Food manufacturers and retailers have been urged to do more to protect the integrity of their raw materials supply chains.
Speaking at the City Food Lecture, Sir John Krebs, chairman of the Food Standards Agency, said the current checking systems were good but he felt they could be better.
"I think there may be room for food manufacturers and retailers to be more proactive in ensuring that the materials they use meet the required standards.
"In this way, unacceptable levels of contaminants can be kept out of the food supply without the need for the recalls and withdrawals that cause [the industry] so much concern and cost. This applies as much to home produced foods as it does to imported foods."
In particular, Sir John warned that enlargement of the EU would open up the UK to food processing plants that did not comply with European standards. And while these plants were upgraded or closed, compliant and non-compliant products would have to be segregated.
In addition,he said, there would be new external borders over which illegal imports could slip through. "Regulators will play their part, but industry will also have to be vigilant in checking its sources to ensure safety and borders are upheld."
Sir John said there was an obvious upside to the industry placing even more emphasis on the security of its supply chain. "Which has the biggest impact on consumer confidence: pre-emptive vigilance by the industry or the removal of foods from shelves after the consumer has eaten them?"
In a wide-ranging speech delivered at the City Food Lecture which is sponsored by Sainsbury Sir John highlighted the other issues topping the FSA's agenda.
These included the need to work with industry to continue reducing salt in food and the agency's ongoing concerns over misleading food labels.
But Sir John also flagged up issues surrounding food assurance schemes.
He said in principle these were a force for good. But he warned that consumers had little understanding of what "assurance" meant, and there was a danger that some people were being "hoodwinked".
"If assurance schemes are to play a significant role in raising standards and building consumer confidence, they must be committed to the principles of honesty, transparency and independence," Sir John said.
But he added: "I am pleased to see that some producers are aware of these needs and are attempting to meet them."