With their sweet flavor and low acidity, San Marzano tomatoes — grown in the volcanic soil of Italy’s Sarno valley near Mount Vesuvius — are widely considered the finest tomatoes to use in sauces.

West Deptford-based Cento Fine Foods, by accounts America’s largest seller of canned San Marzano tomatoes, is facing accusations in two federal lawsuits that its San Marzano-labeled products are not the real thing and that consumers are overpaying for them. San Marzanos are more than twice as expensive as conventional canned tomatoes.

The issue comes down to certification. Just as France fiercely defends the use of “champagne” only for sparkling wines produced in that region, Italy issues legal certifications, including Denominazione d’Origine Protetta (or Protected Designation of Origin), to verify the authenticity of some food products.

Consorzio San Marzano says true San Marzano tomatoes have a DOP symbol and its certification on the label. The consortium’s president in 2017 contended that only 5 percent of San Marzano tomatoes sold in the United States were genuine.

Cento’s labels read “San Marzano" but do not have a DOP symbol.

Cento, in a recent statement, said it “refutes all of the inaccurate and wrongful claims in the complaint and is astounded by the lack of factual information therein.” It also says: “Our fields and farmers are audited by an independent third party in Italy who assures that the tomatoes are grown in the rich fertile soil of Sarnese-Nocerino at the base of Mount Vesuvius in Campagna.”

Cento explained on its website that after its crop was approved and certified authentic in 2010, a new organization was appointed in Italy to govern its labels.

“After months of delay in their response, we were notified that our label no longer conformed to their requirements,” the company said. “Due to the unreasonable nature of the new label requirements, Cento decided to remove the DOP seals from our label: however, they remain certified San Marzano tomatoes and continue to follow the high-quality standards. Our Cento Certified San Marzano Tomatoes are certified by the largest third-party certifying body in the European Union, Agri-Cert.”

One suit, filed in U.S. District Court in New York in February, alleges fraud, contending that Agri-Cert merely supplies the San Marzano seeds and “possibly certifies whether the [products] are organic, as opposed to certifying the growing and quality of the final product.” The suit also asserts: “It is implausible that defendant can sell more San Marzano tomatoes than all other companies in the U.S. combined, and do so by cultivating only four fields.”

The most recent suit was filed by three plaintiffs May 14 in U.S. District Court in Oakland, Calif. Melissa Weiner, their attorney, told TV station KGO in a statement that the lawsuit "seeks to reimburse consumers for the price they paid for tomatoes that are, as alleged, not certified or true San Marzano tomatoes and halt Cento’s allegedly deceptive marketing and labeling of the tomatoes.”

In a statement to The Inquirer, Daniel S. Tyler of the law firm Amin Talati Upadhye described the suits as frivolous and wrote: “These complaints are littered with demonstrable inaccuracies that are easily disproven by documented facts. We look forward to aggressively defending both actions and clearing Cento’s good name. Motions to dismiss are on file and forthcoming. ... Cento stands 100% behind its products and we hope the media reports on the defeat of these baseless claims as thoroughly as it has reported on hollow allegations.”