Dear Recyclebank: Can I recycle the bags from my dry, dog and cat food? –Sue M.

Dear Sue: It can be a challenge to be a pet lover and to be environmentally responsible (a case in point being kitty litter). When it comes to recycling pet-food bags, it often comes down to what the bag is made of, and what your curbside hauler, or a local drop-off program, accepts.

We consulted Diane Herndon, senior manager of sustainability for Purina, to get some input on whether pet food bags are recyclable. She says the packaging used for dry pet food is made up of a variety of materials, including polypropylene, paperboard, and mixed plastics (polyester and polyethylene).

Purina and other pet food manufacturers are increasingly turning to flexible plastic materials like polypropylene for pet-food bags because it is more durable than paper, it’s lightweight for shipping, and it keeps the food fresher. Unfortunately, most curbside recycling programs don’t accept this material because many Material Recovery Facilities (MRF) can’t sort it. Pet food that comes in a paper bag might not be recyclable either, if it’s been reinforced with a plastic coating — as one municipal recycling facility puts it: If you can’t tear it, it’s probably not recyclable. Purina has a recycling guide on its site where you can check the recyclability of various food- and pet-product packages.

Terracycle has a recycling program to collect and recycle Wellness and Open Farm pet-food bags. For these programs — or if you find another recycling program that will accept your plastic pet-food bags — just make sure the bags are empty, and if you wash them (not necessary, says Herndon), they should be dried.

While it can be a challenge to recycle plastic pet-food bags right now, it might not always be. Purina is working with other product and packaging manufacturers in a research collaborative called Materials Recovery for the Future (MRFF).

“Member companies and organizations, like Purina, are working with community recyclers to find a way, through separation technologies, new equipment installation and process reconfigurations, to cost-effectively separate and make a market out of recycling flexible plastic resin,” says Herndon.

An early study shows that today’s sorting equipment could be optimized to accommodate flexible plastic packaging, which would create an entirely new stream of recoverable materials. According to the MRFF website, the organization is currently looking for an (MRF) to participate in a pilot program.

There’s good news when it comes to other pet care products, though: Herndon says the steel-aluminum cans for wet pet food, as well as litter jugs, and the box and tray packaging for can variety packs, are all recyclable.