Eight people infected with the outbreak strains have been reported from three states since September 13, 2013.
A Worker Adjustment and Retraining Notification (WARN) act notice from the Washington State Employment Security department said layoffs started on 3 May.
Current evidence indicates that frozen vegetables produced by CRF Frozen Foods are the likely source of illness, said the Centers for Disease Control and Prevention (CDC).
FDA inspection findings
The US Food and Drug Administration (FDA) inspected the plant from March 14-17 this year and observed that the ‘materials and workmanship of equipment and utensils does not allow proper cleaning and maintenance’.
They found a chipped and cracked plastic shovel used for food contact, issues with the onion production line and blue tape used as a temporary fix to a cracked metal plate above a packing line which, during the inspection, was running product designated for export.
CRF suspended operations at its Pasco, Washington facility on the morning of April 25, following the initial recall.
On May 2, the firm expanded this recall to include all organic and traditional frozen vegetable and fruit products processed in the facility since May 1, 2014.
This includes 358 consumer products sold under 42 separate brands that have the best by dates or sell by dates between April 26, 2016 and April 26, 2018.
Investigations are ongoing to determine which food source used to manufacture products could explain some illnesses.
Listeria specimens were collected from September 13, 2013 to March 28, 2016. Two illnesses were reported this year.
All eight ill people were hospitalized, including one each from Maryland and Washington who died, although listeriosis was not considered to be a cause of death.
As part of a routine product-sampling program, the Ohio Department of Agriculture isolated Listeria from True Goodness by Meijer brand frozen organic white sweet cut corn and True Goodness by Meijer brand frozen organic petite green pea, both made by CRF Frozen Foods.
The Canadian Food Inspection Agency (CFIA) has recalled a number of products but no illnesses have been reported in the country.
Sprout outbreak over
Meanwhile, an outbreak of Salmonella linked to alfalfa sprouts has ended, according to the CDC.
Twenty-six people infected with the outbreak strains of Salmonella Muenchen (25 people) or Salmonella Kentucky (1 person) were reported from 12 states.
Sweetwater Farms withdrew alfalfa sprouts in late February but illnesses continued to be reported.
Investigations found alfalfa sprouts made by multiple producers from one lot of contaminated seeds were the likely source.
According to FDA, no sprouts from the contaminated seed lot should be on the market.