The marketing budget is expected to run for two years and includes both creative and PR.
The Swiss client used the AAR to handle the pitch, involving an undisclosed number of agencies for the UK end of the business.
The company is attempting to expand beyond its European heartland and now also has a presence in Turkey, Egypt, Saudi Arabia, USA and Japan.
BLM chief executive Steve Booth said: "It was a highly competitive pitch against two of the multi-nationals. It's a damned good win."
BLM's other food clients include Domino's Pizza, Tryton Foods, who produce the Aunt Bessie's line and Young's Bluecrest.
Hero has a presence in UK supermarkets through its Super Cook range of baking products.