Britain’s foremost kashrut authority has said that it will reconsider the certification of Green & Black’s organic dark chocolate after the confectioner announced that it will now label the product as containing milk.

Although there is no change to the recipe, a recent audit revealed that traces of milk residue could be found on the manufacturing equipment used to make it, because milk chocolates were made using the same production line.

The company will now list milk as one of the ingredients on the packing of its organic dark chocolate bars.

Rabbi Jeremy Conway, director of the London Beth Din’s Kashrut Division, said: “In light of this new notice from Green & Black’s, we will be re-examining the kosher status of this product.”

Georgie Tarn and Tracey Fine, authors of The Jewish Princess Cookbook, said: “Don’t panic. There are so many varieties of delicious dark chocolate. As long as it has a minimum of 70 per cent cocoa solids to get that chocolate hit, why not experiment?”

However, Rabbi Conway added that he was not convinced that the chocolate would be struck off the list of kosher products.

He said: “It is not uncommon for parev items to be manufactured on the same production line as dairy products.

“This does not necessarily affect its halachic status as parev since the potential cross-contamination is such a tiny percentage.

“For this reason, the kashrut guide’s confectionary section highlights clearly that ‘the designation parev does not guarantee that the product is suitable for those with dairy or lactose intolerance’.”

Dominic Lowe, managing director of Green & Black’s, said: “We are committed to an open policy and we have always been transparent about what goes into making our organic chocolate.

“We want to keep customers informed about the potential inclusion of milk ingredients — albeit in low levels — and provide a clearer warning than we have done previously.”