SACRAMENTO, Calif. — The debate over Proposition 37 — a California ballot initiative to label genetically modified foods — is heating up as the election draws near.

While only a handful of crops are genetically modified — including some squash, papaya, sweet corn, soy, cotton and sugar beets (a GE apple and salmon might soon be approved) — GM ingredients are widely used in processed foods, according to Stacy Malkan, media director for the Yes on Prop 37 — California Right to Know Campaign, of which Nature’s Path, Dr. Bronner’s Magic Soaps and Organic Valley are sponsors.

“About 70% of processed foods on supermarket shelves now contain genetically modified ingredients,” Malkan said.

GM ingredients may be pervasive, but Malkan noted that given a long grace period, compliance would be seamless. “It’s a business-friendly law that gives companies 18 months to change their packaging,” she said.

“They can put additional information on existing labels — either on the front or back, wherever they choose.”

Thomas Hiltachk, attorney for the opposing campaign: No on 37, Stop the Deceptive Food Labeling Scheme, of which the Grocery Manufacturers Association is a chief sponsor, contends that under the mandate, the burden borne by retailers would be substantial since they’d be left vulnerable to so-called “shakedown lawsuits” brought by private attorneys without proof of harm. “The retailer is first in line to a litigation assault,” Hiltachk said.

He explained that in the case of a product that should be labeled but isn’t, a retailer who is sued could in turn sue the manufacturer for not including the GE label. But retailers would also be vulnerable under a second scenario with products not identified as “produced with genetic engineering” simply because they haven’t been produced this way.

Read more: GM Foods Unlikely to Concern Wal-Mart Shoppers

While the item’s manufacturer should be able to provide affidavits attesting to the product’s non-GMO status, retailers would be exposed to liability if the paperwork were misplaced.

“If at any time the paperwork chain is broken due to negligence or just a mistake, then there is potential exposure,” Hiltachk said. “Just imagine the thousands of products in the store and the only protection is a piece of paper.”

To minimize exposure, Hiltachk recommends collecting sworn statements for all unlabeled processed foods — and not just those containing ingredients for which there are GM options — since any item with multiple ingredients might be hard to verify.

The Yes on Prop 37 Campaign counters that the ballot initiative was designed so that there can be no frivolous suits, like the ones Hiltachk describes, associated with the labeling law.

“They’re absolutely misleading their constituents when they say that,” said Steven Hoffman, managing partner of the Compass Natural public relations firm and part of the California Right to Know Campaign.

Groups Disagree About Prop 37's Effect on Consumers

The groups also disagree about how the proposition would affect consumers.

Last week, the No on 37 campaign distributed a study by Northridge Environmental Management Consultants that found that re-labeling, repackaging or remaking thousands of grocery products with higher priced ingredients would increase the cost of food sold by as much as $5.2 billion a year, adding $350 to $400 to the typical family’s grocery bill.

“Prop 37 will drive up grocery costs for California families, while providing absolutely no benefits,” said Jamie Johansson, an olive farmer and second vice president of the California Farm Bureau Federation.

“It’s a hidden food tax, and it comes at the worst possible time to add more financial burden on consumers and food producers, when we already face an economic downturn and a severe drought.”

Read more: California GMO Bill Is Top Priority for GMA

Malkan noted that it’s unclear how the reformulation of products might play out if the measure passes, but Californians will ultimately decide with their wallets.

“Some [suppliers] may choose to just label in California, and some will move away. But the bottom line is that consumers should decide because they’re the ones who are buying and eating the food,” Malkan said.

If passed by voters, beginning July 1, 2014, in-store bins of produce like papaya from Hawaii would bear the descriptor “genetically engineered” and packages of processed foods with GM ingredients identified with the words: “partially produced with genetic engineering.” “May be partially produced with genetic engineering” is another option.

Products that are certified organic would be exempt from labeling, as would alcoholic beverages; foods certified by an independent organization such as the Non-GMO Project; foods sold for immediate consumption; meat, eggs and milk derived from an animal that’s not been genetically engineered, even if it was fed or injected with GE food or a drug produced through genetic engineering; and product for which a producer can provide affidavits from suppliers attesting to its non-GMO status.

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