U.S. confectionery giant Mars has ordered a full recall of a number of its most popular chocolate bars in the UK, and several other European nations.

Customers are warned not to eat any Mars or Snickers bars or Celebration boxes with best before dates from June 2016 to January 2017, as they may contain plastic.

The massive recall covers millions of products sold in 55 countries, including the UK, Germany, Spain and France, which are all made at Mars Inc's factory in the Netherlands.

Now, stop, choc: All Mars and Snickers bars with best before dates from June 2016 to January 2017 have been recalled in 55 countries, including Britain, Germany, France, Netherlands, Belgium, Italy and Spain

The recall initially covered products sold in Germany and the Netherlands, before being extended to Britain, Italy, Spain and France on Tuesday afternoon, as well as dozens of other countries.

The recall affected all Mars and Snickers products, Milky Way Minis and Miniatures as well as certain kinds of Celebrations confectionery boxes.

The concerned products will have best-before dates ranging from June 19, 2016 to January 8, 2017.

'As far as we know there are 55 countries involved,' Eline Bijveld, Mars corporate affairs coordinator for the Netherlands said Tuesday.

The recall 'only involves the products that are made in the Netherlands', at the Mars factory in the southern town of Veghel.

The recall initially covered products sold in Germany and the Netherlands, before being extended to Britain, Italy, Spain and France on Tuesday afternoon, as well as dozens of other countries

The recall only involves products made at the Mars factory in Veghel, The Netherlands (pictured)

The move comes after a customer found a red piece of plastic in a Snickers bar bought on January 8 in Germany.

After he complained to Mars, the plastic was traced back to Veghel which determined that it came from a protective cover used in the plant's manufacturing process.

'We are currently investigating exactly what's happened, but we cannot be sure that this red piece of plastic isn't in any other of our products from the same production line,' Bijveld said.

So the food giant has decided in a 'voluntary' fashion and 'out of precaution' to issue the recall which covers mostly European nations including Holland, Germany, France and Britain.

It also spreads further abroad to some countries like Sri Lanka and Vietnam, but does not extend to the United States, she said.

One way to diet: Mars Inc said the recall affected all Mars and Snickers products, Milky Way Minis and Miniatures as well as certain kinds of Celebrations confectionery boxes.

It is the first time that Mars has had to recall products made at its Veghel factory, opened in 1963, which employs some 1,200 people.

However, it is not the first time Mars has recalled products over customers finding pieces of plastic in their chocolate.

In 2007, Mars UK recalled packs of Maltesers and Revels after some customers found small pieces of rubber in the sweets.

At the time, Mars said 'an isolated incident' on the production line at their factory in Slough, Berkshire, was to blame for the contamination.

A spokeswoman said: 'Five consumers contacted us about the problem, which resulted from an isolated maintenance incident on one of the production lines, which was identified and repaired.'