Featured Research

from universities, journals, and other organizations

Protozoa May Enable Food-Borne Pathogens On Leafy Vegetables

Date:
April 27, 2008
Source:
American Society for Microbiology
Summary:
Protozoa found on lettuce and spinach may sequester harmful food-borne pathogens ultimately contributing to their survival on produce surfaces. Several outbreaks of food-borne illnesses attributed to Escherichia coli O157:H7 and Salmonella enterica have received national attention in recent years. The Centers for Disease Control and Prevention reported that fresh produce was the most significant source of food-borne illness in 2005.

Protozoa found on lettuce and spinach may sequester harmful food-borne pathogens ultimately contributing to their survival on produce surfaces say researchers from Tennessee Technological University, Cookeville and the Produce Safety and Microbiology Research Unit, Albany, California.

Several outbreaks of food-borne illnesses attributed to Escherichia coli O157:H7 and Salmonella enterica have received national attention in recent years. The Centers for Disease Control and Prevention reported that fresh produce was the most significant source of food-borne illness in 2005.

Protozoa are single-celled organisms whose main function is bacterial consumption. They are commonly found in the natural microflora of plants and several species of amoebae have been associated with fresh salad vegetables. The recent occurrence of multiple outbreaks has encouraged researchers to further examine the interaction between food-borne pathogens and protozoa.

In the study protozoa (Glaucoma sp., Colpoda steinii, and Acanthamoeba palestinensis) as well as the soil-borne strain, Tetrahymena pyriformis, were cultured from store-bought spinach and lettuce and washed and allowed to graze on green fluorescent protein- or red fluorescent protein-labeled enteric pathogens including E. coli O157:H7, S. enterica, and Listeria monocytogenes.

They were then monitored for their ability to sequester the bacteria and for vesicle production (food vacuoles released by protozoa offering a means of protection to some bacteria). Results showed Glaucoma produced vesicles with all bacterial strains and Tetrahymena also displayed vesicle production, but only of E. coli O157:H7 and S. enterica, not L. monocytogenes. Further studies of E. coli O157:H7 following vesicle production revealed that 4 hours after the addition of spinach extract, the bacteria had multiplied and escaped the vesicles. C. steinii did not produce any vesicles from any of the pathogens.

"The presence of protozoa on leafy vegetables and their sequestration of enteric bacteria in vesicles indicate that they may play an important role in the ecology of human pathogens on produce," say the researchers.

Journal reference: P. Gourabathini, M.T. Brandl, K.S. Redding, J.H. Gunderson, S.G. Berk. 2008. Interactions between food-borne pathogens and protozoa isolated from lettuce and spinach. Applied and Environmental Microbiology, 74. 8: 2518-2525.


Story Source:

The above story is based on materials provided by American Society for Microbiology. Note: Materials may be edited for content and length.


Cite This Page:

American Society for Microbiology. "Protozoa May Enable Food-Borne Pathogens On Leafy Vegetables." ScienceDaily. ScienceDaily, 27 April 2008. <www.sciencedaily.com/releases/2008/04/080425095200.htm>.
American Society for Microbiology. (2008, April 27). Protozoa May Enable Food-Borne Pathogens On Leafy Vegetables. ScienceDaily. Retrieved August 29, 2014 from www.sciencedaily.com/releases/2008/04/080425095200.htm
American Society for Microbiology. "Protozoa May Enable Food-Borne Pathogens On Leafy Vegetables." ScienceDaily. www.sciencedaily.com/releases/2008/04/080425095200.htm (accessed August 29, 2014).

Share This




More Plants & Animals News

Friday, August 29, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Killer Amoeba Found in Louisiana Water System

Killer Amoeba Found in Louisiana Water System

AP (Aug. 28, 2014) State health officials say testing has confirmed the presence of a killer amoeba in a water system serving three St. John the Baptist Parish towns. (Aug. 28) Video provided by AP
Powered by NewsLook.com
Raw: Australian Sheep Gets Long Overdue Haircut

Raw: Australian Sheep Gets Long Overdue Haircut

AP (Aug. 28, 2014) Hoping to break the record for world's wooliest, Shaun the sheep came up 10 pounds shy with his fleece weighing over 50 pounds after being shorn for the first time in years. (Aug. 28) Video provided by AP
Powered by NewsLook.com
Minds Blown: Scientists Develop Fish That Walk On Land

Minds Blown: Scientists Develop Fish That Walk On Land

Newsy (Aug. 28, 2014) Canadian scientists looking into the very first land animals took a fish out of water and forced it to walk. Video provided by Newsy
Powered by NewsLook.com
Huge Ancient Wine Cellar Found In Israel

Huge Ancient Wine Cellar Found In Israel

Newsy (Aug. 28, 2014) An international team uncovered a large ancient wine celler that likely belonged to a Cannonite ruler. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins