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. 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 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. PRACTICAL APPLICATION 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 Listeria bacteria 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.

中文翻译：

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对整个新鲜哈密瓜进行充气蒸汽消毒可减少和控制与果皮相关的李斯特菌，但会提高果实对二次定殖的易感性

最近与食用新鲜和鲜切水果和蔬菜相关的细菌性疾病和爆发强调需要提供微生物安全的产品，同时保持其质量和营养价值。我们评估了充气蒸汽降低初始水平和控制 4 株无害李斯特菌混合物（单核细胞增生李斯特菌的替代物）和整个哈密瓜外皮原生菌群的处理后增殖的能力。通过将故意污染的甜瓜通过原型不锈钢连续进料加热装置，在中试规模进行了研究。暴露于加热至 85 °C 的充气蒸汽 240 秒后，表面接种的无害乳杆菌平均减少 3.9 ± 0.6 log10 CFU/cm2 (n = 3)，并减少了背景微生物（酵母、霉菌、和大肠菌群）到无法检测到的水平。在经过热处理的甜瓜在 4、7 和 10 °C 下储存 14 天期间，未观察到存活的无害乳杆菌或酵母菌和霉菌的显着生长。处理过的水果继续呼吸。尽管外皮质量发生了变化，但可食用的肉质部分基本上没有受到影响。在暴露于充气蒸汽后接种 L. innocua 的哈密瓜为替代生长提供了合适的环境（在 7 °C 下 10 天内，外皮密度平均增加 3.3 log10），而其在未加热哈密瓜上的增殖受到限制（平均增加 0.7 log10 ）。蒸汽消毒为控制病原体和腐败生物提供了有效的手段，但是，加热的哈密瓜上的替代生物的扩散引起了人们对后处理污染对消费者健康风险的影响的担忧。实际应用 高温水蒸气（蒸汽）可用于以连续进料方式对新鲜的整个哈密瓜表面进行消毒。李斯特菌和腐败微生物均从初始水平显着减少，并且在随后的冷藏过程中，幸存者的生长受到严重限制。这种微生物控制方法可能最适用于通过进一步加工立即分离果皮和果肉的情况。李斯特菌和腐败微生物均从初始水平显着减少，并且在随后的冷藏过程中，幸存者的生长受到严重限制。这种微生物控制方法可能最适用于通过进一步加工立即分离果皮和果肉的情况。李斯特菌和腐败微生物均从初始水平显着减少，并且在随后的冷藏过程中，幸存者的生长受到严重限制。这种微生物控制方法可能最适用于通过进一步加工立即分离果皮和果肉的情况。