Microbiological safety and quality of dried cassava chips and flour sold in the Nairobi and coastal regions of Kenya

Abstract

Cassava (Manihot esculenta Crantz) is rich in carbohydrates and is the third most important source of calories, in the tropics. The handling and processing practices of cassava roots expose them to microbial contamination. The objective of this study was to assess the level of contamination of cassava products that are in markets so as to establish the safety for human consumption. Samples from Nairobi and Coastal region of Kenya were evaluated for: total count, Staphylococcus aureus, total coliforms, yeast and mould and E. coli to establish their safety and quality for human consumption. Results for dried cassava chips showed; TVC 5.16-8.04 log cfu g^-1; 4.81-7.21 log cfu g^-1, mould 1.00-3.86 log cfu g^-1; 1.00-3.28 log cfu g^-1 and Staphylococcus aureus 2.69-4.36 log cfu ^-1; 2.90-4.71 log cfu ^-1 for Nairobi and Coastal region respectively. Cassava flour was; TVC 5.66-7.67 log cfu g^-1; 5.92-8.12 log cfu g^-1, mould 1.00-6.73 log cfu g^-1; 2.65-5.08 log cfu g^-1, Staphylococcus aureus 3.77-5.79 log cfu g^-1; 1.00-5.73 log cfu g^-1, and coliforms 0-6.34; 2.00-6.27 log cfu g^-1 for Nairobi and Coastal regions respectively. One sample tested positive for presence of E. coli. Eighty seven percent of cassava flour and 77% of dried cassava chips samples were confirmed for presence of Staphylococcus aureus. There was a significant (P<0.05) difference in the microbial counts among the dried cassava chips samples and the cassava flour samples from markets in Nairobi and Mombasa. Results indicate excessive manual and poor post-harvest handling practices of the products hence, their poor quality and non-safety for consumption.

Key Words: Chips, contamination, Manihot esculenta