A McDonald's worker has advised customers to keep their receipts to ensure their feast is fresh.

McDonald's trick

McDonald's trick

Kamran Adan, who has claimed he worked in the fast food chain, has encouraged people to politely ask for their receipts after ordering a take-away, as it is believed the piece of paper can guarantee they receive a meal that has not been waiting around to get cold.

The man alerted customers to the hack in a post shared on Quora.com, which read: ''Basically between 12-2 and 5pm-7pm workers have to be extra careful because that is when gapbusters (mystery shoppers), who are paid, visit McDonald's restaurants and rate their experience. This then goes to the overall store rating and every store manager will do everything to ensure this rating is as positive as possible.

''It is easy to spot a gapbuster because they always ask for a receipt (so they can get their food costs reimbursed by the company employing them). So, if you ask for a receipt in that time everyone will be immediately alert that you could be a potential gapbuster and they'll make sure to serve you the freshest burger and fries and give you priority over everyone else (sic).''

And it is rumoured this tip is mostly carried out by mystery shoppers, who rate the quality of food and the service they received during their visit, who ask for proof of purchase so they can reclaim their expense.