Tice George, Andaloro Bridget, Fallon Dawn, Wallace F Morgan
DuPont Qualicon, ESL Bldg 400, Rt 141 and Henry Clay, Wilmington, DE 19880, USA.
J AOAC Int. 2009 Nov-Dec;92(6):1902-5.
A recent outbreak of Salmonella in peanut butter has highlighted the need for validation of rapid detection methods. A multilaboratory study for detecting Salmonella in peanut butter was conducted as part of the AOAC Research Institute Emergency Response Validation program for methods that detect outbreak threats to food safety. Three sites tested spiked samples from the same master mix according to the U.S. Food and Drug Administration's Bacteriological Analytical Manual (FDA-BAM) method and the BAX System method. Salmonella Typhimurium (ATCC 14028) was grown in brain heart infusion for 24 h at 37 degrees C, then diluted to appropriate levels for sample inoculation. Master samples of peanut butter were spiked at high and low target levels, mixed, and allowed to equilibrate at room temperature for 2 weeks. Spike levels were low [1.08 most probable number (MPN)/25 g]; high (11.5 MPN/25 g) and unspiked to serve as negative controls. Each master sample was divided into 25 g portions and coded to blind the samples. Twenty portions of each spiked master sample and five portions of the unspiked sample were tested at each site. At each testing site, samples were blended in 25 g portions with 225 mL prewarmed lactose broth until thoroughly homogenized, then allowed to remain at room temperature for 55-65 min. Samples were adjusted to a pH of 6.8 +/- 0.2, if necessary, and incubated for 22-26 h at 35 degrees C. Across the three reporting laboratories, the BAX System detected Salmonella in 10/60 low-spike samples and 58/60 high-spike samples. The reference FDA-BAM method yielded positive results for 11/60 low-spike and 58/60 high-spike samples. Neither method demonstrated positive results for any of the 15 unspiked samples.
最近花生酱中沙门氏菌的爆发凸显了验证快速检测方法的必要性。作为AOAC研究所食品安全爆发威胁检测方法应急响应验证计划的一部分，开展了一项针对花生酱中沙门氏菌检测的多实验室研究。三个实验室根据美国食品药品监督管理局的《细菌学分析手册》（FDA-BAM）方法和BAX系统方法，对来自同一母液的加标样品进行检测。鼠伤寒沙门氏菌（ATCC 14028）在脑心浸液中于37℃培养24小时，然后稀释至适当浓度用于样品接种。花生酱母液样品分别添加高低两种目标水平的菌液，混合后在室温下平衡2周。加标水平分别为低水平[1.08最可能数（MPN）/25克]、高水平（11.5 MPN/25克），未加标的作为阴性对照。每个母液样品分成25克一份，并进行编码以对样品进行盲测。每个加标母液样品的20份和未加标样品的5份在每个实验室进行检测。在每个检测实验室，将25克样品与225毫升预热的乳糖肉汤混合，直至充分均质化，然后在室温下放置55 - 65分钟。如有必要，将样品pH值调至6.8±0.2，并在35℃下培养22 - 26小时。在三个报告实验室中，BAX系统在60份低加标样品中检测到10份沙门氏菌，在60份高加标样品中检测到58份。参考的FDA-BAM方法在60份低加标样品中有11份呈阳性结果，在60份高加标样品中有58份呈阳性结果。两种方法对15份未加标样品均未显示阳性结果。
