Rapid Detection of Listeria in Ice Cream in 13 Hours Using the Roka Listeria Detection Assay

• Published in: Journal of AOAC International Vol. 101; no. 6; pp. 1806 - 1812
• Main Authors: Arias-Rios, Elba Veronica, Tenney, Kristina, Mai, Tam, Anderson, Sam, Cantera, Ruth Marie, Nadala, Lourdes M, Han, Sukkyun, Janagama, Harish, Pando, Jasmine M, Selover, Brandon, Lei Sung, Shao, Nadala, Cesar, Samadpour, Mansour
• Format: Journal Article
• Language: English
• Published: United States 01.11.2018
• Subjects: Bacterial Typing Techniques - methods; Culture Media; Food Microbiology - methods; Ice Cream - microbiology; Listeria - genetics; Listeria - isolation & purification; RNA, Bacterial - analysis; RNA, Ribosomal - analysis
• ISSN: 1060-3271; 1944-7922
• DOI: 10.5740/jaoacint.18-0108

contamination is a major concern in the ice cream industry; therefore, early and accurate detection is vital. Current detection methods require about a 24 h enrichment period for detection. Enhance the early detection of in ice cream using the highly sensitive isothermal ribosomal RNA-based Roka/Atlas Detection Assay. The R2 Medium was developed for enrichment by Molecular Epidemiology, Inc. (Seattle, WA). Comparative growth curve studies were performed on the new R2 Medium for and the currently validated media for the Roka Detection Assay. Subsequently, a method comparison between the Roka Detection Assay and the U.S. Food and Drug Administration's (FDA) (BAM) Chapter 10 reference method on ice cream was carried out. The R2 Medium supports the growth of better than Buffered Enrichment Broth, Demi-Fraser broth, and Modified University of Vermont Broth, as indicated by the faster growth rate of the organism. When used as an enrichment medium in a method comparison study of ice cream, the results showed that R2 Medium-enriched samples tested with the Roka Detection Assay gave an equivalent performance compared with the 24 h FDA-BAM reference method at 10 and 18 h post-enrichment for . The results from this study indicate that the new R2 Medium and the highly sensitive Roka Detection Assay allowed for the rapid detection of species in ice cream in 13 h. The Roka Detection Assay, in conjunction with a new media formulation (R2 Medium), allowed for the early detection of in ice cream and may be applied in other food matrixes and environmental samples.