Irn-Bru maker AG Barr, Tennent's and BrewDog say they are unaffected by a Europe-wide shortage of CO2.

The gas, which puts the fizz in drinks made by all three Scottish beverage makers, has become scarce as a result of production problems.

Scotland's largest abattoir, Quality Pork Limited, said it would be forced to suspend operations on Tuesday as a result.

It uses CO2-powered bolt guns to kill pigs ahead of slaughter.

Poultry producers have also been hit by the shortage, caused by extended seasonal shutdowns at five European CO2 producers.

Quality Pork Limited chief executive said he did not know when they would receive their next delivery.

"They're not telling us anything," he said. "We're pretty dismayed. The top priority is animal welfare.

"We will not have ourselves in a situation where the welfare is suffering."

A spokesman for AG Barr said the company had recently invested in extra CO2 storage and was not affected.

"We have multiple supplier agreements in place, but are monitoring the supply position and production schedules closely to protect customer supply as much as possible," they said.

Meanwhile, a spokesman for Tennent's makers C&C said: "Availability of C&C brands including Tennent's Lager and Magners Cider are currently unaffected."

BrewDog also said production had not been affected.

The CO2 shortage has been made worse by an extended break in production of ammonia by farms - one of the key sources of CO2.

The UK has been hit especially hard because only one major CO2 plant was operating earlier this week and imports from the continent have been affected by shutdowns in western Europe.