Decontamination of Alfalfa Seeds and Sprouts with Ozone

Decontamination of Alfalfa Seeds and Sprouts with Ozone

Fett WF

Plant Science & Technology Research Unit, ERRC, Wyndmoor, PA

CRIS: 1935-41420-005

Agricultural Research Service
National Program 108
Food Safety Progress Report 2001 (web version)
Section 10: Produce and Animal Manure 

Summary Project Aims:

Recent outbreaks of food borne illness due to consumption of raw, contaminated sprouts have shaken consumer confidence in the safety of sprouts. Since 1995 there have been fourteen food borne outbreaks in the US due to contaminated alfalfa, clover and mung bean sprouts. These outbreaks have resulted in over 1300 culture confirmed cases and two deaths. The majority of the outbreaks were caused by various Salmonella serovars, but two were due to contamination with Escherichia coli O157:H7. In addition, sprouts from one grower were recalled due to contamination by Listeria monocytogenes, although no illnesses were attributed to consumption of these sprouts. Both Salmonella and E.coli O157:H7 can cause serious illness and death especially in the very young, old and immunocompromized. The outbreaks have resulted in 1)a reduced market for sprouts, 2)the closure of several sprout growing facilities due to outbreak related litigation and 3)the need for expensive testing of spent irrigation water for pathogens. The primary source of the contamination has been identified as the sprouting seed. New, more effective methods for decontaminating seeds and sprouts are urgently needed to ensure their safety. A collaborative research program on the use of ozone for this purpose began on July 1, 2000. This effort involves Pennsylvania State University (Dr. Ali Demirci), the University of Georgia (Dr. Larry Beuchat) and ARS with funding provided by National Alliance for Food Safety.

Summary Accomplishments During Entire Project:

This is a new project directly related to new (initiated in February 2000) CRIS project no. 1935-41420-005. Under project -005, a seed soak with 20,000 ppm of free chlorine for 10 minutes was found effectively sanitize alfalfa seed naturally contaminated with a bacterial humanpathogen. This seed treatment method is currently recommended to sprout growers by the US FDA. However, equally or more effective alternatives to the use of extremely high levels of chlorine need to be identified as the use of such high levels of chlorine is not desirable due to worker safety and environmental concerns.

Projected Research Accomplishments During the Next 3 Years:

This project is funded for two years. Expected accomplishments for 2001 are: complete studies on elimination of E. coli O157:H7 and L. monocytogenes from seeds by use of ozone; and complete preliminary studies on the effect of ozone on bacteria contained in biofilms on sprouts. In 2002: complete studies on elimination of E. coli O157:H7 and L. monocytogenes from sprouts by use of ozone; complete studies on the effect of ozone on bacterial biofilms on sprouts; and transfer novel decontamination methods to the sprout industry.

2018-11-06T01:36:43+00:00
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