Species of the Alicyclobacillus spp. genus are large, immobile, spore-forming, thermophilic bacteria that occur almost anywhere in the environment. The spores of Alicyclobacillus may find their way into production through contaminated fruit during harvest. They are tolerant to high pasteurizing temperatures and low pH-values, which is why they easily proliferate in juice. There are 18 known species, with Alicyclobacillus acidoterrestris being the most significant. In the event of contamination with A. acidoterrestris, specific metabolites form that produce a repulsive taste and odour but are not hazardous to health. The product itself remains visually flawless, neither gas nor discolourations form. Even small amounts of the bacteria can lead to product spoilage, which is why the beverage industry’s in-house specifications demand a zero-tolerance approach. Alicyclobacillus spp. contamination affects almost all non-alcoholic beverages, e.g. apple, pear, orange, tomato and grape juice.
What analytical methods does ifp Institut für Produktqualität offer?
Cultures are grown according to IFU (International Federation of Fruit Juice Producers) method no. 12 and take up to 10 days incl. confirmation in the event of a positive result. Analysis can be done quantitatively for filterable samples or qualitatively for non-filterable samples. The disadvantage of this method is that a positive result provides no information about which species of the genus was found.
ifp Institut für Produktqualität offers analysis using its own Duplex-PCR system, which is a molecular biological rapid method for the detection of Alicyclobacillus. It produces qualitative results within one to two days. This method also provides information about whether the genus found is Alicyclobacillus spp. or specifically Alicyclobacillus acidoterrestris.