Glycerol, an EU-approved additive used to lower the sugar content of drinks, gives ice drinks their slushy effect and is generally considered safe.

However, concerns remain about its effects on children aged 10 and under when the additive is used at high levels in slushy ice drinks.

These drinks are commonly sold through slushy ice machines in various outlets, as syrup concentrates that can be prepared at home, as pre-packaged products in supermarkets and retail stores, and online.

Updating its voluntary guidelines, the FSAI said the industry must only use a “safe quantity of glycerol” when producing slushy ice drink concentrates.

"Manufacturers of prepackaged slush ice drinks and make-at-home syrup concentrates containing glycerol should carry a warning on the pack in keeping with the FSAI advice," it said. 

"Retailers selling unpackaged slush ice drinks containing glycerol should display permanent point-of-sale warnings stating: 'this product contains glycerol and is not recommended for children aged ten and under'," the FSAI added. 

FSAI chief executive Greg Dempsey said slushy ice drinks are placed at the top shelf of the Department of Health’s Healthy Eating Guidelines food pyramid, “meaning that they are not part of a healthy, balanced diet”.

"For the rest of the population, these slush drinks should therefore be limited and only consumed in moderation as a treat," he said. 

"Consumption of glycerol-containing slush ice drinks by children aged ten and under could cause headaches, nausea and vomiting. On rare occasions, it could potentially lead to severe symptoms such as shock, hypoglycaemia (low blood sugar) and loss of consciousness," Mr Dempsey added.