Best Practices

Detection of anaerobic microorganisms

When you examine a sample for the presence of anaerobic beer spoilers, all working steps during the whole analysis must be focused on avoiding any contact of oxygen with the sample. Ideally, the sample is put into the incubation vessel direct at the place of sampling, followed by immediate incubation in a non-oxygen atmosphere.

The ideal sample processing always has to be adapted to the sample type.

Swabs

FastOrange B Ready-to-Use Tubes are ideal for simple sampling.

  • It is absolutely necessary to moisten the swab with medium before using it for swabbing the sampling area.
  • The sampling area is wiped with the wet swab applying a light and steady pressure.
  • The swab is put into the reagent tube with medium immediately after swabbing, and the tube is closed tightly.
  • The tube with the swab is incubated at 25-27 °C.
  • Optional: Before or after sampling, the tube can be filled up to the brim with FastOrange B Bouillon or a dilution thereof.

Liquid samples

FastOrange B Bouillon is the liquid medium for the detection of anaerobic beer spoilers. Besides turbidity, they often produce their characteristic bad smell and a color change, too.

  • First aliquot FastOrange B Bouillon into the sampling vessel (chose size according to sample volume).
  • Add sample into the vessel direct at the place of sampling, try to fill in as much as possible – foaming is not a problem, just leave the foam in the vessel.
  • Close the sampling vessel and carry it to the lab.
  • Incubate vessel at 25-27 °C, do not close lid tightly.

Membrane filtration

Membrane filtration for the detection of anaerobic microorganisms is only possible with special equipment and therefore not recommended for a standard lab. If equipment for anaerobic membrane filtration is available, filtered samples are enriched on FastOrange B Agar plates.

  • Preparation: Prepare FastOrange B Agar plates and pre incubate them at least 8 hours before use in an anaerobic jar or cabinet.
  • Take liquid sample and transport it into the lab under oxygen free conditions.
  • During sample filtration, flush the filter with sterile nitrogen or CO2.
  • Put filter onto the previously anaerobically incubated Agar plate and incubate immediately in anaerobic jar or cabinet.
  • Alternatively: Work in an anaerobic work bench.