Abstract:
Coffee that has been poorly processed and stored can be contaminated with moulds especially
Aspergillus and Penicillium species which have been reported to produce mycotoxins
including Ochratoxin A. This study was done to assess the moulds and Ochratoxin A
contamination of green coffee beans from Estates and Cooperative societies located in the
main coffee growing zone in Nyeri County. The levels of moisture content, sucrose, caffeine
and chlorogenic acids content, mould contamination and Ochratoxin A levels in green coffee
beans processed by wet and dry methods was determined. The moisture content of the coffee
samples were determined by dry oven method, sucrose, caffeine, chlorogenic acids and
Ochratoxin A levels by use of HPLC and moulds enumeration by serial dilution technique.
The percentage moisture content of coffee samples from Estates and Cooperative societies
ranged between 7.06% - 8.47% and 6.85% - 9.27%, respectively. The results showed no
significant difference on the level of moisture content in the coffee samples from Estates and
Cooperative societies. The sucrose, caffeine and chlorogenic acids content of coffee samples
from estates ranged between 6.45% - 8.37%, 1.06% - 1.26% and 4.52% - 6.88%
respectively. For coffee samples from Cooperative societies, the sucrose, caffeine and
chlorogenic acids content ranged between 5.93% - 8.31 %, I .07% - 1.30% and 4.31 % -
7.72%, respectively. Significant (p :S 0.05) variations were observed among the samples from
different Cooperative societies and Estates in terms of sucrose, caffeine and cblorogenic acid
contents of the coffee beans. Mould counts of coffee samples from cooperative societies and
estates were found to be between 1.46 x 103CFU/ml to 6.0 x 101 CFU/ml. More dry processed
coffee samples were contaminated with moulds as compared to wet processed coffee samples.
Ochratoxin A was not detected in all the coffee samples. It can be concluded that coffee
samples collected from estates and cooperative societies were not contaminated with
Ochratoxin A even though some showed low levels of mould contamination.
