TABLE 1.

Production of aflatoxins B₁ and G₁ by representative West African and North American S strain isolates in liquid media containing either ammonium or urea as the sole nitrogen source

Test	Origin	Isolate	N concn (mM)	Result in NH4 or urea mediuma
				Aflatoxin B1 (μg)		Aflatoxin G1 (μg)		Final pH		Mass (g)
				NH4	Urea	NH4	Urea	NH4	Urea	NH4	Urea
1	Benin	BN008R	45	6 B	940 A	0 B	270 A	3.2 B	3.1 B	790 B	700 B
			100	16 B	1,400 A	0.04 B	1,900 A	2.3 C	3.6 A	830 B	1,000 A
2	Benin	BN038G	45	400 E	1,900 D	6 E	240 D	2.4 E	3.4 DE	850 D	770 E
			100	370 E	2,000 D	4 E	290 D	2.4 DE	3.9 E	730 E	870 D
3	Benin	BN026G	45	35 G	240 F	0.9 G	71 F	2.3 H	3.3 G	970 F	620 G
			100	13 G	180 F	0.7 G	69 F	2.4 H	4.0 F	990 F	760 FG
4	Benin	BN040B	45	30 J	890 I	1 J	210 I	2.2 K	3.3 J	990 I	690 J
			100	28 J	1,900 I	1 J	930 I	2.4 K	3.9 I	910 I	920 I
5	United States	YV2-19	45	620 L	1,400 L	0	0	2.5 M	3.9 L	310 M	580 M
			100	780 L	1,600 L	0	0	2.5 M	4.1 L	310 M	890 L
6	United States	LA2-5	45	940 N	220 O	0	0	2.4 P	3.3 O	580 P	950 O
			100	900 N	380 O	0	0	2.5 P	4.6 N	450 P	1,100 N
7	United States	MS22-41	45	830 Q	940 Q	0	0	2.5 S	3.4 R	300 S	680 R
			100	620 Q	1,200 Q	0	0	3.0 RS	4.2 Q	260 S	960 Q
8	United States	AL3-22	45	680 T	590 T	0	0	2.7 V	3.5 U	250 V	640 U
			100	1,100 T	820 T	0	0	2.5 V	4.0 T	360 V	870 T

^aResults are averages of three replicates. Values for a variable within a test followed by a common letter are not significantly different (P = 0.05) according to Fisher’s least significant difference test. Each Benin isolate originated from a separate agricultural field. Isolates YV2-19, LA2-5, MS22-41, and AL3-22 originated from agricultural fields in Arizona, Louisiana, Mississippi, and Alabama, respectively.