Testing for Dekkera bruxellensis can be done using the Techne Prime Pro 48 qPCR (polymerase chain reaction) system with the Techne qPCR test ‘Dekkera bruxellensis 26S ribosomal RNA’.
Flavour-spoiling phenolic compounds from this yeast lead to undesirable aromas, known as ‘Brett’ taints, associated with aromas of barnyard, burnt plastic, wet animal and horse-sweat.
This can lead to large economic losses in the wine industry, said the firm.
Spoilage monitoring difficulties
Jim Bratherton, product manager at Bibby Scientific, said the monitoring of Brettanomyces/Dekkera yeasts remains difficult for most winemakers.
“Traditional methods employed by vineyards to identify spoilage yeasts in wine have involved cell culture of the yeast in a selective media known as EBB medium,” he told FoodQualityNews.
“This contains commercial grape juice added to ethanol, malt extract and yeast extract with chloramphenicol to limit mould and bacterial contamination.
“There are alternative cell culture mediums, such as DBDM (Dekkera /Brettanomyces differential medium) which also utilise ethanol as a carbon source.”
The yeast is also found in traditional Belgian beers as it is native to the Belgian Senne valley near Brussels. Its genome size ranges from under 20 to over 30 mega base pairs (Mb).
The microorganism lives on the skins of fruit and plays a key role in production of Belgian Lambic style beers.
However, traditional test methods take a long time to get results with the differential media tests taking one to two weeks to perform.
Higher sensitivity and faster
Bratherton said with qPCR, sensitivity is extremely high, as theoretically down to one copy of Dekkera /Brettanomyces genome per sample can be identified.
“qPCR is much quicker (approximately one hour test) and 100% specific for the spoilage organism even in very low quantities,” he told us.
“The decision can therefore be taken much quicker to ship the product to market. The Techne qPCR instrument is one of the lowest price on the market (£12,000) with kits costing £3.50 per test.
“That is more expensive than traditional methods, but consider the cost of storage and delay in shipment for two weeks until traditional methods provide results. If there is a problem with the test then [it can be] another two weeks to re-test.”
The Techne qPCR Kit for D. bruxellensis is designed for the in vitro quantification of D. bruxellensis genomes.
It is comprised of primers and probe sequences that have 100% homology with a range of D. bruxellensis sequences based on bioinformatics analyses.
‘Untapped’ food and drink market
Bratherton said food and drink was a ‘relatively untapped market’ for Bibby Scientific but there are synergies between Techne products and Bibby’s other brands; Stuart, Jenway and Electrothermal.
Techne has manufactured PCR instrumentation since 1987, specialising in PCR instrumentation, electing to design machines that are universally fitting with respect to consumables and chemistry.
Bratherton said recent advances in qPCR reagent technology have enabled Techne to realise the goal of also supplying reagents and offering a complete system to the market.
“Real time PCR reagents are traditionally supplied in liquid form, aliquoted into tubes, frozen and shipped in dry ice containers,” he said.
“The novelty with the Techne Prime Pro qPCR reagents is that components are lyophilised (freeze dried) and simply supplied with a tube of sterile water for re-suspension later.
“Before re-suspension, the kits are stable at ambient temperature for transportation and storage purposes. Freezer storage (-20°C) is not required until reagents are rehydrated.”
The elimination of cold logistics enabled Bibby to integrate reagents into a business specialising in equipment, he said.
“Real time PCR kits have always been supplied with lyophilised DNA, the real innovation from Techne is to also provide the master mix component lyophilised, thus eliminating the need for freezers and dry ice.”