I have been receiving calls regarding where grain can be tested for transgenic traits. More and more, the grain handling industry is treating transgenic grain as an identity preserved (IP) commodity. In order to segregate non-transgenic corn and soybean grain, grain elevator managers want to know whether an incoming load of grain has any transgenic grain mixed with non-transgenic grain. Ideally a qualitative transgenic detection test is needed that will provide reliable results in the time it takes a truckload of grain to move from the scale and probe to the dump pit. Perfecting such a test with statistically accurate results is a monumental task. The grain industry is not there yet, and can only provide specific tests for specific transgenic traits.

A number of tests methods are available for testing each having pros and cons associated with the methodology (Table 2). In general there are two scientific methods for detecting transgenic field crops. One method involves testing for specific protein that has been incorporated through biotechnology into a crop; the other is based on detection of DNA sequences inserted in the crop.

Farmer testing of transgenic traits can easily be accomplished using lateral flow strips (Table 3). Results with Lateral flow test strips are qualitative (yes or no for presence of transgenic trait). A number of companies produce these strips and they can be easily obtained (Table 4). Currently, there is no single, rapid or inexpensive test to verify whether a crop or crop sample is free of transgenic traits. Before purchasing a commercial test kit, it is best to know the specific crop and transgene to be tested.

Table 1. Wisconsin laboratories that conduct tests for transgenic traits (websites verified 15 October 2003).
Bioassays only Wisconsin Crop Improvement Association 1575 Linden Drive Madison, WI 53706 (608) 262-1341 Fax: (608) 262-0210 www.wisc.edu/wcia/	All Methods BioDiagnostics, Inc. 507 Highland Drive River Falls, Wisconsin 54022 (715) 426-0246 Fax: (715) 426-0251 www.biodiagnostics.net/index.html

Table 2. Methods to test for transgenic traits, their cost, duration ease of use and expected results.
Method	Tests for	Cost/Sample	Duration	Ease of Use	Results
Bioassay (For herbicide resistant traits)	Tolerance to chemical	$10-12	5-7 days	Moderate; requires familiarity with laboratory practices	Quantitative measure for presence of herbicide resistance
ELISA (Enzyme-Linked Immunosorption Assay)	Protein	$75-100^a	2-4 days^d	Moderate; requires familiarity with laboratory practices and some specialized equipment	Quantitative measurement of protein levels
Lateral Flow Strip	Protein	$8-10^b	10-20 minutes	Little training and no sophisticated lab equipment required	Qualitative measurement of presence or absence of target protein analyte
PCR (Polymerase Chain Reaction)	DNA	$200-600^ac	5-14 days^d	Difficult; requires specialized equipment and training	Qualitative/semi-quantitative measurement of levels of target sequence
Southern Blot	DNA	$100-300	4-6 days	Difficult; requires specialized training and equipment including radioactive materials	Identifies specific DNA sequences
^aEstimated cost of analysis performed by a commercial testing laboratory ^bEstimate cost of material to perform on-site analysis, excluding labor ^cPrices for PCR tests vary widely and depend on the nature of the test being performed (e.g., screening versus quantitative assessment) ^dEstimate of time required to have samples analyzed by a commercial testing laboratory. Sources: Gene Amberson and www.croplifeamerica.org/public/issues/biotech/detecta.pdf (website verified 15 October 2003)

Table 3. Transgenic detection kits submitted to Grain Inspection, Packers and Stockyards Administration (GIPSA) of the Federal Grain Inspection Service by kit manufacturers. Kit performance as claimed by the manufacturer was verified by GIPSA.
Company	Test Kit	Part Number	Event/Protein Analyte	Test Sensitivity	Test Format
Agdia, Inc.	Roundup Ready® ImmunoStrip^(TM)	STX- 74000	Roundup Ready Protein CP4EPSPS	1 in 800 corn kernels	Lateral Flow Strip
EnviroLogix Inc.	Cry9C ELISA Plate Kit, High Sensitivity Protocol	AP 008	StarLink/Cry9C	1 in 10,000 corn kernels	Microtiter Well Plate Assay
EnviroLogix Inc.	Cry9C ELISA Plate Kit, Rapid Protocol	AP 008	StarLink/Cry9C	1 in 2,400 corn kernels	Microtiter Well Plate Assay
EnviroLogix Inc.	QuickStix ^(TM) Strips for Cry9C (StarLink)	AS 008 BG	StarLink/Cry9C	1 in 800 corn kernels	Lateral Flow Strip
EnviroLogix, Inc.	QuickStix ^(TM)Strips for Roundup Ready® in Soybeans	AS 010 BG	Roundup Ready® protein,CP4 EPSPS	1 in 1,000 soybeans	Lateral Flow Strip
EnviroLogix, Inc.	QuickStix ^(TM) Strips for Roundup Ready® in Corn	AS 010 BG	Roundup Ready® protein,CP4 EPSPS	1 in 200 corn kernels	Lateral Flow Strip
EnviroLogix Inc.	QuickStix ^(TM) Kit for YieldGard^® Rootworm Bulk Seed	AS015BG	Cry3Bb	1 in 200 corn kernels	Lateral Flow Strip
Neogen Corporation	Agri-Screen CP4 Strip Test	8005	CP4 EPSPS protein of Roundup Ready soybean and Roundup Ready corn (NK603)	1 in 800 corn kernels 1 in 1,000 soybeans	Lateral Flow Strip
Neogen Corporation	Agri-Screen Qualitative Cry9C Test	8002a	StarLink/Cry9C	1 in 800 corn kernels	Microtiter Well Plate Assay
Neogen Corporation	Agri-Screen Cry9C Strip Test	8003	StarLink/Cry9C	1 in 800 corn kernels	Lateral Flow Strip
Strategic Diagnostics, Inc.	^GMO^TM Bt9 Maize Kit	7110030	StarLink/Cry9C	1 in 10,000 corn kernels	Microtiter Well Plate Assay
Strategic Diagnostics Inc.	^GMOQuick ^TM Bt9 Test Kit	7110020	StarLink/Cry9C	1 in 800 corn kernels	Microtiter Well Plate Assay
Strategic Diagnostics Inc.	Trait Bt9^TM	7000034	StarLink/Cry9C	1 in 800 corn kernels¹	Lateral Flow Strip
Strategic Diagnostics Inc.	Trait Bt9^TM	7000003	StarLink/Cry9C	1 in 800 corn kernels	Lateral Flow Strip
Strategic Diagnostics Inc.	Trait Bt9^TM	7000012	StarLink/Cry9C	1 in 800 corn kernels	Lateral Flow Strip
Strategic Diagnostics, Inc.	Trait^TM Cry3Bb Corn Grain Test kit	7000041	Cry3Bb (YieldGard Rootworm®)	1 in 800 corn kernels	Lateral Flow Strip
Strategic Diagnostics, Inc.	Trait RUR Bulk Soybeans 5-Minute Test Kit	7000014	Roundup Ready Soybeans/CP4 EPSPS	1 in 1,000 soybeans	Lateral Flow Strip
Strategic Diagnostics, Inc.	Trait RUR NK603 Corn Grain 5-Minute Test Kit	7000011	Roundup Ready Protein CP4 EPSPS	1 in 800 corn kernels	Lateral Flow Strip
Strategic Diagnostics Inc.	Trait^TMBt1F Corn Grain Test Kit	7000018	Cry1F (Herculex^TM)	1 in 600 corn kernels	Lateral Flow Strip
^1/ Sensitivity of 1 in 400 kernels requires a 10-minute development time. Sensitivity of 1 in 800 kernels requires a 20-minute development time. Source: http://www.usda.gov/gipsa/ Click on "Tech Services/Support" (website verified 15 October 2003)/

Table 4. Sources for Lateral flow test strips (websites verified 15 October 2003):
Envirologix, Inc. 500 Riverside Industrial Parkway Portland, ME 04103 (866) 408-4597 www.envirologix.com	Strategic Diagnostic, Inc. (SDI) 111 Pencader Drive Newark, Delaware 19702 (800) 544-8881 www.sdix.com
Neogen, Inc. 620 Lesher Place Lansing MI 48912 (800) 234-5333 www.neogen.com	Agdia, Inc. 30380 County Road 6 Elkhart, IN 46514 (800) 62-AGDIA www.agdia.com/