Assessment of microbiological and chemical qualities of selected cocoa, tea and coffee brands in Nigerian markets

Abstract

Background: Cocoa, Tea, and Coffee products are consumed worldwide; they are rich in nutrient and, thus, prone to microbial contaminations that could cause food infections and intoxication.

Objective: the objectives of the paper are: To evaluate the microbial and chemical qualities of some popular brands of cocoa, coffee and tea  products in Nigerian market and benchmark it with standard specifications, to determine the products safety for human consumption and proffer solutions on ways to prevent possible food borne hazards associated with these products.

Materials and Methods: This study examined the microbiological and chemical qualities of some brands of these products at the consumer level using standard analytical methods.

Results: Five (50%) of the cocoa products had coliform counts (cfu/g) significantly (p<0.05) higher than  acceptable limits and range from 2.6×101±0.01 to 4.6×101±0.01. The mean total aerobic plate count and fungal counts (cfu/g) cocoa, coffee, and tea were not significantly (p<0.05) different from standard specifications. The microbial isolates include species of Bacillus (59.2%), Staphylococcus(12.0%), Enterobacter(1.6%), Aspergillus(20.0%), Penicillium(14.4%) and Saccharomyces (12.0%). Moisture contents higher than 6% and 3% standard specifications in tea and cocoa products was detected in 7(70%) of tea and 2(20%) of cocoa products respectively. The samples are rich in phenol contents (mg/ml) and contain varying concentrations of manganese, calcium, iron, and copper. Free Radical Scavenging (DPPH) activity of 6.2±0.01 to  16.3±0.02μg/ml was detected in the samples.

Conclusion: Some cocoa products contain unacceptable levels of coliforms, the high moisture contents above 3 and 6% standard specifications in some cocoa and tea products could encourage the proliferation of  mycotoxigenic moulds and pathogenic bacteria to hazardous levels. The use of good raw materials, compliance to good manufacturing practices (GMP) and apt storage are advocated.

Keywords: Chemical qualities, Cocoa, Coffee, Microbial qualities,  Mycotoxigenic moulds, Tea