Researchers in China develop rapid meat adulteration test

A team of scientists in China have developed a new DNA test for species adulteration in meat that can give a verdict in around 30 minutes.

The researchers – from Nanjing Agricultural University and Zhejiang Academy of Agricultural Sciences – say the technique can detect multiple species including duck, chicken, cow, sheep and pig, and is easier, quicker, and requires less equipment than other techniques such as polymerase chain reaction (PCR) testing.

Their approach is to combine recombinase polymerase amplification (RPA) – a rapid alternative to PCR developed by UK biotech TwistDx Ltd that competes with other rapid amplification systems such as LAMP, NEAR and HDA – with the nucleic acid stain SYBR green I produced by Life Technologies’ Molecular Probes subsidiary to visualise the results.

Detecting animal species in meat products is important as substitution can be a problem for people with food allergies as well as for those who don’t eat certain species on religious grounds. The researchers write in the journal Food Chemistry that verification of food labelling is becoming more important “to ensure food safety and trade fair in both local and international markets.”

They note that RPA is becoming increasingly common in diagnostics to detect viruses or bacteria, but there are “few reports applying it to meat adulteration detection.” The technique can be carried out at 37 degrees Centigrade in a water bath and unlike PCR doesn’t require the use of a relatively expensive thermal cycler to amplify the DNA.

The technique also has advantages over other visualisation approaches such as agarose gel electrophoresis, “which still needs several complex instruments and sophisticated operations,” say the researchers.

RPA and SYBY green I was able to detect 1 per cent pork adulteration in mutton or beef, and could also differentiate species in boiled, microwaved, pressure-cooked or fried meat samples.

“These results highlight an attractive characteristic of RPA as rapid species identification method [and] could serve as an alternative to the traditional methods to detect adulterants in meat rapidly and conveniently,” conclude the researchers.

Meanwhile, another study published in PLOS One has highlighted the low levels of trust in China about the authenticity and safety of food that is produced domestically.

“Consistent with the literature, consumer concerns were noted to have been perpetuated in the wake of multiple food scandals reported in the Chinese media, the most notable being the 2008 melamine … scandal,” say the authors from Newcastle University in the UK.

“Despite considerable efforts to improve the integrity of the domestic food supply chain in China, Chinese consumers have low levels of trust in food that is domestically produced and perceive food that has been produced in China to be of inferior quality and safety to food produced in other countries.”

The researchers say regulators and food producers should consider helping Chinese consumers to identify authentic food products – for which they are prepared to pay a premium - through activities such as tighter regulations, greater enforcement activity by the authorities, and product testing and transparent communications from industry.

“Communications should serve to reassure consumers about the safety of products, in addition to the authenticity cues provided on labels,” concludes the report.

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