Workplace Minister Amanda Rishworth says she doesn't accept claims food prices will rise as a result of Labor's migration overhaul. Tony Burke announced the federal government will extend a ballot scheme for backpackers in their second and third years. The National Farmers Federation has warned the government's migration shake-up will lead to higher food prices come Christmas. Rishworth told ABC News Breakfast the agriculture sector should use the PALM scheme, which she says has been underutilised. "Backpackers are still going to be able to come to Australia, let's be really clear about this," Rishworth says. "There are programs such as…