Top organic food brands want the Environmental Protection Agency to enforce more stringent truck emission standards to clean up their delivery fleets and lower the cost of their products.

"We believe that stronger cost-effective standards make economic and environmental sense," the organic food companies said in a letter sent Friday to the EPA and the Department of Transportation. "The availability of fuel-efficient trucks is critical to reducing our carbon footprints as well as our fuel costs and ultimately cost-savings to the consumer."

The standards they are referring to are EPA's Phase II rules for heavy-duty big rig trucks to lower greenhouse gas emissions and improve fuel efficiency. The standards are in the queue to be finalized before the end of summer and are a key part of President Obama's climate change agenda and goal of meeting U.S. obligations under a global emission deal penned last year in Paris.

The companies want the agencies to increase the target for reducing big-rig fuel consumption by 4 percentage points, while reducing the amount of time companies would have to get there. It's not clear if trucking firms, which are subject to the regulation, will go for the idea, especially after EPA already negotiated the cuts with them before proposing the standards last year.

Last year's proposed standard seeks a 36 percent cut in fuel consumption by 2027 to drive better fuel efficiency while cutting greenhouse gas emissions. Many scientists blame the emissions for causing the Earth's temperature to rise, resulting in more catastrophic weather events. The organic food companies want the target changed to a 40 percent reduction by 2025.

They argue that it is technologically feasible to hit their target and that the agencies should adopt it before making the truck rules final.

The dozen companies that signed the letter include: General Mills; Amy's Kitchen; Annie's Inc.; Ben & Jerry's; Clif Bar & Co.; Happy Family; Late July Organic Snacks; Lundberg Family Farms; National Co+op Grocers; Organic Valley; Patagonia Inc.; and Stonyfield Farm Inc.

The letter was organized by the multi-sector business group Ceres, which represents private companies on environmental and sustainability issues.