Concerns have been raised about the different amounts of cash spent providing school meals for pupils.
In Aberdeenshire in 2010-11, the council spent just £1.68 for each school lunch provided, figures uncovered by the Greens show. That compares with an average £2.83 across Scotland for that year.
Argyll and Bute Council spent £4.01 per meal, the most of all the mainland authorities. Spending was higher on the islands - it cost Shetland Isles Council £5.29 for each meal provided, the highest amount anywhere in Scotland. Councils spent a total of around £151 million in 2010-11 providing school meals.
The figures were revealed by Minister for Learning Alasdair Allan in response to a parliamentary question from Green MSP Alison Johnstone. She said: "It is understandable island authorities face higher costs but the difference across the mainland is a concern. We need to strive for a consistent standard."
Last month it emerged that a frozen burger found in the kitchen of Cumbernauld High School, North Lanarkshire contained horse DNA. North Lanarkshire Council said the burger was supplied by Brakes Group. The discovery led to local authorities across Scotland being advised to "place a hold" on frozen beefburgers.
Ms Johnstone, a Lothian MSP, said: "Providing high-quality, locally sourced, nutritionally balanced meals in schools has never been more important. Amid the horse meat scandal, warnings about processed meats shortening lives and rocketing levels of diabetes, we cannot put a gloss on this issue any longer.
She said Scottish ministers have still to learn from schoolgirl blogger Martha Payne who "quite fairly documented the poor choices children are often offered". Martha made headlines across the world last year when her local council banned her from posting photographs of her school dinners online.
The Greens highlighted the differing cost of providing school meals as education ministers joined pupils in marking the first International School Meals Day. Education Secretary Mike Russell, Children's Minister Aileen Campbell and Mr Allan visited schools to highlight their work promoting healthy eating. The day aims to raise awareness of good nutrition and foster healthy eating habits in children both in school and at home.
Mr Russell, who visited Tighnabruaich Primary School in Argyll, said: "It is encouraging to see that take-up of school meals in Scotland has been rising since 2008 and continues to do so. The quality of our school meals is high overall, and our whole school approach is internationally recognised."
Mr Russell, together with Rural Affairs Secretary Richard Lochhead and Local Government Minister Derek Mackay, met councils and parents earlier this week to discuss how the quality and standards of school meals can be improved. The Education Secretary said: "We will do this through a refresh of our Hungry for Success initiative, and the Scottish Government is keen to encourage more fresh and locally sourced produce in school meals."