Mrs Rich, who was the National Party candidate for Dunedin North, and retired from politics at the general election after more than eight years in office, will start in March.
It is well known that Mrs Rich (40) retired from the party to spend more time with her family and she said the new job would allow her to do that.
Her four children and husband, Andy, would move to Wellington, with Mr Rich commuting to Dunedin "probably weekly" to oversee the running of his scaffolding business, SkyBoys.
The food and grocery council represents the manufacturers and suppliers behind many of New Zealand's food, beverage and grocery brands; oversees an industry which makes $15 billion in retail sales and $3.5 billion in exports; and employs 148,000 people.
Mrs Rich said the role as chief executive of the council, taking over from Brenda Cutress who was in the job for 20 years, was the ideal transition from politics, as it was "part business and part politics".
The contacts she had made over the years as an MP would come into use.
"I saw it as a real opportunity to combine all the aspects of a job I was looking for," she said.
Before entering politics, Mrs Rich worked for the Foundation for Research, Science and Technology; the Ministry of Agriculture and Forestry; and Alliance Textiles.
She was also general manager for international agribusiness company Silverstream Ltd.
Council chairman Peter McClure said, in a statement: "We believe that she will have the competence, drive and political understanding to take over."
However, Mrs Rich said the move to Wellington would not be permanent, as the family was "very sad to be leaving Dunedin".
"I'm going to put my heart and soul into this role, but I have a special affinity for Dunedin, particularly the Taieri. I am hard-wired to the South."
