole cantaloupes. Studies were conducted at the pilot‐scale level by passing deliberately contaminated melons through a prototype stainless‐steel, continuous‐feed heating device. Exposure for 240 s to aerated steam heated to 85 °C achieved a mean reduction in surface‐inoculated L. innocuaof 3.9 ± 0.6 log10CFU/cm2(n= 3) and decreased background microorganisms (yeast, moulds, and coliforms) to undetectable levels. No significant outgrowth of surviving L. innocuaor yeast and moulds was observed on heat‐treated melons during their storage at 4, 7, and 10 °C for 14 days. Treated fruit continued to respire. Although rind quality was altered, edible fleshy portions remained largely unaffected. Cantaloupe inoculated with L. innocuasubsequent to its exposure to aerated steam provided a suitable environment for surrogate growth (mean 3.3 log10increase in rind density over 10 days at 7 °C), whereas its proliferation was restricted on nonheated cantaloupe (mean 0.7 log10increase). Steam sanitization provides an effective means for the control of pathogen and spoilage organisms, but the proliferation of surrogate organisms on heated cantaloupes raises concern regarding the impact of postprocessing contamination on consumer health risk. Water vapor (steam) at a high temperature can be used to sanitize the surface of fresh, whole cantaloupe melons in a continuous‐feed manner. Both Listeriabacteria and spoilage organisms are markedly reduced from initial levels and survivor outgrowth severely restricted during subsequent refrigerated storage. This approach to microorganism control is likely most applicable in situations where rinds and flesh are to be separated immediately via further processing.