SACRAMENTO, Calif. » Major biotech companies and manufacturers of household food products, including Campbell Soup, General Mills and Coca-Cola, have pumped almost $12 million into the campaign to defeat Proposition 37, the California ballot initiative to require labels for genetically engineered crops and processed food products.

Most of the funds were raised in recent weeks. New contributions on file with the California secretary of state’s office show that members of the Coalition Against the Deceptive Food Labeling Scheme contributed $9.98 million since the close of the Jan. 1-to-June 30 reporting period.

The large cash infusion swelled the No-on-37 group’s total campaign kitty to $11.9 million.

Meanwhile, proponents reported recent big contributions totaling $756,000 as of Friday. That’s in addition to the $2 million reported during the first half of the year. The Yes-on-37 campaign, backing what it calls the California Right to Know initiative, already has spent a substantial amount of money to qualify the measure for the ballot by gathering about 1 million signatures from registered voters.

The campaign is backed mainly by organic farmers, health food retailers, makers of processed organic foods and consumer groups.

Campaign spokeswoman Stacy Malkan said she was surprised that big agriculture and grocery manufacturers have raised so much money so quickly.

"It clearly shows they are going to start running television advertisements soon," she said. "The fact is they are nervous about being behind in the polls."

A recent statewide poll by Pepperdine University and the California Business Roundtable showed the Yes campaign had a commanding lead with 69.4 percent of respondents in support. Opponents accounted for only 21.8 percent with 8.9 percent undecided. The Internet poll of 873 likely voters was released Aug. 2.

Kathy Fairbanks, a No-on-37 spokes­woman, would not say when her campaign would begin running television spots. "We are committed to defeating this measure," she said. "It’s seriously flawed. It will cost consumers more money and will jeopardize employers."

Farmers, food processors, biotech companies and many scientists contend that genetically modified foods derived from plants that have been altered at the cellular level are identical to non-genetically modified crops. They accuse backers of Proposition 37 of trying to scare consumers into eating more expensive organic products.

Proposition 37 advocates counter that they’re not trying to ban so-called GMO foods, but just want to give consumers more information about what they are buying to eat.