The deadline for retailers to remove products containing the illegal additive Sudan 1 from their shelves passed on Thursday.
Some types of crisps are among the products affected
Any shopkeepers continuing to sell them face prosecution.
With 474 products known to be affected by the potentially cancer-causing dye, food manufacturers and retailers are trying to count the costs of the contamination.
Northern Foods, based in Hull, recalled its Rover's Return Lamb Hotpot and halted production for a day after it was found to contain contaminated Worcester sauce.
The firm has now found an alternative source and production is back to normal.
The total cost of recalling products is hard to quantify, with large manufacturers still calculating their losses and assessing how their expenses will be met.
Northern Foods public relations manager Tony Smith said his firm would not lose out financially, though the disruption has been "significant" - it would pass the costs on to the firm which supplied the contaminated ingredient.
The cost of stopping production would be covered by insurers.
However, he said the whole food industry might have to absorb some of the costs of the Sudan 1 contamination, to avoid sending insurance premiums rocketing.
Harder to calculate is the cost of the damage to consumer confidence, in individual brands and in the ready-meal industry as a whole.
Mr Smith said: "It's about the reputation and the safety of the consumer. There's still a lot of work behind the scenes to make sure this doesn't happen again.
"The question is, 'How has it happened, where's this batch come from?'
"We hope one day we'll find out how it can be stopped."
He said the food industry would welcome new regulations to ensure unsafe ingredients were not allowed to slip through the net in future.
The Food Standards Agency says it is planning a critical review to see if any further measures could be taken to by companies to ensure food products are safe.
The major supermarket chains had to remove hundreds of products from sale.
Supermarkets had to stop production of any products which might have been affected and find new suppliers of the ingredient.
But as most had systems already in place to deal with this kind of problem, they may not have been hit as hard as smaller manufacturers.
Sainsbury's spokeswoman Cheryl Kuczynski said the firm had withdrawn 50 own-brand products, including more than 30 ready-meals.
She said: "Probably supermarkets have been able to deal with this more easily than smaller retailers.
"The systems swung into action and we were able to clear the shelves by Wednesday."
She said Sainsbury's had managed to reformulate its ready-meal recipes, re-start production, and had them back on supermarket shelves by 23 February.
But it will take longer before products sold in jars and tins are replaced.
For small retailers, the main problem is accessing up-to-date information about which products are affected.
The Association of Convenience Stores (ASC) says not all small retailers have access to the internet, where the list of products affected has been kept updated on the Food Standards Agency website.
But they should have been kept informed by their suppliers, by trading standards officers or by the ASC itself.
A spokesman said: "The main issue for us has been getting the information out to them as quickly as possible.
However, as the majority of affected products were from supermarket own-brand ranges, he said small retailers would find themselves having to remove only one or two products from sale.
Suppliers were taking back the affected products and refunding retailers, so they would not lose out financially.
He added: "The number of different products affected by the this product recall makes it a big issue and one we have to take seriously.
"But product recalls, not necessarily for health reasons, happen quite regularly. So the systems are quite familiar to retailers."