The company linked to a deadly Listeria outbreak has revealed it has found the cause of contamination at its Hungarian plant.

Greenyard said it found a persistent presence of Listeria monocytogenes in one of the freezing tunnels and as a result, will close down this tunnel at the Baja-based plant.

The Hungarian frozen vegetable factory is believed to be the source of a Listeria outbreak that sickened 54 people in six countries, killing 10 of them. Eighteen outbreak cases were reported in 2018 with the latest having disease onset in May 2018.

In June, the Hungarian Food Chain Safety Office (NEBIH) banned marketing of certain frozen products from the plant between Aug. 13, 2016, and June 20, 2018, and ordered a product withdrawal and recall.

Illnesses as part of the outbreak were reported in Austria, Denmark, Finland, Sweden, the United Kingdom, and Australia. Implicated frozen products were distributed to 116 countries and have a long shelf-life (some until mid-2020).

A spokesman for Greenyard told Food Safety News that product should be on the shelves in the next few days.

“We are running our release procedures and will be able to restart our production and distribution on the back of that. We recalled two years’ worth of production and we are seeing that product flowing back or being destroyed. We can therefore only conclude that the product that was potentially contaminated is no longer in the chain,” he said.

“Consumers can safely consume the products that are on the shelves of the retailers. In line with the authorities, we do continue to underline that it is important to always follow the cooking instructions on the packaging.”

With the restart of the plant, Greenyard said it was confident the financial impact of the recall will remain within €30 million ($35 million) net after insurance.

“Greenyard has conducted, in full collaboration with the authorities and independent experts, a large in-depth review of the facility to identify the root cause of the potential contamination. This review has been successful, resulting in the identification of the Listeria root cause, given predominantly a persistent presence of Listeria in one of the two freezing tunnels,” the firm said in a statement.

The company announced last month that it would restart production after all tests at the production site were negative for the presence of Listeria monocytogenes following shutdown and cleaning.

Greenyard decided to close down the implicated tunnel which makes up around 3 percent of the volume produced by the firm’s frozen division and has reviewed clearance of the facility with authorities.

“It is a smaller tunnel and also only represents a minor part of the volumes we produce in our frozen activities. We can move the volume to other tunnels allowing us somewhat more time to contemplate how we see the future for this tunnel,” said the spokesman.

The company will supply customers with products from its Hungarian facility and has secured alternatives to compensate for temporary unavailability of certain products. These alternatives include the firm’s other plants in Europe or through subcontracting of volumes from other players in the market.

The firm said it has adopted a series of stringent release procedures and will maintain these as long as it deems necessary. It will also produce at stricter levels below the legal thresholds and implement additional safety and cleaning measures.

The Greenyard spokesman said it will not release products from the Hungarian plant, unless tests demonstrate absence of Listeria monocytogenes.

“In all of our other plants, and group-wide, we are also, at our own initiative, using more stringent levels than the legal norms (of 100 colony forming units per gram). We are currently producing at < 10 cfu/g. Together with external experts, we have further improved and fine-tuned our cleaning, disinfection, and swab testing procedures based on our experience of the current case,” he said.

The European Centre for Disease Prevention and Control (ECDC) and European Food Safety Authority (EFSA) said the outbreak is thought to have started in 2015.

The same strains of Listeria monocytogenes were detected in frozen vegetables produced by the company in 2016, 2017 and 2018.

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