Imported papayas from Mexico have been implicated in multiple salmonellosis outbreaks in the United States in recent years. While postharvest washing is a critical process to remove latex, dirt, and microbes, it also has the potential of causing cross-contamination by foodborne pathogens, with sponge or other fibrous rubbing tools often questioned as potential harboring or transmitting risk. In this study, Salmonella inactivation and cross-contamination via sponges and microfiber wash mitts during simulated papaya washing and cleaning were investigated. Seven washing treatments (wash without sanitizer; wash at free chlorine 25, 50, and 100 mg/L, and at peracetic acid 20, 40, and 80 mg/L), along with unwashed control, were evaluated, using Salmonella strains with unique antibiotic markers differentially inoculated on papaya rind (serovars Typhimurium, Heidelberg, and Derby) and on wash sponge or microfiber (serovars Typhimurium, Newport, and Braenderup). Salmonella survival and transfer on papaya and on sponge/microfiber, and in wash water were detected using selective plating or enrichment. The washing and cleaning process reduced Salmonella on inoculated papayas by 1.69–2.66 and 0.69–1.74 log for sponge and microfiber cleaning, respectively, with the reduction poorly correlated to sanitizer concentration. Salmonella on inoculated sponge or microfiber was under detection limit (1.00 log CFU/cm²) by plate count, but remained recoverable by selective enrichment. Transference of Salmonella from inoculated papaya to sponge/microfiber, and vice versa, could be detected sporadically by selective enrichment. Sponge/microfiber mediated Salmonella cross-contamination from inoculated to uninoculated papayas was frequently detectable by selective enrichment, but rendered undetectable by wetting sponge/microfiber in sanitizing wash water (FC 25–100 mg/L or PAA 20–80 mg/L) between washing different papaya fruits. Therefore, maintaining adequate sanitizer levels and frequently wetting sponge/microfiber in sanitizing wash water can effectively mitigate risks of Salmonella cross-contamination associated with postharvest washing, especially with regard to the use of sponge or microfiber wash mitts.

近年来，从墨西哥进口的木瓜与美国多次沙门氏菌病的爆发有关。虽然收获后清洗是去除乳胶，污垢和微生物的关键过程，但它也有可能引起食源性病原体的交叉污染，而海绵或其他纤维揉搓工具经常被怀疑具有潜在的隐匿或传播风险。在这项研究中，沙门氏菌灭活和交叉污染通过模拟木瓜洗涤和清洁过程中的海绵和超细纤维洗涤手套。使用沙门氏菌，评估了七种洗涤处理方法（不使用消毒剂进行洗涤；以游离氯25、50和100 mg / L以及以过乙酸20、40和80 mg / L洗涤）以及未洗涤的对照液。带有独特抗生素标记的菌株在木瓜皮（鼠伤风杆菌，海德堡和德比）和洗海绵或超细纤维（鼠伤风杆菌，纽波特和Braenderup）上差异接种。沙门氏菌在木瓜和海绵/超细纤维上以及在洗涤水中的存活和转移都可以通过选择性平板接种或富集检测。对于海绵和超细纤维的清洗，洗涤和清洁过程分别将木瓜接种沙门氏菌减少了1.69–2.66和0.69–1.74 log，减少的程度与消毒剂浓度相关性很低。通过平板计数，接种的海绵或超细纤维上的沙门氏菌含量低于检出限（1.00 log CFU / cm ²），但通过选择性富集仍可恢复。转让通过选择性富集可以偶尔检测从接种木瓜到海绵/超细纤维的沙门氏菌，反之亦然。海绵/超细纤维介导的从接种木瓜到未接种木瓜的沙门氏菌交叉污染通常可以通过选择性富集检测到，但在清洁过程中用海绵/超细纤维在洗涤水（FC 25-100 mg / L或PAA 20-80 mg / L）中进行消毒后却无法检测到。洗不同的木瓜水果。因此，保持足够的消毒剂水平并经常在清洁洗涤水中弄湿海绵/超细纤维可有效减轻与收获后洗涤相关的沙门氏菌交叉污染的风险，尤其是在使用海绵或超细纤维的清洁手套时。