TV commercials, newspaper adverts and a radio PR campaign will all be launched within the next two weeks. The strategy is part of a wider recovery programme that the company planned last year.
Product packs have also been redesigned and new premium products, such as a deli range, have just been launched.
Commercial director Bart Dalla Mura said criticisms of the company had "cut to the core", and that the strategy would focus on core consumers rather than media commentators.
"There are a whole lot of people writing about our business who have never bought our products, never have, never will. But there's a whole lot of people who want to buy our products because they are value for money, nutritious, convenient and easy and they shouldn't feel guilty about it."
Matthew Pullen, marketing director, said: "We have got to restore consumer confidence and brand reputation. That's key in the next couple of months."