FDA warns San Francisco food maker over fermented cabbage sanitation gaps and mislabeled kvas

The U.S. Food and Drug Administration has warned a San Francisco food company that its refrigerated, ready-to-eat fermented cabbage was made under conditions that could allow dangerous bacteria to grow, and that three of its products carry mislabeled ingredients and nutrition information. The warning letter, addressed to RDM Express Inc. CEO Boris Dinerman, was made public this week and first reported by Food Safety News on Monday.

No recall has been announced and no illnesses have been linked to the company's products. A warning letter is a formal notice that FDA uses when it believes a company's practices violate federal law; it is often a step that precedes further enforcement if problems are not fixed.

What inspectors found

FDA investigators visited RDM Express Inc.'s facility on McKinnon Avenue in the Bayview neighborhood from February 18 through March 10, 2026, and issued a Form FDA 483 listing observed violations at the close of the inspection. According to the warning letter, the company had not submitted a written response to that report by the time the letter was sent.

The agency concluded that the company's Ready-to-Eat Fermented Cabbage, sold as Sour Cabbage, is adulterated under the Federal Food, Drug, and Cosmetic Act because it "may have been prepared or held under insanitary conditions," and cited the firm for failing to comply with federal preventive-controls requirements under the FSMA Preventive Controls for Human Food rule.

Specifically, FDA said the company's hazard analysis failed to adequately address environmental pathogens such as Listeria monocytogenes. Packaging took place in an open production room with no step afterward capable of killing bacteria, the letter states, and the company's cleaning records did not document monitoring, corrective actions or verification. Hygiene checklists reviewed by inspectors showed repeated "no" entries from October 2025 through February 2026 with no documented follow-up, and records were not being reviewed within the required seven working days. FDA also said the firm had no environmental monitoring program in place at all — a standard tool food makers use to catch contamination before it reaches a finished product.

The letter separately flagged the company's use of raw cranberries in a ready-to-eat product with no validated step to kill parasites or viruses such as Cyclospora, norovirus or hepatitis A, and said the company lacked a supply-chain verification program for that ingredient, as federal rules require.

A lab test raised the central question

At the heart of the letter is a single lab result. FDA collected a finished-product sample on February 25, 2026, and found a pH between 4.0 and 4.17, with a water activity of 0.98. The agency said that combination is not enough on its own to control pathogens: Listeria can survive at that pH level, and that water-activity reading is high enough to support bacterial growth.

Inspectors also found gaps in how the company measured acidity in the first place. Its standard procedure did not specify when pH should be checked relative to fermentation or cold storage, logs did not record measurement times, and samples were pulled from a single spot in large fermentation barrels rather than tested in a way that reflected the whole batch. The product was not retested for pH at the point of packaging, days after the initial reading, and the calibration of the testing meter lagged what the company's own procedure called for. FDA said the firm had not conducted a validation or challenge study to show its process reliably controls pathogens, and suggested that a consistent finished-product pH at or below 4.2 — paired with supporting science — would help close the gap.

Mislabeled kvas, pickles and cabbage

The letter also cites misbranding violations across three separate products:

• Russian Style Kvas Drink: an ingredient listed under a name other than its common or usual name; Russian-language text on the label that does not repeat all federally required information; and a Nutrition Facts panel missing added sugars, vitamin D and potassium.
• Sour Cabbage: net quantity declared in the wrong unit of measure for its product type, and no "distributed by" statement tied to the company's place of business.
• Half Sour Pickles: a net-quantity statement reading "32 FL OZ" without the required parenthetical "(1 qt)."

FDA added that both the kvas and pickle labels were also missing a street address, as required unless the company's address appears in a current city or telephone directory, and suggested the product name "Russian Style Kvas Drink" itself may not meet the FDA's common-name requirements.

Who's affected, and what's next

RDM Express's products are sold in the kind of small refrigerated cases found at Eastern European and Russian grocers rather than through national chains, and the company has little public footprint beyond its FDA inspection history, which includes at least one earlier warning letter in 2022. FDA's letter gives the company 15 working days from receipt to respond in writing with the specific corrections it has made or plans to make, supporting documentation, and a timeline for any work still underway. The agency warned that failing to promptly correct the violations could lead to further action, including seizure of products or an injunction against the company.

Consumers who have refrigerated sour cabbage, kvas or half-sour pickles from RDM Express in their refrigerators are not currently being told to discard them, since no recall has been issued. But federal health officials note that pregnant people, adults 65 and older, and people with weakened immune systems face a much higher risk of severe illness from Listeria than the general population. FDA's Human Foods Program said it will continue to evaluate the company's response once it is received.