Jl. Ferreira et al., Detection of preformed type A botulinal toxin in hash brown potatoes by using the mouse bioasssay and a modified ELISA test, J AOAC INT, 84(5), 2001, pp. 1460-1464
A foodborne illness caused by type A toxin-producing Clostridium botulinum
was investigated by using the standard mouse bioassay and a rapid invitro t
est for toxin detection. The patient, who consumed improperly stored hash b
rown potatoes that contained the preformed toxin, was diagnosed with type A
botulism. C. botulinum type A toxin was detected in the hash brown potatoe
s as well as in the tryptone-peptone-glucose-yeast extract (TPGY) medium su
bcultures of this food using the mouse bioassay and an amplified ELISA tech
nique. The mouse bioassay revealed preformed toxin at 10 000 minimum lethal
dose (MLD)/g uncooked product and the amplified ELISA an equivalent 50 000
MLD/g. The cultural toxin from the uncooked product killed mice at the 10(
6) dilution and a modification of the ELISA procedure was positive at the 1
0(3) dilution. Cooked food obtained from the consumer's waste can contained
100 MLD/g and the ELISA was also positive at the same dilution of the prod
uct. The culture of the cooked product obtained from the waste can was leth
al for mice at the 10(7) dilution and positive using the modified ELISA at
the 10(4) dilution. The unmodified amplified ELISA method indicated a toxin
level of approximately 1 ng/mL (equivalent to 5 x 10(5) MLD/mL) in diluted
culture fluid from the uncooked food and the culture of cooked food obtain
ed from the waste can. The hash brown potatoes were negative for types B, E
, and F preformed and cultural botulinal toxins using both assays.