Microbiological Evaluation of Ready-to-Drink Tigernut Drinks Sold within Port Harcourt Metropolis, Rivers State, Nigeria

Aims: Tigernut drink are made from tigernut tubers (Cyperus esculentus L.) and rich in nutrients. This drink is locally produced and widely consumed in Nigeria irrespective of social status. This study is aimed at evaluating the microbial quality and physicochemical property of tigernut drinks sold within Port Harcourt metropolis.

Methodology: Thirty (30) samples of freshly prepared and packaged tigernut drinks were randomly purchased from different vendors in five locations of Port Harcourt metropolis (Agip Estate, Abuja Campus (Uniport), Choba, Mile 1 and Mile 2 Markets). The samples were analyzed using standard microbiological and physicochemical methods. SPSS (Statistical Package for the Social Sciences) was used to analyze the data.

Results: Results obtained showed that the pH of the samples ranged from 4.2 to 4.6 while the total heterotrophic bacterial count ranged from 6. 54-6.74 log10 CFU/mL. Total fungal count of tigernut drinks ranged from 6.0-6.2 log10 CFU/mL. A total of nine (9) bacterial genera namely Staphylococcus sp. (37.3%), Escherichia sp. (21.3%), Salmonella sp. (12%), Pseudomonas sp. (12%), Klebsiella sp. (4%), Bacillus sp. (4%), Micrococcus sp. (4%), Enterobacter sp. (2.7%) and Corynebacterium sp. (2.7%) were isolated from the samples. Six (6) fungal genera were also encountered in the drink sampled which include Rhizopus sp. (1.4%), Saccharomyces sp. (4.4%), Aspergillus sp. (30.9%), Fusarium sp. (26.5%), Penicillium sp. (30.9%) and Candida sp. (5.9%). The result revealed that Staphylococcus sp. had the highest percentage of occurrence (37.3%) followed by E. coli (21.3%), while Enterobacter sp. (2.7%) and Corynebacterium sp. (2.7%) recorded the least. Among the fungal isolates, Aspergillus sp. and Penicillium sp. had the highest percentage of occurrence (30.9%) whereas Rhizopus sp. had the least (1.4%). The results of this study revealed that all the samples from the five (5) locations were heavily contaminated with pathogenic microorganisms and found not suitable for human consumption based on the standard recommended by National Agency for Food and Drug Administration and Control (NAFDAC). NAFDAC stipulated that mesophilic aerobic count of locally prepared beverages should be < 5.0 log10 CFU/mL.

Conclusion: The huge contamination recorded in all the samples irrespective of the location could be linked to poor hygienic levels during processing. Therefore, good manufacturing practices, public health enlightenment campaign and strict regulations from relevant agencies are recommended to avoid foodborne infections, diseases and possible deaths which could result from consumption of such contaminated tigernut drinks.