Pouched onions prosper under high-pressure water

A system that uses high-pressure water to kill food pathogens helped Winsoms of Walla Walla launch 8-oz and 2 1/2-lb resealable pouches of refrigerated, chopped onions to the Pacific Northwest this month, with nationwide distribution expected by next year.

(Graphics for the 8-oz pack are shown; samples weren’t available at press time.)

Winsoms is the first company in North America to use the high-pressure system for this type of application, according to system maker Avure Technologies. The process is more commonly used for seafood, deli meats, poultry, and prepared foods.

After onions are chopped at the Walla Walla, WA, facility, they're filled and sealed on semi-automatic equipment into preformed, zippered bags supplied by Kapak, or through distributor Centerfield Packaging. Centerfield supplies a 3.5-mil adhesive-lamination. It consists of an oriented polypropylene film from Applied Extrusion Technologies and coextruded polyethylene film from General Films. The OPP layer is reverse-printed in eight colors flexographically and laminated by Sierra Converting, represented by The Packaging Group.

Kapak supplies a 4.5-mil adhesive lamination of 48-ga polyester/4-mil linear low-density polyethylene. The polyester layer is gravure-printed in eight colors.

According to Kevin Greenwald, Winsoms’ founder and general manager, 60 sealed pouches are placed into a 35-L water-bath chamber for about five minutes at 55F, at pressures from 60ꯠ to 100ꯠ psi. Greenwald says the pressure causes total disruption of any living bacteria. E-coli, listeria, you name it, cannot survive the pressure. But the produce stays intact because hydrostatic pressure is equally applied from every direction, causing no damage to the cell wall of the product.

Greenwald explains that the high-pressure processing changes sugar molecules in the onion cells, creating a sweeter product with improved flavor and texture that can be sauteed to a golden, brown color in less than half the time it usually takes. And the bag’s seal integrity is strong, even though there’s nothing out of the ordinary with the film, he says.

He does say that because of the high pressure, the film must allow oxygen ingress. That's necessary because oxygen activates a natural calcium derivative added during filling to help extend shelf life. Most other processed onions have a 10- to 12-day shelf life, says Greenwald. We’ve run shelf-life studies showing that our product's good for 90 days, though we’ll [code] it with a 45-day shelf life.

After the high-pressure process, pouches convey through a Safeline metal detector prior to manual case packing.

The 8-oz packs will sell at traditional retail stores for around $1.50, while the 2 1/2-lb size for warehouse/club stores will retail for $3.

Winsoms has taken three bids for vertical form/fill/seal equipment to automate packaging to accommodate what it hopes will be strong sales demand.

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