“This year, many people prefer our 10-minute quantitative ROSA test because it is a single dilution test for 0-150 ppb samples.” Jabour explains. “If the sample is greater than 30 ppb, a dilution is sometimes needed with our three-minute test.”
Jim Cary, national sales manager for VICAM of Milford, MA, agrees there is still a place in the market for tests with incubation periods longer than three minutes, and notes years ago all mycotoxin tests took up to an hour to produce results.
“People would like to be able to insert something into a truck and instantly see if there are toxins present, but that’s not realistic,” Cary says. “We can, however, within about five minutes, give you accurate results anywhere from less than 2 ppb up to 100 ppb with our Afla-V™ test strips and VICAM’s Vertu™ Lateral Flow Reader.”
The old adage “patience is a virtue” rings true with testing now more than ever. Taking the time to properly sample, prepare the sample for analysis and utilize the best testing method for the application will pay off. Managing grain based on toxin levels can help maintain quality during long-term storage and aid in marketing and merchandising.
Storage and marketing considerations
In the high stakes game of quality standards, the marketability of your grain relies on knowing precisely the risks present. Neogen’s Frasco sums it up: “Testing is so important because it allows you to make better merchandising decisions. Identifying specific toxin levels so you can segregate grain at different levels of impact will help you sell one grade to ethanol facilities, another grade to cattle feeders and a different level to pet food manufacturers.”
But it’s not enough to test upon receiving, put it into storage and hope that nothing changes. In-bin mold growth can be as severe a problem as heightened incoming aflatoxin levels.
Dr. John L. Richard, former president and CEO and current consultant for Romer Labs of Union, MO, has worked for the USDA-ARS National Animal Disease Center, was a member of the faculty of toxicology at Iowa State University and was a research leader at the National Center for Agricultural Utilization Research. Richard recalls that aflatoxin was solely considered a storage problem until 1975 when it was found in Iowa corn as it was brought in from the field. Although it’s now known that most toxins take hold before the grain hits the storage bin, Richard warns that aflatoxin levels can rise afterward if poorly managed.
“Corn should be dried down to 14% moisture level before going into the bin,” he says. “We also know broken kernels are likely to contain more toxins after harvest, so it’s a good idea to screen your corn and get rid of the fines before it goes into storage.”
It’s also wise to regularly test and monitor for changes in toxin levels as grain is transferred out of the bin and shipped out, carried over or blended. Just because it went into the bin at 20 ppb of aflatoxin, doesn’t mean it’s going to come out in that condition next spring or summer.
“Aflatoxin is produced by a living organism and it will grow in storage,” VICAM’s Cary states. “Sometimes it even grows better in storage than in the field, so in addition to safe storage practices, I would recommend testing when it goes in, repeating every three months after that and then when you ship it out to the end user.”
Keeping bins in top shape is Frasco’s last bit of advice. “Keep an eye out for bins with airflow issues or malfunctioning temperature cables. Anything wrong in the bin might impact toxin levels.”