Defendant Lyu Yueting was charged with deploying dangerous substances in the poisoning case, which resulted in four Chinese and nine Japanese citizens becoming ill, one seriously, China's state-run news agency Xinhua reported.
Lyu confessed to the crime in court, telling those present he was sorry and he didn't expect such serious consequences.
Lyu worked at the Tianyang Food Plant in Shijiazhuang, Hebei's provincial capital. Prosecutors said he was unhappy with his pay and tried to create an incident to draw attention of managers in hopes of raising his salary.
Prosecutors said Lyu injected insecticide into six to nine boxes of frozen dumplings from October to December of 2007.
The court said a verdict would be announced later. Xinhua said the trial Tuesday lasted three hours.
Xinhua said Chinese law permits the death penalty when a defendant is found guilty of deploying dangerous substances if the action causes serious injury, death or the loss of property.