Whether in relation to environmental or social issues, sustainability debates generally abound with conspiracy theories, suspicion and exposés.

The blogosphere throbs constantly with accusations of corporate skulduggery, with varying degrees of veracity or exaggeration, concerning contentious topics such as the use of GM, food additives, animal stewardship and deforestation. Highly suspicious of corporate PR and greenwash, the campaign community scrutinises what food companies are doing more closely than ever, prepared to 'name and shame' without hesitation.

So, it is ironic to say the least that this year one of the biggest scandals to hit the European food sector for years, namely 'horsegate', was not foreshadowed by intense speculation or rumour.

The first exposure came about not as the result of covert filming by a watchful pressure group but from the work of the Food Safety Authority of Ireland (FSAI)

While concerns had been voiced over the scaling down of the UK Food Standards Agency's remit and the risks posed by over-complex supply chains, this was an instance where criminal conspiracy was rife, and yet there had been a conspicuous absence of 'conspiracy theorising'. Campaigners were, in general, as wise after the event as the industry and regulators.

The horsemeat scandal was without doubt the biggest public interest story to hit the food industry in 2013. In an interview with just-food in March, Professor Chris Elliott of Queen's University Belfast, who was later selected by the UK government to head up an official enquiry into the scandal, said that it was only by chance that the widespread criminality uncovered in the food supply chain had not represented a danger to human health.

Professor Elliott's review concluded in December that the UK food industry was "too vulnerable" to fraud and work was needed to tackle "food crime".

It is perhaps equally ironic the horsemeat scandal should have occurred at a time when food companies are placing increased scrutiny on the overall sustainability of their supply chains, notably with regard to in agricultural commodities such as palm oil, soy and cocoa.

This year has seen some notable developments as food companies have sought collectively or individually to address sustainability issues in their supply chains. 

Perhaps the most ambitious individual company undertaking was General Mills' pledge in September to "sustainably source" ten "priority" ingredients, including wheat, dairy and cocoa, by 2020.

Earlier in the year, fifteen major farmed salmon producers, representing around 70% of the global industry, combined to form the Global Salmon Initiative (GSI), aimed at raising sustainability standards in their sector, addressing concerns over biosecurity and feed sourcing.

GM has continued to be a hotly debated issue during 2013, not least in the US during the build-up to the vote in Washington State on Initiative 522, which would have required products containing GM ingredients to be labelled as such. The vote was defeated by 54.8% to 45.2%, with a huge amount of industry lobbying for a 'no' vote.

On the other side of the Atlantic, UK Environment Secretary Owen Paterson said in June that GM was a "safe, proven and beneficial innovation" the Government and industry had a "duty" to explore.

The focus food companies are placing on sustainable sourcing is reflected in the sheer number of news stories during 2013 relating to the sustainability of agricultural supply chains. 

This year saw US chocolate producer Hershey launch its 21st Century Cocoa Plan, while the year closed with an announcement by Lindt & Sprungli that it would be expanding its support programme for farmers in Ghana.

In May, Spanish company Natra committed to sourcing 100% certified cocoa by 2020, while in the same month, Nestle said it would be using only UTZ-certified cocoa in its Nestle Crunch brand in the US.

During the year, Archer Daniels Midland, Barry Callebaut, Blommer, and US retailer Kroger all announced enhanced commitments regarding the sustainable sourcing of palm oil.

Meanwhile, joint commitments to source sustainable palm oil were announced by industry groups in Germany and France in September.

However, without doubt the most notable development of the year regarding palm oil came in December when Wilmar International, which controls around 45% of the global production of and trade in palm oil, pledged to "ensure that both Wilmar's own plantations and companies from which it sources will only provide products that are free from links to deforestation".

Unilever, with which Wilmar signed a memorandum of understanding detailing its new commitments, said in November that all the palm oil it uses will be traceable to known sources by the end of next year.

There have also been significant developments at the consumer end of the value chain during 2013. At the beginning of 2013, just-food forecast that food waste would be a prevailing sustainability issue this year, and so it proved.

A report from the UK-based Institution of Mechanical Engineers (IME) in January, which suggested that as much as 50% of food produced globally was either lost or wasted, gained global media coverage and the issue was seldom far away from the headlines.

Later in January, the UN Food & Agriculture Organisation (FAO), in collaboration with civil society partners, launched the 'Think. Eat. Save. Reduce Your Footprint' campaign

In May, 45 UK food and drink manufacturers and retailers, including all major grocers, signed up to the third phase of The Courtauld Commitment waste reduction programme, first launched in 2005.

This was followed in October by a public declaration on food waste by the UK's largest food retailer, Tesco, including a commitment to change its promotional policy as part of its drive to cut food waste, an announcement which also attracted considerable media coverage.

In addition to reducing food waste and loss in the supply chain, food companies have a key role to play in helping to change consumer behaviour, and in that context a consumer campaign launched by Unilever in November to try to "motivate people to live sustainably" was another noteworthy development.

The balance between consumer, government and industry responsibility is also a recurring theme in debates over dietary health, not least in the debate over whether foods containing high levels of added sugar or saturated fat should be subject to additional taxation. The nutrient tax debate resurfaced in October this year when the Mexican Senate approved a tax on high-calorie foods.

While the case for nutrient taxes as a means of reducing obesity levels remains unproven, there is widespread support for front-of-pack nutritional labelling as a means of improving diets and reducing consumption of nutrients of concern such as saturated fat and sugar. The precise form such labelling should take for best effect, however, has been a far more contentious subject.

This year saw an important breakthrough in the UK when the government officially launched a uniform hybrid front-of-pack (FOP) nutritional labelling system incorporating traffic light colours and "reference intakes", formerly guideline daily amounts.

Under current EU law, the government can only recommend rather than mandate a system but the voluntary scheme is being backed by all the major food retailers and some major food manufacturers which were originally not in favour of using traffic light colours. However, a significant proportion of food manufacturers in the UK have yet to commit to the new scheme.

While health campaigners generally welcomed the support food retailers and manufacturers had given the government's new FOP scheme, commitments made in October by a raft of companies under the government's Public Health Responsibility Deal (PHRD) to reduce saturated fat levels in foods won few plaudits with campaigners. In general, health campaigners remain extremely sceptical of the Responsibility Deal as a mechanism either for changing corporate behaviour or addressing public health issues relating to diet and food.