Jung Jiin, Friedrich Loretta M, Danyluk Michelle D, Schaffner Donald W
1 Department of Food Science, Rutgers University, 65 Dudley Road, New Brunswick, New Jersey 08901-8520; and.
2 Department of Food Science and Human Nutrition, Citrus Research and Education Center, University of Florida, 700 Experiment Station Road, Lake Alfred, Florida 33850, USA.
J Food Prot. 2017 Jun;80(6):933-939. doi: 10.4315/0362-028X.JFP-16-423.
Although studies have quantified bacterial transfer between hands and various materials, cross-contamination between the surface of fresh citrus fruit and the edible portions during hand peeling has not been reported. This study quantifies transfer of Salmonella to the edible portion of citrus fruit from a contaminated peel during hand peeling. Citrus fruits used for this study were Citrus sinensis (sweet orange) cultivars 'Valencia' and 'Navel', Citrus unshiu (Satsuma mandarins), Citrus reticulata × Citrus paradisi ('Minneola' tangelo or 'Honeybell'), and C. paradisi (grapefruit) cultivar 'Marsh'. An avirulent Salmonella Typhimurium LT2 (ATCC 700720) resistant to rifampin was used for all experiments. The inoculum containing approximately 9 log CFU/mL (50 μL) was spot inoculated onto the equator, stem, or styler of each fruit and allowed to dry for 24 h. Six volunteers put on single-use latex gloves and peeled inoculated fruit. Peel, edible fruit portion, and gloves were collected and enumerated separately. Three replicates of the study were performed in which each volunteer peeled two inoculated fruit of each variety (n = 36 fruit per variety). Cross-contamination from contaminated surface of citrus fruits to edible portion or gloved hands during peeling was affected by inoculation sites. Average Salmonella transfer to the edible portion ranged from 0.16% (Valencia inoculated at the equator) to 5.41% (navel inoculated at the stem). Average Salmonella transfer to gloved hands ranged from 0.41% (grapefruit inoculated at the stem) to 8.97% (navel inoculated at the stem). Most Salmonella remained on the peel of citrus fruits. The average level of Salmonella remaining on the peel ranged from 5.37% (Minneola inoculated at the equator) to 66.3% (Satsuma inoculated at the styler). When grapefruit was inoculated, the Salmonella that remained on the peel showed a bimodal pattern in which some individuals left almost all Salmonella on the peel, while others left substantially less.
尽管已有研究对双手与各种材料之间的细菌转移进行了量化，但尚未有关于徒手剥皮时新鲜柑橘类水果表面与可食用部分之间交叉污染的报道。本研究量化了徒手剥皮过程中沙门氏菌从受污染的果皮转移至柑橘类水果可食用部分的情况。本研究使用的柑橘类水果包括甜橙品种“巴伦西亚”和“脐橙”、温州蜜柑、“明尼奥拉”坦普尔橘柚（或“蜜钟”）以及葡萄柚品种“马什”。所有实验均使用对利福平耐药的无毒鼠伤寒沙门氏菌LT2（ATCC 700720）。将含有约9 log CFU/mL（50 μL）的接种物点接种到每个水果的赤道、果柄或花柱部位，使其干燥24小时。六名志愿者戴上一次性乳胶手套，对接种过的水果进行剥皮。分别收集果皮、可食用的水果部分和手套并进行计数。该研究进行了三次重复，每位志愿者对每个品种的两个接种过的水果进行剥皮（每个品种n = 36个水果）。剥皮过程中，柑橘类水果受污染表面向可食用部分或戴手套的手的交叉污染受接种部位影响。沙门氏菌转移至可食用部分的平均比例从0.16%（赤道接种的巴伦西亚橙）到5.41%（果柄接种的脐橙）不等。沙门氏菌转移至戴手套的手的平均比例从0.41%（果柄接种的葡萄柚）到8.97%（果柄接种的脐橙）不等。大多数沙门氏菌仍留在柑橘类水果的果皮上。留在果皮上的沙门氏菌平均水平从5.37%（赤道接种的明尼奥拉坦普尔橘柚）到66.3%（花柱接种的温州蜜柑）不等。当葡萄柚接种后，留在果皮上的沙门氏菌呈现双峰模式，即一些个体几乎将所有沙门氏菌留在果皮上，而另一些个体留下的则少得多。
