Development of modified enrichment broth for short enrichment and recovery of filter-injured Salmonella Typhimurium

• Published in: International journal of food microbiology Vol. 362; p. 109497
• Main Authors: Kim, Unji, Moon, Ye-Ji, Kim, Jin-Hee, Lee, So-Young, Oh, Se-Wook
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 02.02.2022; Elsevier BV
• Subjects: Additives; Bacterial growth; Brassica; Brassica oleracea; Culture Media; Curve fitting; Enrichment; Filtration; Food Microbiology; Foodborne pathogens; Growth curves; Injured pathogen; Injury prevention; Magnesium; Magnesium sulfate; Pathogens; Peptones; Proline; Pyruvic acid; Rapid detection; Resuscitation; Salmonella; Salmonella Typhimurium; Short enrichment; Sodium pyruvate; Bacterial growth; Filtration; Rapid detection; Injured pathogen; Short enrichment
• ISSN: 0168-1605; 1879-3460
• DOI: 10.1016/j.ijfoodmicro.2021.109497

The filter concentration method facilitates the rapid detection of foodborne pathogens. The filter concentration method lowered the limit of detection (LOD) of artificially inoculated cabbage with Salmonella Typhimurium; however, the procedure injured foodborne pathogens during filtering procedure. Thus, to detect injured pathogens under the detection limit, an enrichment broth promoting pathogen resuscitation and growth is required. To rapidly recover, cultivate and lower the time to result (TTR) of S. Typhimurium detection after filter concentration method, a brain heart infusion (BHI) broth-based modified enrichment broth (MEB) was developed. The MEB was developed by fitting growth curves to a modified Gompertz model; 1.00 g/L of sodium pyruvate, 0.20 g/L proline and 2.0 g/L magnesium sulphate additives were optimized as additional components to rapidly grow filter-injured S. Typhimurium. As a result, the rate of filter-injured S. Typhimurium went from 100% to 0.0% using MEB within 3.5 h. In contrast, BHI required 4 h and buffered peptone water (BPW) required more than 4 h to decrease the injury rate to 0.0%. Using MEB, BHI and BPW, filter-injured S. Typhimurium in cabbages were enriched to 4.056 ± 0.026 Log CFU/25 g, 3.571 ± 0.187 Log CFU/25 g and 3.708 ± 0.156 Log CFU/25 g, respectively. Additionally, 1–9 CFU/mL S. Typhimurium in cabbage was detected within 3.0 h, including 1 h enrichment with MEB, whereas 5.0 h was required for BHI and BPW. Thus, the MEB developed in this study showed great potential as a short enrichment broth for the rapid detection of filter-injured S. Typhimurium. •Filter concentration method produced injured Salmonella Typhimurium.•Sodium pyruvate, proline and magnesium sulphate activated Salmonella Typhimurium.•Modified enrichment broth recovered Salmonella Typhimurium entirely within 3.5 h.•This detected filter-injured foodborne pathogen within 3.0 h with 1.0 h enrichment.