China's top market regulator has fined seven major e-commerce and food delivery platforms a combined 3.6 billion yuan ($500 million) for violations linked to so-called "ghost kitchen" operations, in what is one of the country's largest online food safety penalties to be levied to date.

The State Administration for Market Regulation said on Friday it had penalized units of Pinduoduo, Meituan, JD, Alibaba-backed delivery service Ele.me, short-video platform Douyin, as well as Taobao and Tmall, for failing to properly vet food vendors operating on their platforms.

In addition to the 3.6 billion yuan, an additional 19.69 million yuan in personal fines was levied on legal representatives and food safety executives across the seven firms for failing to fully discharge their management responsibilities.

Regulators found that the platforms did not adequately verify the business licenses of online food merchants and failed to meet their legal obligations for qualification checks, according to the statement.

Authorities also said the companies entered into cooperation agreements with order-routing intermediaries and did not take necessary measures despite knowing — or having reason to know — that such practices could harm consumer rights.

The penalties were imposed under China's food safety and e-commerce laws. In addition to ordering the companies to rectify their conduct, regulators suspended the onboarding of new cake and dessert vendors on the platforms for periods ranging from three to nine months.

The probe found that senior management at the platforms bore direct responsibility for lapses in food safety oversight, violating multiple provisions under China's food safety and e-commerce regulatory frameworks.

Following the launch of the investigation, regulators ordered immediate corrective action. All seven platforms have since removed unverified "ghost" vendors and halted cooperation with third-party order-routing platforms involved in the violations.