The e-mails are flying at a furious pace. Duncan Hines, the last major maker of pareve (meaning dairy-free and meat-free) baking products, is adding dried milk to its cake mixes, making them off-limits after a meat meal for those who keep kosher.

Kosher cake-eaters are not sitting idly though. They’ve launched an email campaign asking Duncan Hines to reconsider its decision. An e-mail campaign – however spirited – may seem futile, but similar tactics proved successful a couple of years ago when Kraft threatened to use milk chocolate in Stella D’oro cookies. Kosher eaters cried foul, and Kraft eventually backed away from its plan.

Kelley Maggs, a vice president and general counsel at Duncan Hines’s parent company in Mountain Lakes, N.J., Pinnacle Foods Group, says he has talked to more than a few unhappy kosher-keeping cake-eaters.

“We’ve communicated with a number of individuals and organizations who prefer that we keep a nondairy cake mix,” Mr. Maggs said.

Still, Mr. Maggs said Duncan Hines is sticking to its decision. He said the dairy-free cake mixes were made at the same plant where products that include dairy ingredients are being made, and there are safety concerns about dairy ingredients somehow making their way into nondairy products.

“We’re always open to adding new line extensions,” he said. “If there’s enough interest, in the future there may be some desire to have one or two nondairy cake mixes, but right now we’re not able to do that.”

Duncan Hines announced last month it was going dairy, but it didn’t take long before the news had panicked some in the kosher community. On the Kosher Blog, for example, someone calling herself Sara said she tried to buy whatever nondairy Duncan Hines mixes she could find, but her effort was thwarted. “We went to the grocery store yesterday to stock up and it was too late – looks like our rabbi’s wife cleared out the shelves.”

Meanwhile, the news has yet to hit many kosher supermarkets. The owner of the kosher market Akiva Grocery and Poultry in Brooklyn, Morgi Kbariti, wasn’t aware that Duncan Hines was switching to dairy cake mixes. He still has the nondairy mixes on his shelves. He said he sells three or four boxes a day, but doesn’t expect the dairy version will sell as well.

“They’re popular now because they’re nondairy,” Mr. Kbariti said. “I won’t be able to sell them if they become dairy, and I don’t think anyone knows that they are becoming dairy.”

Duncan Hines isn’t the only maker of nondairy cake mixes. Many health-food stores stock nondairy mixes from the likes of Pamela’s Products and Cherrybrook Kitchen. The key difference, however, is price and availability. A box of Duncan Hines’s Deluxe Moist mix likely costs between $2 and $2.75, depending on the store, while a bag of Pamela’s Products chocolate cake mix may be priced upward of $5.

For many kosher bakers, Duncan Hines is the mix of choice. Just ask Evelyn Rothfeld, one of many recreational bakers who will no longer be able to use Duncan Hines for a quick dessert fix. As the mother of two, mother-in-law to two, and grandmother to one, she says she’s been a longtime fan of Duncan Hines cake mixes, as well as their chocolate-chip cookie and brownie mixes. They’ve helped boost her reputation as a baker, Mrs. Rothfeld says.

“I get a lot of compliments on my baking,” she said. “I usually don’t tell people it’s from a box. You can take Duncan Hines cake mixes and add things, make something a little more fancy, but it’s still pareve. I guess all that’s a thing of the past. I suppose I’ll be doing a lot more baking from scratch now.”

For the more ambitious, it isn’t an impossible feat to bake a nondairy cake from scratch. It’s not as easy as a Duncan Hines mix, but it’s doable, the owner of a kosher bakery, Orwasher’s Bakery on East 78th Street, Abram Orwasher, said.

“You just have to substitute ingredients,” Mr. Orwasher said. “If the recipe calls for butter, you use margarine. Sometimes pareve cakes are lacking though. There are limitations. You can’t, for example, have whipped cream. You can make a good pareve apple pie, but you certainly can’t make a cheesecake.”