While not seeming quite his usual self, Sir John presented an upbeat speech in which he reminded his trade colleagues about the positive role played by the industry in modern society - providing consumers with safe, affordable, quality food, as well as innovating to meet their changing needs.
However, he also made an aside about how they would be hearing more about food safety that afternoon. Nobody thought much about it - until later that day, when the recall of one million Cadbury chocolate bars was announced.
Food recalls rarely attract much attention. This one was different. By Saturday, the saga of the six-month delay between Cadbury first discovering the leak at its Marlbrook plant and the actual recall had hit the headlines and the BBC made the story its evening news lead. Cadbury was in the middle of complete PR meltdown, pondering what had gone wrong and what the long-term implications for the brand might be.
The shenanigans began in January, when Cadbury found a leak and sent contaminated chocolate for tests at a Health Protection Agency laboratory, where the rare montevideo strain of salmonella was identified. It was not until the HPA investigated a nationwide rise in the number of cases of the strain found in Cadbury's anonymous samples - there were 45 between March and June, compared with 14 in the same period last year - that the Food Standards Agency was alerted on 16 June.
The laboratory then contacted Cadbury and it officially informed the FSA of the possible contamination of seven of its lines.
Salmonella usually causes severe stomach upsets but can be fatal, and while there is no confirmed link between the reported cases and Cadbury's products, the brand is facing the prospect of long-term damage.
Besides losing short-term sales, the FSA has begun an investigation, there's the prospect of legal action from Herefordshire Trading Standards and the company has suspended its TV sponsorship of Coronation Street. Cadbury has also delayed the launch of a premium extension to Dairy Milk.
Some City brokers reckon that in the worst case scenario, Cadbury could take a £20m hit from the loss of consumer confidence.
Cadbury has defended its decision not to recall the products earlier, insisting that it followed all legal requirements, and it has said it is "absolutely satisfied" that its products are safe to eat. Indeed, at 0.3 cells of salmonella per 100g of chocolate crumb, the contamination was way below the company's own alert level of 10 cells per 100g. But Professor Hugh Pennington, president of the Society of General Microbiology, has said that the only safe level in chocolate is "zero", because the fat in chocolate preserves the salmonella from intestinal defences.
That sort of coverage has not helped the situation. Neither has ambiguity regarding the company's reaction to the situation, with praise for its openness and reassurance to consumers tempered by criticism over the delay.
It will be some weeks before Cadbury can assess the true extent of the damage to its profits and reputation. But warmer weather and the relative exclusiveness of some of the affected products may be on its side.
Paul Osborne, confectionery buyer for Hancocks C&C, says: "We haven't really noticed any change to sales of any other brands yet. We would expect dips at this time of year anyway because the weather's warmer. Cadbury has been quite lucky in one way. Most of the affected products don't have direct rivals, so there's no alternative for people to switch to."
Public affection for the Cadbury brand may yet see it through. David Arkwright, branding consultant at MEAT, says: "Brands such as Cadbury are like human beings and are forgiveable, but they have to earn that.
"I'm confident that Cadbury can be forgiven, but it would have to present itself as penitent and this must be done purposefully. I'm not sure they've done that as much as they ought, should and could, but it's a brand with huge equity and public affection and that can outweigh any momentary negative."
Paul Cousins, director of Catalyst marketing consultants, adds: "In the short term, the effects will be noticeable: some people are nervous. There'll be a short-term dip in sales, but in the long term I don't think it'll make much difference." n