Performance characteristics of the temperature-modified ISO 9308-1 method for the enumeration of Escherichia coli in marine and inland bathing waters. (October 2018)

• Record Type: Journal Article
• Authors: Jozić, Slaven; Vukić Lušić, Darija; Ordulj, Marin; Frlan, Erina; Cenov, Arijana; Diković, Sonja; Kauzlarić, Vesna; Fiorido Đurković, Lara; Stilinović Totić, Jasmina; Ivšinović, Danijela; Eleršek, Nives; Vučić, Anita; Peroš-Pucar, Danijela; Unić Klarin, Branka; Bujas, Lidija; Puljak, Tatjana; Mamić, Mirna; Grilec, Dolores; Jadrušić, Marija; Šolić, Mladen
• Is Part Of: Marine pollution bulletin. Volume 135(2018)
• Page Start: 150
• Page End: 158
• Publication Date: 2018-10
• Subjects: Temperature-modified method -- Bathing water -- Escherichia coli -- Performance characteristics -- Chromogenic coliform agar; Marine pollution -- Periodicals; Marine Biology -- Periodicals; Water Pollution -- Periodicals; Mer -- Pollution -- Périodiques; Publications périodiques; Pollution des mers; Lutte antipollution; Electronic journals; 363.7394
• DOI: 10.1016/j.marpolbul.2018.07.002
• Languages: English
• ISSNs: 0025-326X

Abstract

Abstract: This study defines performance characteristics of the temperature-modified ISO 9308-1 method for E. coli enumeration in bathing water. After a 4-hour resuscitation period at 36 ± 2 °C, the incubation temperature was changed to 44 ± 0.5 °C. Elevated incubation temperature significantly suppressed the growth of thermo-intolerant bacteria, and enhanced the selectivity of Chromogenic Coliform Agar (CCA) up to 49.5% for inland and up to 66.0% for coastal water. Consequently, most of the selectivity-related performance characteristics are improved. Relative recovery was determined by comparing an alternative method against the reference, ISO 9308-1:2014 method, following the criteria set out in ISO 17994:2014. Temperature modification did not significantly alter the results and the methods were evaluated as "not different" for both, coastal and inland waters. Chromogenic Coliform Agar was assessed as a suitable medium for reliable E. coli enumeration in bathing water when incubated for 17–19 h at 44 ± 0.5 °C after the 4–5 h resuscitation period at 36 ± 2 °C. Graphical abstract: Highlights: A resuscitation period was crucial for E. coli recovery by the modified method. Relative recovery was high for both inland and coastal bathing water samples. Temperature modification significantly enhanced the selectivity of the method. All performance characteristics meet the requirements of ISO 13843:2017. The method was assessed as suitable for E. coli enumeration in bathing water.