Assessment of mycotoxins in Vitis vinifera wines of the Southeastern United States

Authors: BOLTON, STEPHANIE - University Of Georgia; Mitchell, Trevor; BRANNEN, PHILLIP - University Of Georgia; Glenn, Anthony - Tony

Submitted to: American Journal of Enology and Viticulture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/9/2017
Publication Date: 3/9/2017
Citation: Bolton, S.L., Mitchell, T.R., Brannen, P.M., Glenn, A.E. 2017. Assessment of mycotoxins in Vitis vinifera wines of the Southeastern United States. American Journal of Enology and Viticulture. doi:org/10.5344/ajev.2017.16089.

Interpretive Summary: Mycotoxins pose a serious worldwide threat to the safety of numerous agricultural commodities, including red wine that is particularly prone to contamination from the mycotoxin ochratoxin A produced by certain species of Aspergillus. Some of these same species can also produce the mycotoxin fumonisin B2. Although wine surveys in most regions of the world have determined that ochratoxin A levels are below the recommended guideline limits, it remains important to monitor toxin levels in wine to ensure safety, especially in poor vintages and in regions where wine production is new, such as the southeastern United States. The hot, humid environment of the southeastern U.S. is very challenging to winegrapes due to high disease pressure from fungi, yet there are currently over 550 wineries in this region. To determine the mycotoxin potential in southeastern vineyards, grape clusters were collected in 2013 across three states and eight vineyards (representing 10 grape varieties) and analyzed for ochratoxin A and fumonisins. Only one grape sample was positive for mycotoxins (fumonisin B1) out of 30 tested, and it was well below guideline limits. Additionally, nearly 200 bottles of 100% southeastern grown red grape wines were tested for mycotoxins. These wines represented 18 grape varieties grown across six states during vintages from 2001 to 2013. Only four out of 157 (2.5%) wines tested positive for ochratoxin A, with even the highest quantity being at a safe level. Most of the wines that were tested for fumonisins (25 out of 27 wines, or 92.6%) contained total fumonisins (B1, B2, and B3) at extremely low concentrations, far below a health risk level. Based on these results, the southeastern U.S. wine industry has a low occurrence of the mycotoxin ochratoxin A and insignificant amounts of fumonisins in red wines, despite the high disease pressure and presence of mycotoxin producing fungi.

Technical Abstract: Mycotoxins pose a serious worldwide threat to the safety of numerous food commodities. Red wine is prone to contamination from ochratoxin A, produced by black-spored Aspergillus spp., and it was recently discovered that some of these species can also produce the mycotoxin fumonisin B2. Although wine surveys in most world regions have determined that mean ochratoxin A levels are below the European Union’s recommended guideline maximum (2 µg/L), it remains imperative to monitor toxin levels in poor vintages and in emerging regions to ensure safety. The hot, humid environment of the southeastern U.S. proves challenging to winegrapes due to opportunistic fungal growth and high disease pressure, yet there exists 550+ wineries in this expanding region. To determine the mycotoxin potential in southeastern vineyards, 30 cluster samples (representing 10 grape varieties, eight vineyards, and three states) were collected during the 2013 harvest and analyzed for ochratoxin A and fumonisins. Additionally, nearly 200 bottles of 100% southeastern U.S. red, vinifera wines were tested for mycotoxins via LC-MS/MS. These wines represent 18 grape varieties grown across six states during vintages between 2001 to 2013. Only 4/157 (2.5%) wine samples tested positive for ochratoxin A, with the highest quantity being at a safe level of 0.48 µg/L. Most wines (25/27, 92.6%) contained total fumonisins (B1, B2, and B3) at extremely low concentrations (<15 µg/L), far below a health risk level. Only one grape sample was positive for mycotoxins (20.6 µg/L fumonisin B1) out of 30 tested. Based on these results, the southeastern U.S. Vitis vinifera wine industry has a low occurrence of the mycotoxin ochratoxin A and insignificant amounts of fumonisins in red wines.