The revised standards, which for the first time apply to new academies and free schools and those that were established before 2010, are designed to make it easier for school cooks to create imaginative, flexible and nutritious meals.
They replace those introduced between 2006 and 2009, which required schools to use a special computer programme to analyse the nutritional content of every menu.
While academies and free schools founded between 2010 and June 2014 remain exempt, the Department for Education said they are being encouraged to sign up to the standards voluntarily.
Despite this, the Local Government Association (LGA) is continuing to call for the school meal standards to be mandatory for all-state funded schools. Its call is being backed by the National Union of Teachers (NUT).
The new rules, which include guidance about portion sizes for primary and secondary children, place greater limits on fried food and those high in salt, along with restrictions on foods that include pastry.
There is also a greater emphasis on wholegrain carbohydrates, requiring schools to provide one or more starchy wholegrain once a week.
Under the new rules, meals must include one or more portions of vegetables or salad as an accompaniment every day, and at least three different fruits and three different vegetables each week.
Schools must also limit fruit juice servings and promote drinking water.
Details of the new school food standards were unveiled by ministers last June, following a review of school meals by the founders of the Leon food chain John Vincent and Henry Dimbleby.
Schools minister David Laws said, ‘These new food standards will ensure that nutritious, tasty meals can be enjoyed by all children who choose a school lunch. Providing healthy school food boosts children’s health and education. It gives them the fuel they need to concentrate inside and outside the classroom and establishes healthy eating habits for life.’
At the same time as the introduction of the revised food standards, a new Change4Life campaign has been launched to encourage parents to cut down the amount of sugar their children consume.
The campaign, being led by Public Health England, recommends four sugar swaps for parents to chose from, they include swapping sugary cereal for plain cereal for breakfast, and giving children low-fat lower sugar yoghurt as opposed to ice-cream for pudding.
It comes after findings from a survey on the views of Netmums users on sugar, revealed that nearly half (47 per cent) think their family has too much sugar in their diets, and two-thirds (67 per cent) are worried about the amount of sugar their children consume.