The GM debate has re-emerged in the UK in the last couple of weeks with the news four major supermarket operators will allow their suppliers to use GM feed for poultry and eggs. 

For the food industry, this is an awkward moment for the issue to return to the spotlight. The UK has arguably only just begun to stabilise after the seismic shock of the horsemeat scandal.

Can comparisons be drawn between these two stories, and how might the rawness created by the horsemeat scandal affect the latest phase of the long-running GM debate? 

Clearly there are distinctions. The former is essentially a fraud issue and did not, more by luck perhaps, represent a risk to health. Fraud is not the issue with GM, though conspiracy theories abound, while public health most certainly is the pivotal factor.

However, what is certainly a common thread is the question of trust. Campaigners may characterise the major supermarket retailers  - albeit to varying degrees - as malign, manipulative corporate giants exploiting a credulous consumer base, but however devious they may or may not be, they crave and most certainly rely upon the widespread trust of their customers. Their family-orientated marketing virtually pleads for it.

And when something threatens that trust, or when they have to undertake a change of policy which could undermine it, they mobilise well-oiled PR machines.

The packed news agenda of the last two weeks has undoubtedly helped the supermarkets. The death of Margaret Thatcher and the Boston bombs, particularly coming the week before the London Marathon, followed by footballer Luis Suárez deciding that Branislav Ivanovic was safe to eat, all but relegated the issue to media chicken feed.

The story will continue to smoulder, however, and may well flare up again suddenly. There is likely to be further media interest. With the change of policy announced first by Tesco, followed quickly by The Co-operative Group, Marks and Spencer and Sainsbury's, Waitrose is now the only UK supermarket chain stipulating all its suppliers of chicken and eggs use non-GM feed. Asda and Morrisons made the switch last year. 

All have claimed that it is increasingly difficult for their suppliers to source non-GM soy though campaigners say these claims are exaggerated and that retailers in other European countries are not experiencing the same problems. 

They also mention the difficulty of being able to guarantee that non-GM soy sold as such does not contain GM soy. It is perhaps slightly surprising any of the retailers highlights this particular aspect. One of the long-running concerns raised by anti-GM campaigners is the fear of contamination, that it is virtually impossible to carry on developing GM without it eventually contaminating conventional crops. The debate over GM crop trials centred on this issue.

Because of the volume of GM soy now being grown, the issue of contamination is extremely pertinent. However, Tesco presents it almost as if it should not, in itself, be a concern. "Because so much soya is modified and because of the way crops are planted, processed and transported, it is possible that non-GM soya crops contain low levels of GM soya," Tesco states. "The new DNA testing regime we have put in place has identified that the risk of finding GM material in non-GM feed is increasing." Does this really fit with a statement that is supposed to make us feel more secure about the idea of GM? 

So in the UK all eyes are on Waitrose which clearly feels, at least for now, that the ethical kudos in holding its position outweighs the logistical difficulties or cost implications it might create. 

Speaking to just-food, Peter Melchett, policy director at The Soil Association, recalls the impact Iceland Foods holding a strong position on GM in the 1990s had on the other retailers, and believes if Waitrose retains its firm line and gives consumers an alternative, this could yet be a "game changer".

Linked to the issue of trust is another factor the GM issue has in common with horsemeat, namely the role of the Food Standards Agency (FSA).

The UK's official food safety body was at the centre of the horsemeat scandal, and the FSA is also the organisation the public is now relying upon for impartial and accurate advice on GM.

The fact that both sides of this debate are quoting the FSA underlines the centrality of the organisation's position, while also in itself being rather bemusing. 

The FSA says that "food from animals fed on authorised GM crops is considered to be as safe as food from animals fed on non-GM crops", and the retailers are keen to stress that the FSA endorses the safety of these foods.

However, Tesco adds the following: "The Food Standards Agency (FSA) is clear that functioning GM DNA from modified soya is not present in the meat of animals fed on it, nor in animal products such as eggs or milk. Genetic modification affects only the crop used in the feed." This is perhaps an interesting use of the word "clear".

The Soil Association says both Tesco and The Co-op are "misleading their customers" by claiming the GM feed will not be detectable in eggs, milk or chicken, and quotes an FSA tweet to support this.

In its most recent statement, the FSA says the following: "With improvements in detection techniques, it is possible that tiny amounts of GM plant DNA could be detected in products from animals fed on GM crops. However, there are no techniques currently available to consistently detect the presence of DNA fragments in animal products, such as meat, milk, eggs, where these animals have been fed GM feed."

Clearly, in reflecting the most recent scientific view and stating that some GM DNA might be detected in GM-fed animal products the FSA is covering its back. Particularly just after the horsemeat scandal, this organisation is not going to say anything unequivocally unless it is sure of its ground. 

However, this does not just underline the FSA's caginess. It also speaks to the nuanced nature of the scientific debate over GM. Since the GM issue first emerged in the 1990s, it has been characterised by claim and counter-claim by campaigners and GM proponents respectively, purportedly all supported by science.

For Dan Crossley, executive director of the Food Ethics Council, the polarisation on GM underlines the need for a mature debate.

While expressing concerns about the long-term sustainability of GM itself, Crossley pointedly adds: "We need a more sophisticated debate about our relationship with food. Rather than narrowly focusing on one technology that comes with a lot of baggage, we need instead to be more fleet of foot. Let's get beyond the paralysis of GM good or GM bad. Let's explore the range of possible options out there and what the most effective mix of solutions is to address the huge challenges we face in our food system. In doing that, we mustn't neglect the voices of marginal farmers and poor communities. We should be asking them what kind of agriculture they want and how they see the challenges they face."