Tiger Brands is closing a third meat processing factory, this time in Pretoria, after "very low levels of Listeria" were found in products, the company said on Monday morning.
It will also "suspend operations" at an abattoir in Clayville by the end of March. That abattoir supplied all three of its now-shuttered factories.
"Although the level detected was well within the range of government standards for the presence of Listeria, Tiger Brands has taken the precautionary measure of closing the factory," a statement by Tiger Brands statement read.
The company closed two Enterprise factories in Polokwane and Germiston after health minister Aaron Motsoaledi identified cold meats from the factories as the "definite source" of the country's listeriosis outbreak at the beginning of March.
More than 180 people have died from Listeria in South Africa since January 2017.
The company said tests in March confirmed the presence of Listeria at the Polokwane factory, but said no direct link has yet been established between the Listeria at the factories and the death of South Africans.
Tiger Brands' Polokwane, Germiston and Pretoria factories are undergoing an extensive deep cleaning of all the equipment and machinery, the company's CEO Lawrence Mac Dougall said.
"During this period of investigation and discovery we have decided to be extra cautious and to take immediate precautionary action when traces of Listeria are detected where they are not expected," Dougall said.
It was still waiting for the results of whole-genome sequencing to determine if the Listeria detected at the Pretoria factory was of the ST6 strain, which has been linked to the majority of deaths in the current outbreak.