The latest updates are in blue. 11/3/00;Revised 11/8/00 1 C:\WINDOWS\Desktop\StarLink\ActionC doc

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1 The latest updates are in blue. 11/3/00;Revised 11/8/00 1 C:\WINDOWS\Desktop\StarLink\ActionC doc ACTION CHECKLIST FOR STARLINK CORN PRODUCERS AND ELEVATORS DR. CHARLES R. HURBURGH, JR. Background The Aventis Bt corn event StarLink (Cry9c) is approved by FDA, USDA, and EPA only for animal feed use but not for human consumption, either directly or as processed product. Not all producers of StarLink were aware of these limitations, and there was no economic incentive before October 6, 2000, to isolate StarLink for livestock-only use. At least 50% of Iowa s corn harvest was completed before this date. StarLink in unknown quantities is likely present in commingled grain storage at many elevators. For a discussion of the StarLink issue and its extent, please see "The Starlink Situation" at StarLink was grown in nearly every corn-producing state and was scattered widely within states. Processors and some livestock producers are reportedly testing for StarLink. There is no tolerance level at this point; no StarLink is allowed in food uses. Even areas with lesser production levels are potentially capable of having rejected shipments. There are two distinct classes of corn identified by their ability to be determined StarLink free. Corn delivered to elevators at or right after harvest without testing is potentially mixed with StarLink, at unknown levels. Corn still on the farm can be identified and/or tested before delivery to a market. StarLink on the farm is eligible for a premium from Aventis. Thus, grain handlers, on their current inventories, face the primary risk. Following are possible actions producers and elevators can take to minimize expansion of risk. Producers (with stored grain) If you produced StarLink, determine what storage bins contain the StarLink in any concentration. One 500-bushel load in a 20,000-bushel bin is still 2.5%. The detection limit of the strip test kits is 0.25%. Contact Aventis through your seed supplier. Do not deliver any of this corn to the elevator. If you cannot determine which bins the StarLink is in, assume it is in all bins. Fields adjacent to your StarLink fields could have trace levels from cross-pollination. If you did not produce StarLink, the cross-pollination problem still exists. Contact all producers of corn adjacent to your fields, including across a road. If one or more of these producers grew StarLink or are unwilling to share information, you should test stored corn that came from fields near the StarLink or unknown fields. At this time, it is not clear how producers access testing and if the costs of related operations over and above the test kits will be reimbursed. A possible sampling plan and sample handling process is shown below. To avoid unnecessary testing, it is important to eliminate by documentation as many storage bins as possible. Without

2 11/3/00;Revised 11/8/00 2 C:\WINDOWS\Desktop\StarLink\ActionC doc some form of records as to what grain is in what each bin, you may have to test all of them. A major key to regaining control over the integrity of corn markets is to limit StarLink lots to what is already in the system. Producers now have a legal responsibility to deliver merchantable and useable products regardless of what information seed companies or neighbors may have provided. Cooperation and information sharing are likely to be the best strategies for working through this problem. Grain Elevators Elevators have two distinct inventories to maintain corn received during harvest and of unknown hybrid, and corn received after the need for isolation of StarLink became apparent. The first inventory unknown corn is the inventory at risk. Do not expand this inventory by mixing any future corn, of known or unknown hybrid, with that which cannot be verified. The only reliable way to sample inventory already on hand is from a flowing stream, during a transfer operation. If this is done during loadout (of rail cars, barges, etc.), expect slowdown in loading rate. The strip test kits take minutes considering both the test and sample preparation time. The tests are designed to detect presence of StarLink to about 0.25% IN THE SAMPLE TESTED. If, for example, one car gets a positive, assume the rest of the cars being loaded from the same bin or pile could easily test positive on a future sample at the receiving point. See below for more on sampling. If a pile or bin must be probed, try to get about 10 lbs of sample for every 50,000 bushels (the same as would be done for a barge or an ocean vessel sublot). Test each 10 lb subsample; if there is one positive test, you should assume the entire lot contains StarLink. The purpose of the testing is to detect presence of StarLink, not to measure the amount present. This is why any detection in a lot must be considered the whole lot, but it also means that the sampling process must only find some, but not necessarily a representative concentration. The most difficult testing will occur in areas where the StarLink levels are very low, below %, because the chances of a false positive increase sharply with reduction in concentration. For the grain yet to arrive, do not try to test as grain is received. The cost of the testing becomes very high per bushel, time delays are objectionable, and the chances of poor tests are increased. Pre-qualify deliveries as being with or without StarLink. There are several ways to pre-qualify grain as clear of StarLink. Communication with the producer is the most important thing that can be done; get the same information he has. Assist the producer in making the decisions as to which bins to test. Know which bins a producer is delivering from and whether those bins have been pre-qualified, either by test or by documentation. Producers unwilling to share

3 11/3/00;Revised 11/8/00 3 C:\WINDOWS\Desktop\StarLink\ActionC doc information should be reminded of their legal responsibility regarding merchantability. The Iowa certification form is one way to communicate this responsibility. Save a composite sample from each load delivered by the producer and from each bin of each producer if possible. One way to do this would be to place a portion of the office sample from each load in a plastic sample bag. Since moisture is not a concern, the bags can be left open. The composites would be tested in the event of a problem in the future. Record where all grain is dumped. This works with the retention of samples to provide traceability in the event of a future question. Record what bins are loaded out into specific cars, barges, etc. All of this could reduce the amount of actual testing needed. Be aware of changing market dynamics. There have already been reports of poultry feeders deciding to avoid StarLink for public relations reasons. Sampling and Sample Handling Immunoassay test kits (sometimes called ELISA, quick kits, or strip tests) are the most useful method of checking corn on-site. The PCR (DNA) test, while very precise and sensitive, has to be done in a laboratory over several days. The ELISA kits cost about $100 per 10-test kit package, plus the time and equipment costs. Including sample preparation, they take minutes per test. Between 50 and 400 seeds (depending on detection level) are required for the actual test. For more information on these kits, see the manufacturer websites linked at "GMO Grain Testing Directory", The typical 1- or 2-probe sample (which collects a quart or so of grain) is not adequate for testing low-level factors that occur in some seeds but not others. Detecting StarLink (or other GMOs) is roughly similar to testing for aflatoxin or other mycotoxins. Combine multiple samples from whatever size lot is being tested. The sample size needs are determined more by subsequent sample handling than by the lot size, so testing individual trucks and wagons can be cost and time prohibitive. Use an appropriate sampling plan for the lot or vehicle. The USDA Grain Inspection Packers and Stockyards Administration (GIPSA) has standard plans for wagons, trucks, railcars, barges, and vessels ( biotech, These plans require combining more samples than the typical country grain elevator would take, but for trace level factors, they should be followed The entire sample should be ground, mixed, and then subsampled in the right quantity. This step is the most critical operation of the entire testing process, especially for low-level mixes, and also the most difficult to do in an elevator setting. There are several types of grinders that will work Romer mill, various

4 11/3/00;Revised 11/8/00 4 C:\WINDOWS\Desktop\StarLink\ActionC doc models of burr mills, laboratory hammermills, and home flourmills. Dividing whole kernels to smaller sample will increase the risk of not finding StarLink that is actually present. The lower the actual concentration of StarLink, the more acute this problem becomes, which means the sampling risk is highest in areas with lower levels of StarLink planting. The key is to have at least the equivalent of one StarLink kernel in every possible draw of 400 kernels (0.25% - the detection limit of the test). Some examples: o If the actual level is 0.25%, then a 10-lb sample, if not ground, will have a 37% chance of passing. o If the actual level is 1.0%, the probability of acceptance drops to less than 2%. Grinding the entire sample distributes the GMO material, but also reduces the number of instances in which GMO levels will exceed the sensitivity of the test, therefore detection is likely even if small procedural errors are made. The grinding process will produce the greatest improvements in cases where levels of GMO must be determined and in yes-no detection of very low concentrations. Higher proportions (5% and up) of StarLink probably will be detected even if samples are divided as whole kernels. See for a calculator to determine sample size to grind depending on your willingness to accept risk of future rejection. Table 1 gives examples that show how dependent the process is on concentration and risk. The situation of one StarLink load mixed with many other loads created more effort and risk than cases where a significant portion of the corn was StarLink. Cleaning of sampling and sample handling equipment is very important to prevent carryover into subsequent tests. Each kernel retained the probe, probe box and conveying lines represents 0.05%-0.1% of the gram probe sample. The same is true for mechanical diverter type samples. The amount of carryover can be estimated by first sampling a load of corn, then sampling a load of soybeans that does not contain any corn. The weight of corn kernels in the soybean sample compared to the total weight of sample is an estimate of sample carryover. If corn is found, check for low places in air conveying lines, worn parts on the probe head, grain caught in the collection box. At the testing point, be sure all operators are trained to discard samples completely. A few kernels caught in a moisture tester or on a screen or in a divider are not major concerns for routine grain quality testing, but they are for zero tolerance identification. Again the ratio of the weight of retained kernels compared to the average sample weight is a measure of the percentage carryover. If the entire sample is recombined after regular testing to make the portion for GMO analysis, then each instrument used must be clean; if the GMO portion is divided out first, then the divider and pans are where mixing could occur.

5 11/3/00;Revised 11/8/00 5 C:\WINDOWS\Desktop\StarLink\ActionC doc Grinding equipment is notorious for sample carryover. Grinders can be disassembled for cleaning. As a first check, weigh the amount of ground grain you can get out of the grinder with a complete cleaning. This will give an estimate of potential percentage carryover. Adjust operating procedures as needed. Even food blenders retain some material. Summary Tracing StarLink in existing inventories will be a fairly complex process. It will be important to minimize additional risk by documenting after-harvest corn deliveries. Accurate sampling, sample handling, and testing is resource-intensive, which means atdelivery testing will be costly and, in many cases, impractical. Prequalification and communication will likely be the best practices to use.

6 11/3/00;Revised 11/8/00 6 C:\WINDOWS\Desktop\StarLink\ActionC doc Table 1. Sample size to grind related to StarLink concentration and probability of detection. Concentration (%) Sample size to grind (grams), by probability of detection 95% 99% 99.9% One quart is approximately 800 grams. A typical mechanical probe collects about 750 grams per sample. A 6 hand probe collects grams per sample. Source: USDA, Grain Inspection Packers and Stockyards Administration