Microbiological Safety of Organic Fruits and Vegetables

In past years an increased number of infectious outbreaks have been associated with the consumption of fresh fruits and vegetables. Since these products are consumed raw, they are considered high-risk because they are susceptible to bacterial contamination. The spread of food-borne pathogens can occur either by direct contact of produce by soil fertilized with animal waste, through contaminated irrigation water, and during post-harvest handling and washing.

The study entitled “Microbiological Safety of Organic Fruits and Vegetables” is funded through the Sustainable Agriculture Research and Education Program, and is being conducted by the University of Minnesota, Department of Food Science and Nutrition and the Southwest Research and Outreach Center at Lamberton, MN. This project is coordinated by Dr. Francisco Diez-Gonzalez (Assistant Professor of Food Safety Microbiology), with participants Pauline Nickel (Head of SWROC and Co-Project Coordinator), Avik Mukherjee (Ph.D. candidate in the Department of Food Science and Nutrition), and Dorinda Speh (Assistant Scientist at SWROC).

The project is the first systematic approach for the determination of microbiological quality of organic fruits and vegetables at the pre-market stage. The presence of indicator bacteria (coliforms, Escherichia coli) and pathogens (E. coli O157:H7, Salmonella) will be determined in fruits and vegetables produced by approximately 60 organic and conventional growers in Minnesota and Wisconsin. Trace-back investigations will be conducted by comparing bacterial strains isolated from environmental samples (soil, water, and compost) and from produce. Study results will assist farmers in assessing their practices and incorporating microbiologically safe management improvements. Communication of results and findings will be available on the internet, in newsletters and scientific publications.

Researchers:

Francisco Diez-Gonzalez, University of Minnesota Department of Food Science and Nutrition

Technical Support:

Dorinda Speh, SWROC Assistant Scientist

Published Papers:

Preharvest Evaluation of Coliforms, Escherichia colia, Salmonella, and Escherichia coli L157:H7 in Organic and Conventional Produce Grown by Minnesota Farmers.” Journal of Food Protection, Vol. 67, No. 5, 2004, 19(1):894-900, 2004.

Funding:

Rapid Agricultural Response Fund (U of M)
North Central Regional SARE Program