Barry Callebaut has halted production at its Wieze plant in Belgium, which it says is the world's biggest chocolate factory, after discovering salmonella in a production lot on Monday, the Swiss chocolate maker said on Thursday.
"Barry Callebaut informed the Belgian food authorities (FAVV) about the incident and has taken the precautionary measure to stop all chocolate production lines and to block all products manufactured since the time of testing.
"We are currently reaching out to all customers who may have received impacted products. The chocolate production in Wieze will remain suspended until further notice," it said on its website.
The company's quality experts identified lecithin as the source of the contamination, it said.
"As lecithin is used in all chocolate production, we have taken the precautionary measure to stop all production lines and to block all products manufactured since the time of testing, while we continue the root cause analysis and risk assessment," it said.
It also asked customers to block any shipped products.
"Barry Callebaut will now take the time to continue with the very diligent root cause analysis - keeping the FAVV informed in the process. When that is completed the lines will be cleaned and disinfected before resuming the production process," it said.
Its shares fell 2.6% by 1150 GMT.