Division of Food Processing Science and Technology, U.S. Food and Drug Administration, 6502 South Archer Rd., Bedford Park, IL 60501, USA.
Institute for Food Safety and Health, Illinois Institute of Technology, 6502 South Archer Rd., Bedford Park, IL 60501, USA.
J AOAC Int. 2022 Jun 29;105(4):1092-1104. doi: 10.1093/jaoacint/qsac008.
Sprout growers in the United States are required to test spent sprout irrigation water (SSIW) or in-process sprouts for Escherichia coli O157:H7 and Salmonella species. Pathogen screening kits are commercially available; however, few have been validated for analysis of sprouts or SSIW.
This study evaluated AOAC-certified test kits (lateral flow devices [LFDs], enzyme immunoassays [EIAs], and molecular assays) in comparison with culture methods described in the U.S. Food and Drug Administration (FDA) Bacteriological Analytical Manual (BAM) for detection of Salmonella and E. coli O157:H7 in alfalfa SSIW.
Twenty-five milliliter aliquots of alfalfa SSIW, either uninoculated or inoculated with Salmonella or E. coli O157:H7 at a low (∼0.5-0.7 CFU/25 mL) or high level (∼10-20 CFU/25 mL), were subjected to the enrichment and assay protocols recommended by each test. Pathogen presence was confirmed following FDA BAM procedures and, if applicable, test kit manufacturer protocols.
Twelve of the 13 Salmonella test kits evaluated (except VIDAS UP) performed well and detected Salmonella in 100% of SSIW samples contaminated at 0.61 CFU/mL. Performance varied among E. coli O157:H7 test kits, with four (Reveal, MicroSEQ, GDS, MDA) of 12 kits designed for next-day detection, and four (Reveal, VIP Gold, MicroSEQ, GDS) of seven kits designed for same-day detection capable of detecting the pathogen in 100% samples contaminated at 0.90 CFU/mL.
Enrichment conditions play a key role in determining the performance of test kits and the success of confirmation.
This study is the first to compare a wide range of commercial test kits for detection of Salmonella and E. coli O157:H7 in SSIW.
美国的豆芽种植者必须对用过的豆芽灌溉水（SSIW）或加工中的豆芽进行大肠杆菌 O157:H7 和沙门氏菌检测。病原体筛选试剂盒可在商业上获得；然而，很少有试剂盒经过验证可用于分析豆芽或 SSIW。
本研究评估了与美国食品和药物管理局（FDA）BAM 中描述的培养方法相比，经过 AOAC 认证的测试试剂盒（侧流设备 [LFD]、酶免疫分析 [EIA]和分子分析）在检测苜蓿 SSIW 中的沙门氏菌和大肠杆菌 O157:H7 的性能。
25 毫升的苜蓿 SSIW 等分试样，未经接种或接种低水平（约 0.5-0.7 CFU/25 mL）或高水平（约 10-20 CFU/25 mL）的沙门氏菌或大肠杆菌 O157:H7，按照每个测试推荐的富集和检测方案进行处理。根据 FDA BAM 程序以及（如适用）测试试剂盒制造商的协议确认病原体的存在。
在所评估的 13 种沙门氏菌测试试剂盒中，有 12 种（VIDAS UP 除外）表现良好，可检测到 0.61 CFU/mL 污染水平的 SSWI 样本中的沙门氏菌 100%存在。E. coli O157:H7 测试试剂盒的性能各不相同，其中 12 种设计用于次日检测的试剂盒中有 4 种（Reveal、MicroSEQ、GDS、MDA）和 7 种设计用于当日检测的试剂盒中有 4 种（Reveal、VIP Gold、MicroSEQ、GDS）能够检测到 0.90 CFU/mL 污染水平的所有样本中的病原体。
富集条件在确定测试试剂盒的性能和确认的成功方面起着关键作用。
本研究首次比较了广泛的商业测试试剂盒用于检测 SSIW 中的沙门氏菌和大肠杆菌 O157:H7。
