TwistDx to launch red snapper authenticity test

DNA detection specialist TwistDx is gearing up to launch a new test to authenticate red snapper, which is one of the fish most prone to falsification in the US supply chain.

The new kit is based on TwistDx's proprietary TwistAmp DNA amplification technology and can be used for species authentication "directly from fish material" and without any need for lab equipment, instrumentation or specialist know-how, according to the Cambridge, UK-based firm.

The test can identify whether a fish sample is genuine in around 40 minutes, according to the company.

The TwistAmp range was first introduced in 2009 and is the first DNA amplification product to make use of recombinase polymerase amplification (RPA) which is says has greater sensitivity than traditional polymerase chain reaction (PCR) techniques.

"Red snapper (Lutjanus campechanus) is a highly prized food fish caught commercially along the Atlantic coast of North America and Mexico," says TwistDx.

"Frequently, lesser species of fish are mislabelled and sold as substitutes in place of the valuable genuine red snapper," it adds.

For example, a sampling study carried out on behalf of Consumer Reports magazine and published in December 2011 found that 12 of 22 samples of red snapper bought at retail stores and restaurants in New York, New Jersey and Connecticut were not the claimed species.

In fact, none of the 22 samples could be definitively identified as red snapper, although eight were possible matches according to DNA testing, and those that turned out not be genuine were either other kinds of snapper or rockfish species such as ocean perch.

It is very difficult to determine where species substitution actually takes place in the supply chain, as fish tend to pass through the hands of many players "from hook to cook," according to the report.

Red snapper typically costs about $20 for an average size fish, while inferior species can retail for less than half that amount.