7 9 Vol. 7 No. 9 2016 9 Journal of Food Safety and Quality Sep., 2016 A B C 1, 代晓航 2 1,, 郭灵安 2*, 魏超 (1., 610066; 2. ( ), 610066) 1, 2 摘要 : 目的 3 SEA SEB SEC 方法, 10 4 CFU/g ( ) 10 2 CFU/g ( ),, 8 25, GB 4789 (A-C) 结果,,, SEA SEB SEC, 25, 10 4 CFU/g SEA, 10 5 CFU/g SEC, 10 7 CFU/g SEB; 8, 48 h 结论, 3, 关键词 : ; ; Study of staphylococcal enterotoxins A, B, and C expression on strawberry DAI Xiao-Hang 1, 2, GUO Ling-An 1, 2*, WEI Chao 1, 2 (1. Analysis and Testing Center of Sichuan Academy of Agricultural Sciences, Chengdu 610066, China; 2. Security Risk Assessment Laboratory of Ministry of Agriculture (Chengdu), Chengdu 610066, China) ABSTRACT: Objective To investigate the correlation between the growth of Staphylococcus aureus (SA) and expression of staphylococcal enterotoxins (SE) including SEA, SEB and SEC on strawberry. Methods The enterotoxin strains were confirmed, 10 4 CFU/g and 10 2 CFU/g of bacteria were prepared and artificial pollution to the strawberry by immersion method. According to GB 4789, SA and staphylococcal enterotoxins (A-C) of strawberry were counted and detected in the storage process of 8 and 25. Results Under the suitable conditions, regardless of initial contamination level of SA in strawberry could normal growth and produce enterotoxin, especially the production of SEA was higher than that of SEB and SEC quickly. Among them, SEA could be detected from the sample when SA accumulated to more than 10 4 CFU/g at 25 storage conditions, accumulated to more than 10 5 CFU/g would be able to detect SEC, accumulated to more than 10 7 CFU/g would be able to detect SEB. SE were not detected at 8 within 48 h. Conclusion The correlation between the growth of SA and expression of SE on strawberry were studied, which would be valuable to the microbiological risk assessment and standards setting of strawberry. 基金项目 : (GJFP201601302) Fund: Supported by National Major Projects for Risk Assessment of Agricultural Products Quality and Safety (GJFP201601302) * 通讯作者 :,, E-mail: gla028@163.com *Corresponding author: GUO Li-An, Associate Researcher, Analysis and Testing Center of Sichuan Academy of Agricultural Sciences, Chengdu 610066, China. E-mail: gla028@163.com
9, : A B C 3517 KEY WORDS: strawberry; Staphylococcus aureus; staphylococcal enterotoxins 1 引言,,,,,,,,,,, [1,2],,, 33%,, 1957~2012 106, 6.93%( 6 ) [3] 23, SEA-SEF SEG-SET SELU-SELX TSST-1 [3-7] SEA [8],, 10 5 CFU/g, 1 μg,,,,,, 2 材料与方法 2.1 材料 : 142 : NaCl (, ) 0.1% A-C, 7.5%NaCl, BP,, : DHP-9082 ( ) Mini-bk ( ) DW-Hl100 ( ) 2.2 方法 2.2.1 金黄色葡萄球菌收集 142, [9] -70 2.2.2 菌液制备及染菌 0.5, 0.1%, 10 4 CFU/g( ) 10 2 CFU/g( ),,, 7.5%NaCl (36 ),, 2.2.3 贮存及检测 2~4, 0~25,, 2, 8 25, 8, 25,, 8 12 h, 25 5 h, 2, 3 结果与分析 3.1 金黄色葡萄球菌收集结果 142 3, 2% 3 3.2 菌落计数结果, 10 4 CFU/g 10 2 CFU/g, 3, 3, SEA SEB SEC 1 C T, 10 ng/ml, A B C, SEA SEC, SEA SEB SEC, [10] 2 3.3 不同贮存条件下高低初始污染量对金黄色葡萄球菌产毒素的影响 3.3.1 25 贮存条件下产毒素情况 25, 1 2
3518 7 Fig. 1 1 The results of staphylococcal enterotoxins detection 表 1 25 贮存条件下草莓中金黄色葡萄球菌产毒素结果 Table 1 The results of staphylococcal enterotoxins expression at 25 storage (h) 5 10 15 20 25 30 35 G/D G/D G/D G/D G/D G/D G/D /+ SEA /+ /+ SEB /+ - + SEC /+ /+ G: ; D: : +: ; -: ; : G: Sample with high pollution; D: Sample with low pollution; +: Positive; -: Negative; : Not analyzed 2 25 Fig. 2 Growth of Staphylococcus aureus at 25 storage in the strawberry 2, D D, G G, 25, 5 h 1 2, 3 SEA SEC SEB, SEA 5h 25 h,, 10 4 10 5 CFU/g SEC 10 h 25 h,, 10 5 10 6 CFU/g, SEB 25 h 35 h,, 10 7 10 8 CFU/g, 3,, SEA,,,, SEA SEB SEC
9, : A B C 3519 表 2 8 贮存条件下草莓中金黄色葡萄球菌产毒素情况 Table 2 The results of staphylococcal enterotoxins expression at 8 storage (h) 12 24 36 48 G/ D G/ D G/ D G/ D SEA -/ SEB SEC G: ; D: : +: ; -: ; : G: Sample with high pollution; D: Sample with low pollution; +: Positive; -: Negative; : Not analyzed [11],, SEA 3.3.2 8 贮存条件下产毒素情况 8 2 3 48 h SEA SEC SEB 4 结论,,,,,,, 6l gcfu/g, 23 32 7l gcfu/g [12-15], ph,,, SEA, 10 4 10 5 CFU/g,, SEB SEC 参考文献 3 8 Fig. 3 Growth of Staphylococcus aureus at 8 storage in the strawberry 3, D D, G G,,, [1],,,. VITEK [J]., 2007, 28(3): 320 323. Pan J, Huang XD, Xie HM, et al. Experiment of hygienical microbiology examination and bacteria identification by VITEK for strawberry [J]. Food Sci, 2007, 28(3): 320 323. [2],,,. [J]., 2014, 27(6): 2534 2538. Wei C, Guo LA, Hu Li, et al. Pesticide residues detection of strawberries
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