Poster Presentation 64th International Conference of the Wildlife Disease Association 2015

Evaluating common storage methods of wildlife corn to reduce aflatoxin production (#161)

Alan M. Fedynich 1 , Brent C. Newman 1 , Scott E. Henke 1 , Greta Schuster 2 , James C. Cathey 3
  1. Caesar Kleberg Wildlife Research Institute, Texas A&M University-Kingsville, Kingsville, Texas, USA
  2. Department of Agriculture, Agribusiness, and Environmental Sciences, Texas A&M University-Kingsville, Kingsville, Texas, USA
  3. Texas A&M AgriLife Extension Service, College Station, Texas, USA

Populations of northern bobwhites (Colinus virginianus) have steadily declined in the United States, prompting wildlife managers to provide supplemental feed.  Grain can contain aflatoxin, which is a harmful fungal metabolite of Aspergillus flavus and Aspergillus parasiticus.  Our objective was to assess common grain storage methods of wildlife corn that can shed light on how to reduce aflatoxin production.  We placed wildlife corn in open air, storage shed, and pavilion environments, and in metal containers, aluminum containers, and plastic containers, which mimicked feeder-type structures.  We determined weekly aflatoxin levels and grain moisture content.   In addition, we monitored weather parameters (daily temperature, relative humidity, and dew point) inside and outside of each storage structure.  Grain moisture and aflatoxin concentrations fluctuated weekly within each type of storage container (F6,28 = 7.23, P < 0.0001) and ranged from 10.4–97.5% and 0–1,200 ppb, respectively.  Each storage type contained corn samples that exceeded recommended aflatoxin levels deemed safe for wildlife within 2 weeks. After 8 weeks of storage, aflatoxin concentrations began to increase significantly in each storage method.  Condensation build-up within metal storage containers increased mold growth on corn, which subsequently resulted in greater aflatoxin concentrations of corn along the sides of such containers compared to corn sampled within the center of the same container.  Black light tests, qualitative tests, and quantitative tests that use small grain samples (<10 g samples) potentially mask the aflatoxin concentration of grain.  Obtaining a low aflatoxin concentration does not necessarily mean low concentrations will occur thereafter, and vice versa.  A high concentration of aflatoxin could be followed by a low concentration of another sample within the same bag of grain because aflatoxin is rarely, if ever, evenly distributed throughout grain.  We recommend storing grain <2 months and to thoroughly clean and dry wildlife feeders often.