London’s largest kosher meat authority has banned the sale of ox and calf liver that has not been koshered beforehand.

Consumers can now buy only ready-koshered liver from London Board of Shechita shops. In guidance to butchers, the LBS explained that its religious authorities found today’s consumers less knowledgeable about koshering liver. “The reality has become that many customers of un-koshered liver have failed to kosher it correctly, or even at all, notwithstanding signage and instructions on the packaging.”

Liver has to be koshered with a flame or grill to make sure the blood runs off.

For many years, LBS meat and poultry has been sold ready-koshered to the public to “make life more convenient for the consumer”. The exception has been liver, where there was the option of the consumer koshering it themselves. The LBS is issuing clear instructions to “all those who will undertake the koshering that when they roast the liver on an open flame — due to the higher density of blood — they do not allow the liver to spoil by allowing it to roast for any longer than the period required by Jewish law”.

Any increase in the cost of liver to cover the additional work of koshering would be “marginal”.