Cape Town – None of the ST6 listeria strain believed to be behind the outbreak that has left 183 people dead since January 2017, was found at the Rainbow polony factory in Wolwehoek, RCL Foods said on Friday amid a precautionary recall of its polony."RCL Foods is pleased to state that tests conducted by an independent laboratory in France, which is considered to be a leading expert in this field, have confirmed that our Wolwehoek plant is clear of the ST6 listeria strain," the company said in a statement. "The listeriosis outbreak is a tragic event and of great concern to RCL Foods. The company expresses its heartfelt sympathy to everybody affected," it said. TIMELINE: This is not the first major listeriosis outbreakHe explained that on Friday January 12, nine children under the age of five presented with febrile gastroenteritis at the Chris Hani Baragwanath Hospital.The paediatrician suspected a food-borne disease, including listeriosis, as a possible cause. Health officials visited the children's crèche and obtained samples from two unrelated polony brands – Enterprise and RCL – and had them tested.Genome sequencing and analysisListeria monocytogenes (a bacteria commonly found in soil and controlled by good hygiene) was isolated from a stool collected from one of the ill children, and from both of the polony specimens collected from the crèche. The samples were sent to the National Institute for Communicable Diseases' Centre for Enteric Diseases and underwent genome sequencing and genomic analysis. Nine sequence types of Listeria monocytogenes were isolated and 91% were sequence type 6 – known as "ST6" – the strain of listeria that the department believes has been driving the outbreak.The outbreak strain of listeria, ST6, was confirmed in at least 16 environmental samples collected by health officials from the Enterprise facility in the Limpopo capital.ALSO READ: 3 500 tons of polony and cold meat returned so farPreliminary results showed that several ready-to-eat processed meat products from the Enterprise facility located in Germiston also contained Listeria monocytogenes, but the sequence type was not known yet. During investigation of the RCL Wolwehoek production facility, Motsoaledi said polony products had tested positive for Listeria monocytogenes, but not the ST6 sequence. However, he said this constituted a health risk.Products taken off shelvesThe National Consumer Commission issued the manufacturers concerned with safety recall notices. RCL pointed out in an earlier bulletin that by March 8 all of its in-store products had been taken off the shelves and bagged, and Tiger Brands told News24 earlier this week that by Monday it had removed 3 500 tons of polony, viennas, cold meats and other chilled meat products from the shelves while it too conducts its own tests.RCL said the listeriosis outbreak has shown that more needs to be done to help consumers understand listeria, and how they can protect themselves and their families. The company said it would continue to review and further entrench its safety policies and procedures.Department of Health spokesperson Popo Maja said he would issue an update on the matter later on Friday.