Introduction:

The MicroSnap test platform is a rapid bioluminogenic method for detection and enumeration of specific organisms. MS2-COLIFORM & MS2-ECOLI tests are designed to specifically detect Coliform and Escherichia coli in less than 8 hours.

Tests consist of an Enrichment Device containing a specific growth medium and a Detection Device containing a bioluminogenic substrate in which the detection reaction is measured using a small portable luminometer. In Step 1 (enrichment), sample is incubated in growth media in order to increase the number of bacteria. As the number of bacteria increase, more of the diagnostic enzymes are created (beta-galactosidase and beta-glucuronidase), which are required for the bioluminogenic reaction.

Incubation time of sample is determined by the level of sensitivity required. After incubation, a small amount of sample is transferred to Detection Device. In Step 2, Detection Device is activated and incubated for 10 minutes.

At this time, a specific substrate reacts with diagnostic enzymes to produce light. Light is measured in a luminometer in seconds. Light output is directly proportional to initial starting inoculum.

MicroSnap Coliform and E. Coli is an excellent system for measuring microbial content in samples. It is able to measure surface, solid food, and liquid samples directly and give a calculated CFU and/or RLU value that can be directly compared to industry standards to food safety testing.

Problem:

Testing a cheese or other product of dairy fermentation causes abnormally high RLU readings in MicroSnap Coliform or E.Coli.

Solution:

This can be due to a number of issues due to the way the tested enzymes are expressed in the target organisms. These enzymes are not limited to coliforms and e. coli, and a number of other bacteria can also produce them, namely Lactobacilli or Lactococcus used in the manufacture and natural fermentation of dairy products into cheese. Some strains of Shigella Sonnei will also cause abnormally high readings and produce false positives.

The next step is to use 9ml MS-Enhanced EB broth as Step-1 instead of MS-CEC broth. Enhanced EB broth is a selective media, and it will inhibit the growth of background lactic acid bacteria. Enhanced EB broth was developed especially for such “problematic” dairy samples.

Additionally, Hygiena may be able to perform a validation study for you if you fulfill volume purchase criteria.