Source: NORTH DAKOTA STATE UNIV submitted to
PHYSICAL TREATMENTS TO PREVENT FUSARIUM GROWTH AND MYCOTOXIN PRODUCTION DURING THE MALTING OF BARLEY
 
PROJECT DIRECTOR: Wolf-Hall, C. E. Schwarz, P. Panigrahi, S.
 
PERFORMING ORGANIZATION
VETERINARY & MICROBIOLOGICAL SCIENCES
NORTH DAKOTA STATE UNIV
FARGO,ND 58105
 
NON TECHNICAL SUMMARY: Fusarium infections in grains have been a persistent problem for the upper Midwest. These result in mycotoxin contamination of grain. Mycotoxins cause chronic and acute toxicoses in humans and animals. Infected grain also causes severe economical consequences due to lost income from discounted sales. A problem with malting barley is during malting, mold can begin to grow and produce more mycotoxins which survive kilning and remain biologically active. This post-harvest growth of the Fusarium also affects the quality of the malt produced. The industry has set tolerance levels for any deoxynivalenol (DON or vomitoxin) present in barley at or below 0.5 g/g. The Food and Drug Administrations guideline level for DON in food ingredients destined for human consumption is 1 g/g. The theory behind these severe industry restrictions is that if any DON is present, then there is Fusarium present which may grow during malting. In recent years it has been difficult for producers to get premium prices for malting barley and much of the barley from the upper Midwest has ended up as animal feed, even though it may contain levels of mycotoxins well within FDA guidelines for human consumption. We will investigate the effectiveness of two irradiation methods to pasteurize barley. These physical treatments may prevent growth of mold during malting while not seriously affecting germinative capacity of the barley or other malting attributes. This pasteurizing process will allow the use of mildly Fusarium infected barley for malting without the safety concern of further mycotoxin production.
 
OBJECTIVES: 1. To determine the effect of two different types of irradiation on Fusarium survival in and malting characteristics of three cultivars of Fusarium infected barley. 2. To determine the effects of two different types of irradiation on the mycotoxin producing ability of surviving Fusarium graminearum isolates.
 
APPROACH: Objective 1. This will be a randomized complete block design. Three, naturally infected barley cultivars will be compared for the effect of irradiation on barley germination, Fusarium survival, and mycotoxin (DON, 15-acetylDON, 3-acetylDON, nivalenol and zearalenone) content. Other variables will be the dosage of electron-beam irradiation and UV-C irradiation distance and time of exposure. Controls will be non-irradiated barley samples. The treatments will be repeated three times and the results compared. The barley samples showing the most significant decreases in Fusarium levels, as shown by percent kernel infection, while maintaining germinative ability will be malted and the malt tested for malt quality parameters, ergosterol content as an indicator of fungal biomass and mycotoxin content (DON, 15-acetylDON, 3-acetylDON, nivalenol and zearalenone). Again, controls will be non-irradiated samples. Objective 2. This will be a completely random design. Isolates of Fusarium graminearum from the three barley cultivars treated at the different irradiation doses (including non-irradiated control samples) will be taken and grown under defined laboratory conditions. The mycotoxin producing ability will be determined by testing the cultures for DON, 15-acetylDON, 3-acetylDON, nivalenol and zearalenone production in culture.
 
CRIS NUMBER: 0189772 SUBFILE: CRIS
PROJECT NUMBER: ND05297 SPONSOR AGENCY: CSREES
PROJECT TYPE: NRI COMPETITIVE GRANT PROJECT STATUS: TERMINATED MULTI-STATE PROJECT NUMBER: (N/A)
START DATE: Dec 15, 2001 TERMINATION DATE: Dec 31, 2004

GRANT PROGRAM: ENSURING FOOD SAFETY
GRANT PROGRAM AREA: Nitrogen Fixation

CLASSIFICATION
Knowledge Area (KA)Subject (S)Science (F)Objective (G)Percent
712155011024.1100%

CLASSIFICATION HEADINGS
KA712 - Protect Food from Contamination by Pathogenic Microorganisms, Parasites, and Naturally Occurring Toxins
S1550 - Barley
F1102 - Mycology
G4.1 - Reduce Incidence of Foodborne Illnesses and Contaminants


RESEARCH EFFORT CATEGORIES
BASIC (N/A)%
APPLIED 100%
DEVELOPMENTAL (N/A)%

KEYWORDS: fusarium; mycotoxins; barley; irradiation; ultraviolet radiation; germination; malting; food contamination; food quality; physical treatment; survival; performance evaluation; cultivars; fusarium graminearum; nivalenol; zearalenone; electron beam; comparative analysis; controls; ergosterol; biomass; dosage; quality maintenance

PROGRESS: Dec 15, 2001 TO Dec 31, 2004
We expanded our irradiation study to include different levels of Fusarium infection and malt quality analyses. Irradiation was done at a Surebeam Corporation plant in Chicago, with dosages of 0, 2, 4, 6, 8 and 10 kGy. Treatments were repeated three times on different days. Treated samples were malted in a pilot-scale malting unit at North Dakota State University. The barley samples were analyzed for Fusarium infection (FI), germinative energy (GE), aerobic plate counts (APC), and mold and yeast counts (MYC) and deoxynivalenol (DON). Malted barley samples were analyzed for FI, APC, MYC, and DON. FI decreased with increase in radiation dosage in both the barley and malted samples. In barley samples exposed to 10 kGy, FI was reduced by 50-98%. APC significantly decreased (1-5 logs) in barley with increase in irradiation dosage. A 5-log reduction in APC was observed at 10 kGy for all barley samples. MYC significantly decreased in barley with increase in irradiation dosage. A 1-2.5 log reduction in MYC was observed for all barley samples exposed to 10 kGy. DON was reduced to 0.5 ppm or less in malts from barley treated with 2 kGy and higher. Pre-harvest formed DON was likely washed out during steeping. APC and MYC in malts from 8-10 kGy treated barleys were slightly higher than in other malts indicating that radiation resistant microflora were able to thrive during malting due to decreased competition. GE in barley samples was significantly decreased (3-15%) at dosages of 8-10 kGy. The results suggest that dosages between 6-8 kGy may be effective in reducing DON in malt while maintaining the GE in barley. Dosages over 8 kGy reduce GE and appear to lead to higher microbial loads in malt. Minimal effects to malt quality were seen at 6-8 kGy.

IMPACT: 2001-12-15 TO 2004-12-31 Fusarium head blight (FHB) has become a severe and devastating problem in some areas of the United States which produce small grains. This plant disease and the mycotoxin, deoxynivalenol (DON, vomitoxin), associated with it may present a serious public health concern and lead to price discounts for infected grain resulting in severe economic consequences to small grain producing regions. The objectives of this project are intended to lead to methods to control DON concentrations in post-harvest malting barley so that mildly FHB infected barley can be utilized for malting without safety or quality concerns.

PUBLICATION INFORMATION: 2001-12-15 TO 2004-12-31
No publications reported this period

PROJECT CONTACT INFORMATION
NAME: Wolf-Hall, C. E.
PHONE: 701-231-6387
FAX: 701-231-6536