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P2-201 Improvement of Modified Buffered Peptone Water with Sodium Pyruvate (mBPWp) Broth by Optimization of Composition Ratio of Supplements for Rapid Detection of Escherichia coli O157:H7

Tuesday, July 11, 2017
Exhibit Hall (Tampa Convention Center)
Hong-Seok Kim , Konkuk University , Seoul , South Korea
Jung-Whan Chon , U.S. Food and Drug Administration/NCTR , Jefferson , AR
Minjung Shin , Konkuk University , Seoul , South Korea
Dong-Hyeon Kim , Konkuk University , Seoul , South Korea
Young-Ji Kim , Konkuk University , Seoul , South Korea
Il-Byeong Kang , Konkuk University , Seoul , South Korea
Dana Jeong , Konkuk University , Seoul , South Korea
Jin-Hyeong Park , Konkuk University , Seoul , South Korea
Ho-Seok Chang , Konkuk University , Seoul , South Korea
Hyun-Woo Lim , Konkuk University , Seoul , South Korea
Kwang-Young Song , Konkuk University , Seoul , South Korea
Kun-Ho Seo , Konkuk University , Seoul , South Korea
Introduction: In order to ensure food safety and minimize the occurrence of foodborne illness, it is critical to promptly detect causative pathogens in foods. However, there is very little published information on media for shortening enrichment time. Nevertheless, the nucleic acid-based detection methods including PCR are rarely influenced by the number of competing flora.

Purpose:  The purpose of this study was to develop customized-enrichment media focused on rapid culture for ideal application of post-enrichment detection technologies.

Methods:  As a proof-of-concept study, we optimized modified buffered peptone water with sodium pyruvate (mBPWp; standard medium for enrichment of Escherichia coli O157:H7) for rapid culture of E. coli O157:H7 (mBPWpR) by comparison of growth curves according to the concentration of each supplement and incubation temperatures (42°C vs. 37°C). The performance of mBPWpR was compared to that of mBPWp for detecting healthy and cold-injured E. coli O157:H7 on mixed salad samples.

Results:  For rapid culture of E. coli O157:H7, the composition of mBPWpR was determined as follows: Lactose was excluded and the concentration of peptone was reduced to 2.5 g/L (25%). The mBPWpR was more effective for initial recovery of E. coli O157:H7 in mixed salads, as well as for pure cultures. For instance, at the inoculation level of 100 CFU/25g, E. coli O157:H7 was recovered from ca. 50% of samples. The cell numbers from the mixed salads were 2.33 ± 0.24 log CFU/mL vs. 1.81 ± 0.22 log CFU/mL in mBPWpR and mBPWp, respectively, after incubation for 8h at 42°C.

Significance: The results of this study showed that mBPWpR could be applied to real-time PCR detection, which is rarely inhibited by competing flora. It was, also, easily validated because the supplements for the broth are identical with those for original mBPWp. The data provided proof-of-concept that enrichment medium enhanced initial recovery of target bacterium and is suitable for rapid detection using PCR technique.

Back to: Poster Session 2 – Food Chemical Hazards and Food Allergens, Food Toxicology, Meat, Poultry and Eggs, Epidemiology, Retail and Food Service Safety, Communication Outreach and Education, Molecular Analytics, Genomics and Microbiome, Laboratory and Detection Methods, and Dairy
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