Sodexho and Scolarest are to stop bidding for school catering contracts worth less than 55p a meal.
In separate moves, the UK's two largest contract caterers have both set the same lower limit for all future deals.
Mike Bailey, chief executive of Scolarest parent company Compass, said: "Setting the limit is not the end of the debate but it's a bloody good start. You've got to aim high - if you don't ask, you don't get."
A spokeswoman for the group added: "More money buys fresher produce and pays staff to stay in the kitchen longer and spend more time cooking."
Stephen Thorns, director of Sodexho's education division, said: "We realised that there was a gap between expectations and the cost of ingredients. Contract extensions won't necessarily be included in that 55p figure - they will be judged on their individual merits."
The public announcements by the two catering giants come within a day of each other and follow the Government's recently declared plan for higher nutritional standards in schools.
They also come at the halfway point of Channel 4's series Jamie's School Dinners, in which celebrity chef Jamie Oliver tries to raise the standard of food in schools across the country.
The Local Authority Caterers Association, which represents public-sector caterers, believes a broader rethink rather than a minimum-spend pledge is required.
Chairman Neil Porter said that contract specifications needed to be altered in line with requirements to deliver a higher food quality. "There needs to be a greater understanding of the issues involved, such as increased staff hours, higher wages, training and kitchen improvements."
Meanwhile, the Durham school featured in last week's Jamie's School Dinners has opted out of its Scolarest contract, along