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

AbstractRecent 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. innocua of 3.9 ± 0.6 log10 CFU/cm2 (n = 3) and decreased background microorganisms (yeast, moulds, and coliforms) to undetectable levels. No significant outgrowth of surviving L. innocua or 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. innocua subsequent to its exposure to aerated steam provided a suitable environment for surrogate growth (mean 3.3 log10 increase in rind density over 10 days at 7 °C), whereas its proliferation was restricted on nonheated cantaloupe (mean 0.7 log10 increase). Steam sanitization prov...
Source: Journal of Food Science - Category: Food Science Authors: Tags: Food Microbiology & Safety Source Type: research