The stability of micro-organisms preserved in LENTICULE discs, demonstrated by repeat sample distributions of the EQUAL Scheme for Indicator Organisms (water microbiology)

Aims: To demonstrate the stability of microorganisms preserved in LENTICULE discs, employed by the EQUAL Scheme for Indicator Organisms. Methods and Results: Five sample batches containing several indicator organism parameters were each despatched in two separate distributions at intervals of up to 24 months apart. A comparison of participants' median counts and bar charts of their cumulated results was then made. Conclusions: The results demonstrated that LENTICULE discs provided a remarkably stable preparation format for the maintenance of viable organisms in reproducible numbers. Significance and Impact of the Study: Complex mixtures of organisms can be maintained in stable numbers for extended periods of time at a freezer temperature of -20 degrees C and satisfactorily transported without the requirement for cold chain conditions.