UH Moment: "Lettuce Wash"

A simple and inexpensive device to wash leafy produce, created by students at the UH Conrad N. Hilton College of Hotel and Restaurant Management (HRM), may provide a convenient way for small farmers to clean produce before market.

"Leafy greens have the highest incidence of food-borne illness outbreaks from a variety of pathogens nationwide," said graduate student Cecilia Zerio Egli. "There is not a lot of research available for smaller farms to access methods for efficiently and economically washing produce before it goes to markets."

Zerio Egli is studying in the HRM Food Safety Laboratory, directed by Professor Jay Neal.  The laboratory performs microbiological and sensory research, while collaborating and publishing with other universities and government agencies. In addition, the lab has a full production kitchen, aswell as a sensory evaluation laboratory. In August 2012, the lab will achieve a Bio-Safety Level 2 upgrade, which will enable researchers to work with pathogenic or disease-causing microorganisms.

 Supported by a grant from the Texas Department of Agriculture,  Zerio Egli and Neal surveyed more than 80 local and regional farmers about their harvesting and washing practices, asking if they would use a washing device if it were available.  "Small famers" were defined as earning less than $500,000 annually. These farms are exempt from the Food and Drug Administration's Food Safety Modernization Act, which focuses on preventing food contamination rather than responding to outbreaks. 

Unlike large commercial farms that can ship produce to packing facilities that wash the vegetables, smaller farmers must do everything themselves, from harvesting and packaging to transporting to market. Not all produce is washed before heading to market. 

The lettuce washing apparatus in action"Packing sheds have flumes which are water-wash systems with a chlorinated treatment," Neal said. "When you buy packaged lettuce that says 'washed three times' that's how it was done.  Small farmers don't have that."

Zerio Egli's device is made from PVC pipe, a stainless steel strainer and a five-gallon drum.  Leafy vegetables placed inside the stainless steel container are spun as they're showered briefly with water to remove dirt.  With the flick of a lever, the container lowers into the plastic drum where it is spun in a vinegar and water solution, proven to best clean produce of any harmful bacteria.  Finally, the container is lifted to its original position where the produce is rinsed with water again.

"I'll be making an information sheet which will have the plans for how small farmers can easily build the device themselves and where they can purchase the inexpensive materials," she said. "And farmers can manipulate the size to fit their individual needs."  The information sheet also will have resources for farmers about best practices when growing, harvesting and washing produce. 

Zerio Egli and Neal plan to make the plans available in the fall to farmers and farmers' markets.