The move comes as annual shoplifting offences soared past 500,000 in the 12 months to last September, while numerous videos on social media showed offenders taking items from shelves without be stopped by police.
If the pilot scheme works for both staff and customers, bosses may be tempted for a roll it out across the country.
Greggs said in a statement: “This is one of a number of initiatives we are trialling across a very small number of shops which are exposed to higher levels of anti-social behaviour.
“Customers can expect to see our full range of great value and tasty Greggs favourites available from behind the counter.”
Despite being hit by a shoplifting crimewave, Greggs continues to expand across the UK, with plans to introduce vending machines to allow customers to quickly grab their favourite treats.
Other high-street brands have also taken action to target the rise in shoplifting, with Costa Coffee and Pret A Manger hiring bouncers to guard food and drink at selected stores.
Marks & Spencer has issued staff with body-worn camera, while Sainsbury’s brought in checkout cameras last year to record customers who failed to scan items.
Lucy Whing, crime policy lead at the British Retail Consortium, told the Sun: “Criminals and organised gangs are targeting products that are easy to move and sell on.
“Ultimately such theft is not a victimless crime, it pushes up the prices for honest shoppers.”