A group of Essex County mayors travels to Parliament Hill today to meet with federal Agriculture Minister Gerry Ritz.

The mayors will try to convince him to kill plans to deregulate food packaging sizes.

The visit comes weeks after the minister came to Essex County to speak with food processing stakeholders in the region.

He met privately with officials of local food processing operations.

The federal government is proposing to deregulate package sizes.

There's a concern the move will put Ontario food processors at a disadvantage to their American counterparts and cause massive job losses.

Kingsville Mayor Nelson Santos says the message from the companies is clear and blunt.

"They've told the minister directly and in black and white, without a level playing field it is basically closing the door on their business and they will relocate south of the border. They will go away from their investment in Canada," Santos said.

Santos will be joined by the mayors of Leamington and Tecumseh in Ottawa on Tuesday afternoon.

Food processors have joined the fight with a "Keep food jobs in Canada" movement.

They say if food production leaves the country, local farmers will lose out on market opportunities.

The mayors want to discuss the potential far-reaching economic and social impacts of the proposed deregulation of food packaging.

Leamington Mayor John Paterson said company officials have made it clear: if the new measures are approved, local plants will be shut down.

"A couple of the companies said, 'If you do this, my business closes, period. There's no ifs ands or buts. We're done,'" Paterson claimed. "So they made it very clear to the minister what could happen."

The mayors say plants run by Heinz, Bonduelle and Sun-Brite in their towns are all at stake.

The ministry said that while package sizes “do not affect food safety in any way," the regulations fall under the Canadian Food Inspection Agency (CFIA). Streamlined sizes will free up inspectors to focus on allergy labelling and food inspection elsewhere the ministry said.