SCIENTIFIC experts were last night trying to find the source of salmonella contamination which has led six major food chains to withdraw houmous products from their shelves.
Tesco and Sainsbury's, as well as Co-op, Somerfield and Waitrose, removed items after salmonella was found in some Marks & Spencer products.
Iceland-based manufacturer Bakkavor pulled products from the five other chains after M&S recalled two own
-brand houmous products on Thursday when salmonella was found during routine tests.
Bakkavor makes own-brand houmous products in the UK for all six retailers.
A spokeswoman for the firm said: "We are continuing work on our investigation following our voluntary product recall.
"This includes thorough testing and examination of our raw materials, the finished product and our manufacturing processes.
"This work is being carried out in conjunction with a number of independent scientific laboratories."
The recall affects own-brand pots of houmous and flavoured houmous sold at each of the six chains.
Bakkavor is urging customers to return the products to stores for a full refund.
A statement on the firm's website says: "A number of batches of houmous manufactured by Bakkavor Group in the UK have been recalled.
"During routine testing, salmonella was discovered in two varieties of houmous manufactured in one of the group's factories.
"The cause is related to a raw material. This incident will have no material effect on Bakkavor Group's earnings."
The firm would not reveal exactly how many pots of houmous were being withdrawn but reports estimated it at tens of thousands.
The firm has said it has not received any complaints about the houmous, which is being recalled as a precautionary measure.
Bakkavor apologised to customers for any inconvenience and asked them to call its care line on 0800 023 2960 for further information.
M&S earlier withdrew all unaffected houmous products from its stores as an "extreme precaution" while an investigation into the contamination was being carried out.
