BACKGROUND Most hydroponic lettuce growers harvest and package their marketable size lettuces with an intact root ball. With a high microbial load on the peat moss substrate, there is a risk of microbial transfer unto the edible portion during packaging and throughout the product's shelf life. Since the produce is believed to have no contact with the substrate, no sanitizer wash is performed before packaging and storage. RESULTS Aerobic plate count (APC) results suggested that reduction in count was influenced by both sanitizer application and storage time. Peroxyacetic acid (PAA) significantly reduced APC count on leaves, roots, and substrate with a 1.8 log CFU/g initial reduction on the leaf. Fungi and APC levels increased with storage time, with the greatest APC increase in the roots. Leaves had the lowest coliform bacteria (CB), with chlorine slightly reducing CB count. Unlike APC, CB levels decreased during storage on the substrate and root samples. No Listeria positive was confirmed by agglutination test. Further evaluation of different commercial substrates reveals that Com4, a drier-compacted plug, had the least ability to support growth/survival of all microbial populations enumerated relative to the spongy, wet black plugs. CONCLUSION The ability of peat moss substrates to host microorganisms is influenced by the physical properties of the product. Sanitizer wash efficacy is dependent on the initial microbial load and the length of storage. Chlorine and PAA are effective in reducing microbial populations on the leaves of hydroponically grown lettuce without affecting visual quality during shelf life. This article is protected by copyright. All rights reserved.

中文翻译：

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消毒剂在减少商业种植水培生菜微生物负荷方面的功效


背景技术大多数水培生菜种植者收获并包装具有完整根球的适销尺寸的生菜。由于泥炭藓基质上的微生物负荷较高，因此在包装期间和产品的整个保质期内存在微生物转移到可食用部分的风险。由于产品被认为不与基材接触，因此在包装和储存之前不进行消毒清洗。结果 需氧菌平板计数 (APC) 结果表明，计数减少受到消毒剂使用和储存时间的影响。过氧乙酸 (PAA) 显着减少了叶子、根和底物上的 APC 计数，叶子上的初始减少量为 1.8 log CFU/g。真菌和 APC 水平随着储存时间的延长而增加，其中根部的 APC 增加最多。叶子的大肠菌群 (CB) 含量最低，氯会略微降低 CB 数量。与 APC 不同，在基质和根样品上储存期间，CB 水平会下降。凝集试验未证实李斯特菌阳性。对不同商业基质的进一步评估表明，相对于海绵状湿黑色塞，Com4（一种干燥压实的塞）支持所有列举的微生物种群生长/存活的能力最低。结论 泥炭藓基质对宿主微生物的能力受到产品物理特性的影响。消毒剂清洗效果取决于初始微生物负荷和储存时间。氯和 PAA 可有效减少水培生菜叶子上的微生物数量，且不会影响保质期内的视觉质量。本文受版权保护。版权所有。