| dc.description.abstract | Mycoflora of stored maize and maize products was investigated
during November 1990 - July 1991. A total of 214 samples of maize
kernels and flour were randomly collected from the kiosks and shops
within Nairobi for analysis. Out of the 214 samples. 37 were maize
kernels. 40 were bagged maize flour. 58 were "Ugali" brand maize
meal, 74 were "Jogoo" brand maize meal, and 5 were pounded maize
kernels. Malt extract agar medium was used for the Isolation of the
mycoflora. Four fungal genera and sixteen species were isolated from
maize and maize products (maize kernels. pounded maize kernels.
bagged flour and two brands of packet maize flour namely "Jogoo" and
" Ugali). Some of the most important fungal species isolated were
Aspergillus flavus, Fusarium moniliforme. Penicillium stoloniferum.
Penicillium cyclopium and Penicillium funiculosum.
All the 214 samples were contaminated with potential toxigenic
fungi. The fungal populations encountered in the samples increased
with time as the mandatory expiry date on the package material
approached. The higher the moisture content of the sample. the
greater the fungal colony counts recorded in the specimen. Enumeration of the various to:icigenic fungi showed that their
presence in whole grain maize and its products did not necessarily
indicate the presence of mycotoxins. Similarly. lack of visible fungal
colonies did not connote that the products were mycotoxin-free.
The incidence and levels of mycotoxins produced by the isolated
fungi in the products were also determined. Samples of bagged flour.
packet flour ("Jogoo" and "Ugalt" brands) countained aflatoxins B1
and B2 (0.4 - 20.0/-1g/kg). About 5 percent of these samples were
contaminated with zearalenone (2.500 - 5.000 /-1g/kg);ochratoxin A
was detected in 96.6 percent of the samples at concentrations of
50.0 - 1.500 j.lg/kg far in excess of the pernfissible level (1.0 - 50.0
j.lg/kg) in many countries.
Contamination of maize kernels and their products probably
occurs either at farm. storage. and transportation levels. There was
no significant difference in contamination of the different brands of
flour obtained from different study zones. Contamination by
zearalenone and aflatoxins among bagged flour. "Jogoo" and" Ugali"
maize meal brands was non significant. However. there was a
significant difference in contamination by ochratoxin A among the
three brands of flour (F = 5.19. p<0.05).
It is concluded that maize and maize products in Kenya are
contaminated by various types of toxigenic fungi. The presence of
several other toxigenic moulds (e.g.. Penicillium islandicum.
Aspergillus tetras, Aspergillus clavatus. e.t.c.) Indicated that. there
could be additional mycotoxins that may be present in our maize
products. The occurrence of ochratoxin A and zearalenone in maize
kernels and flour is significant and therefore appears to be of real
concern. The data clearly suggest that rigorous monitoring of
mycotoxins in maize and maize product in Kenya should be pursued. | en |
