Lesson 7 - Microorganism Detection and Control SAQ

** Your brewery wishes to reduce the time taken to detect beer spoiling bacteria. Which test would you recommend and why?

Response:

Most commercial rapid detection technologies have centred around polymerase chain reaction or PCR. Subsequently, bench top PCR analysers are now available.

You may wish to purchase a rapid test PCR analyser for your brewery for the following reasons:

1. Your brewery has a history of issues regarding contaminating microbes; test kits can be individualised to detect these.
2. It simultaneously detects and identifies species of beer spoilers (up to 20+ microorganisms), e.g. Brettanomyces, S. cerevisiae var. diastaticus, lactic acid bacteria, Megasphaera and Pectinatus.
3. A test kit measuring all 13 beer spoiling LAB can cost as little as $13 or $1 per organism tested.
4. The cost of the modern thermal cycler, real-time fluorescence-detecting machines has reduced to under $5,000.
5. PCRs provide a result from spoiled beer within three hours, whereas conventional methods can take up to seven (or more) days. This facilitates fast decision-making for contaminated beer, reducing the likelihood of product recall and subsequent negative consumer reactions.
6. PCR cuts enrichment time, if required from clear beer, to 24-48 h.
7. It can be used in yeast propagation prior to pitching the new yeast.
8. It is less labour intensive compared to traditional methods.
9. Modern systems are designed for easy use.
10. It costs less than traditional methods.
11. It has reliable and repeatable results.
12. PCR can be easily integrated into the brewery.

Despite these advantages, there are some downsides:

1. PCR does not quantify the concentration of contaminant.
2. The PCR does not tell us whether the organisms were alive or dead.
3. The cell detection limit may be insufficient to match the brewery’s specification limit.