Catering staff at an Essex school are taking the fingerprints of pupils at lunchtime to ensure they get the meals their parents want them to eat.
Pupils queue at the fingerprint point before collecting lunch
Parents pay in advance, often over the internet, at the Deanes School in Benfleet to avoid issues linked with children having cash.
The schools said the system also helped it promote healthy eating.
Children can no longer buy sweets or fizzy drinks and the risk of losing their money is reduced, it added.
Head teacher Jan Atkinson said: "As a specialist Sports College with over 1,000 pupils we have had a healthy living focus for the past 18-months.
"The implementation of cashless catering further enables us to ensure that the students receive nutritious healthy meals.
"A significant number of parents are now also using a web service to make secure online payments to schools by credit and debit card.
"This allows parents to put money in their children's account and be sure that it is spent in the school dining room and not elsewhere."
In addition, parents can get a report showing what their child has bought.
"This has been found to be very reassuring for parents whose children have allergies, childhood diabetes or similar conditions where their diet needs careful monitoring," Mrs Atkinson added.
At the point of payment the pupil places their finger on the fingertip scanner, and once successfully verified their account is debited.
The head teacher said the school was now looking at other ways of using the technology, such as school travel.