The Prince of Wales said he was "virtually brought up on Weetabix" during a visit to the factory.
Prince Charles met staff on a tour of the factory
Prince Charles was visiting the plant in Burton Latimer, Northants, on Tuesday to present the firm with the Queen's Award for Enterprise.
Chairman Sir Richard George gave the prince a tour of the factory where he saw production of some the 65m biscuits produced each week.
The site produces biscuits for distribution to 80 countries.
Presenting the award to Sir Richard, the prince commented: "I always enjoy enormously opportunities to visit family companies... and nothing could give me greater pleasure than to visit Weetabix.
"I was virtually brought up on Weetabix - and look at the result.
"It is interesting, you start having two or three and as you get older you shrink down. But I have always wanted to see how they are made."
Weetabix, which holds three Royal Warrants and three Queen's Awards for Export, received the new honour for the rise in export sales across Europe.
Prince Charles added: "It has been a particular pleasure to meet people who have worked for the company for 20 years and some who are second generation employees.
"It is something that is enormously special and speaks volumes for the
The firm received the award for enterprise in international trade for
overseeing a 45% growth in exports in the last six years.
Weetabix's international commercial manager, Andy Harris, said overseas sales
for Britain's biggest cereal manufacturer now made up 18% of the group's sales.
"The consumption of cereals in the UK is seven kilos per head but in
Europe it is about a third of that so there is a huge potential for growth.
"The whole European health thing is growing, people on the continent are
moving into breakfast cereals."
The Weetabix brand is the top-selling breakfast cereal in Britain and also produces Alpen and Weeto cereal bars.