Schools have been advised by the government to consider buying longer shelf life food products to “minimise the effect” of any supply chain disruption because of Brexit.

In updated guidance today, schools were reminded the new UK Border Operating Model will apply to all goods entering the UK from 11pm on December 31.

The guidance states it is “important for all schools, FE colleges and local authorities to prepare for potential changes to food supplies so they can minimise the effect on pupils and young people in their care”.

This includes contacting suppliers to check whether they will need to change meals or ingredients, make changes to school menus and that their secondary suppliers “are prepared”, something schools were first warned about in guidance last year.

The latest guidance adds while the school food standards allow changes to school meals, it reminds leaders they will still have to meet nutritional standards, provide free meals to some pupils and manage special dietary needs.

But, in what appears to be the updated section of the guidance, schools are warned they may need to “consider whether changes are necessary”, including “ordering longer shelf life products during this period, such as frozen foods or foods that can be safely stored at room temperature”.

Other changes include “varying the timing and number of deliveries to allow for transport delays” and “being as flexible as possible on delivery times during the day”.

It was reported last month the government had plans for up to 10 inland sites to cope with congestion and border checks post-Brexit.

But the government has been warned some ports will find it “impossible” to carry out checks on fresh food. Time is also ticking on the government and the European Union agreeing a deal to avoid a no-deal Brexit.

Paul Whiteman, general secretary of school leaders’ union NAHT, told the Guardian: “Let’s be frank: there’s almost nothing that any school can meaningfully do to mitigate the effects of Brexit, as they have no control over what will happen after 1 January.

“So, it is entirely wrong for the government to offload responsibility for a successful Brexit outcome onto schools and other public services.”