The embattled chief executive brushed off speculation about his future despite no sign that his £1 billion plans are bearing fruit.
Tesco has been forced to change the packaging on its cartons of orange juice after a schoolboy spotted a grammatical error.
Supermarket Tesco have been given the go ahead to screen the advert, despite complaints it may encourage animal cruelty.
Sainsbury's commercial director Mike Coupe said it was "time to take a stand" on the row over the Tesco Price Promise, which the supermarket believes does not offer a fair comparison.
Mr Coupe said:
"Tesco says that whether, for example, a product is Fairtrade or MSC [Marine Stewardship Council] certified is just a 'minor part' of a customer's considerations - especially for value products. We disagree.
More than ever, customers want to let their values guide them and in price-matching its products with ours, Tesco is - when it sees fit - choosing to ignore factors such as ethical or provenance certification or even country of origin.
The Tesco Price Promise is a money-back pledge that compares the price of goods in a shopper's trolley at the checkout with prices at rival supermarkets Asda, Sainsbury's and Morrisons.
Any difference on comparable products is then refunded in the form of a Tesco voucher worth up to £10.
Sainsbury's believes the pledge misleads consumers because it does not make fair comparisons by, for example, matching products such as its Everyday Value Tea, which is not Fairtrade, with Sainsbury's basics tea, which is.
It added the pledge is also misleading on its basics water, which comes from a spring in Yorkshire, and is compared with Tesco's Everyday Value water, which Sainsbury's claims starts at the mains supply.
Sainsbury's is stepping up its fight against Tesco's Price Promise campaign in a long-running row over comparisons between the two firm's products.
Britain's third-biggest supermarket chain is to take its battle into the courtroom, by requesting a judicial review against a ruling by the Advertising Standards Authority (ASA) that rejected its complaint over the Tesco pledge.
The move comes after Sainsbury's lost an appeal against the ASA decision earlier this month, when a report by the watchdog's independent reviewer Sir Hayden Philips backed the ASA findings.
Mike Coupe, Sainsbury's commercial director, said it was "time to take a stand" on behalf of customers to ensure shopping decisions are not just based on price, but also factors such as ethics and provenance.
The campaign group Feeding the 5000 has welcomed Tesco's decision to report figures on food waste, but believes this is only the first step.
Campaigner Domnika Jarosz told ITV News:
We are pleased that Tesco has decided to report their food waste and have it audited by third parties, but we see this as a first step.
Supermarkets are responsible for far more than what they waste [in their supermarkets and distribution centres] because they control a large part of the supply chain.
– Domnika Jarosz, feeding the 5000
Their strict cosmetic standards - which reject straight bananas and cracked cauliflowers, for example - mean there is a significant amount of waste before products even reach the shelf.
As a result of pressure from consumers, supermarkets and retailers are starting to compete with each other to see who can lead the way on food waste. We hope other supermarkets will start measuring their food waste.
Tesco's commercial director of group food, Matt Simister, said the growing world population is going to put increasing pressure on the supply of food.
Mr Simister continued, "Really that means one of two things - we can either be more productive end to end, or we can waste less."
Oxfam said the amount of food that is wasted when one billion people go to bed hungry at night "is nothing short of a scandal."
Oxfam's head of economic justice policy Hannah Stoddart said: "It is a damning indictment of a food system that places greater importance on corporate profits than ensuring everyone has enough to eat.
"It's great news that the biggest supermarket in Britain is taking tentative steps to tackle the problem, but we need urgent action like greater regulation and investment from governments worldwide to fix the system."
Following Tesco's discovery that the average family spends £700 a year on food that is thrown away, we asked ITV News viewers, "How much food do you waste every week?"
- Dawn Robson says, "I never throw away food, I write a list of meals I'm making that week and only buy what I need ... Those who throw food away must be rich and have money to burn."
- Jenny Collins comments, "Maybe they should make bagged salad in smaller portions? I quite regularly throw away half a bag."
- Steven Jefferies says he throws away "loads" of food, adding, "Being single it is more expensive to buy individual items than it is pre-packed."
The Waste and Resources Action Programme (Wrap) said collaborative action on food waste is "essential" if it is to be successfully reduced.
Wrap director Richard Swannell said: "We welcome Tesco's approach to tackling food waste across their whole supply chain, and by identifying the hot spots they can tackle these areas effectively.
"Food waste is a global issue and collaborative action is essential if we are to successfully reduce food waste and reap the financial and environmental benefits of doing so."