High pressure kills pathogens, maintains green onions' taste and color

Mar 20, 2012

Green onions cause about five percent of outbreaks of food poisoning from produce, worldwide. Now a team of researchers from the University of Delaware, Newark, shows that high pressure treatment of green onions can kill various strains of Escherichia coli O157:H7, and Salmonella enterica, two major sources of food poisoning. Unlike heating, the pressure treatment preserves the produce's gustatory attributes. The research is published in the March Applied and Environmental Microbiology.

In the study, the researchers cultivated green onions both in soil and hydroponically, irrigating each with different mixtures of the pathogen strains. The researchers verified that the microbes were taken up by the plants, into their roots, bulbs, stems, and leaves, says corresponding author Haiqiang Chen.

The researchers then grew green onions hydroponically, in water contaminated with the pathogens, for 15 days. At the end of this period, the plants were harvested and placed in a laboratory version of a commercial pressurizer for two minutes, at up to 5,000 times , at 20 or 40 degrees centigrade. In most cases, the pathogens were eradicated by this treatment. "To our knowledge, this is the first research to demonstrate that high pressure processing can kill foodborne pathogens internalized in green onions," says Chen.

In 2003, an outbreak of hepatitis associated with green onions consumed at a restaurant in Monaca, PA, sickened more than 550 people, killing at least three, according to the , and numerous outbreaks of Salmonella and E. coli O157:H7 have been linked to fresh produce.

Explore further: Soil bacteria contribute to the taste and smell of white truffles

More information: H. Neetoo, Y. Lu, C. Wu, and H. Chen. Use of high hydrostatic pressure to inactivate Escherichia coli 0157:H7 and Salmonella enterica internalized within and adhered to preharvest contaminated green onions. Appl. Environ. Microbiol. 78:2063-2065.

Provided by American Society for Microbiology

5 /5 (1 vote)
add to favorites email to friend print save as pdf

Related Stories

E. coli an unlikely contaminant of plant vascular systems

Apr 01, 2011

A technique developed by U.S. Department of Agriculture (USDA) scientists for tracking pathogens has helped confirm that Escherichia coli is not likely to contaminate the internal vascular structure of field-grown leafy ...

Researchers boost beef jerky safety

Mar 24, 2008

The latest spate of meat recalls due to E. coli O157:H7 and Salmonella contamination might have consumers wondering about the safety of their meat products.

Short, sharp shock treatment for E. coli

Jan 11, 2012

A short burst of low voltage alternating current can effectively eradicate E. coli bacteria growing on the surface of even heavily contaminated beef, according to a study published in the International Journal of Food Safe ...

Recommended for you

Plants prepackage beneficial microbes in their seeds

13 hours ago

Plants have a symbiotic relationship with certain bacteria. These 'commensal' bacteria help the pants extract nutrients and defend against invaders – an important step in preventing pathogens from contaminating fruits and ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

Graeme
not rated yet Mar 20, 2012
Equipment to do a 500 MPa compression on a large volume must not be that common. How much would that cost? There would be lots of other interesting things that a pressure chamber like that could do.