Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2009 Sep 30;135(1):75-80.
doi: 10.1016/j.ijfoodmicro.2009.07.003. Epub 2009 Jul 12.

Differential fluorescent staining of Listeria monocytogenes and a whey food soil for quantitative analysis of surface hygiene

Affiliations

Differential fluorescent staining of Listeria monocytogenes and a whey food soil for quantitative analysis of surface hygiene

Kathryn A Whitehead et al. Int J Food Microbiol. .

Abstract

The accurate monitoring of surface cleanliness in terms of bacterial contamination is usually carried out using methods such as plate counts or replica plating. However these methods take at least eighteen hours to obtain results and do not determine the presence or amount of residual organic material on a surface, which may interfere with cleaning and disinfection. This work describes the application of fluorescent stains to cells (Listeria monocytogenes) and food soil (solubilized whey) to optimize a dual staining method that can be used in the quantitative analysis of surface cleanability. Seven different stains were tested at a range of concentrations (0.3%-0.001 mg/ml) and application methods. The best stain combination for differential staining of L. monocytogenes and whey food soil was 0.1 mg/ml rhodamine B with 0.1 g/ml DAPI. Differential staining of the cells and soil occurred regardless of the application method. This method has been successfully used to demonstrate the hygienic status of surfaces in an industrial situation. This novel work enables quantitative assessment of soils and cells on surfaces.

PubMed Disclaimer

Publication types

LinkOut - more resources