Bacteriological examination of herbal mixtures consumed in Awka, Anambra State, Nigeria

Herbal mixtures are widely consumed in the world over for therapeutic and health maintenance purposes. However their quality and safety are often unregulated, raising concerns about microbial contamination. This research investigated the bacteriological quality of 10(ten) herbal mixture samples purchased from various retailers in Awka. The research aimed to determine the bacterial loads, isolate, characterize and identify bacterial species present using standard microbiological methods. The results revealed a significant and concerning level of microbial contamination across most herbal samples, with several exceeding the World Health Organization's (WHO) permissible limits of 10⁴ cfu/ml for non-sterile herbal medicinal products. The mean pH values of the samples ranged from 2.93±0.076 to 5.72±0.076. The study identified high bacterial loads, with THBC (Total heterotrophic bacterial count) reaching up to 2.45 X 10³ log cfu/ml. The presence of coliforms was widespread, with TCC (Total coliform Count) and TFCC (Total faecal coliform count) loads reaching up to 1.99 X 10³ and 1.88 X 10³ log cfu/ml, respectively. Furthermore, key pathogens were detected, which include Staphylococcus aureus (up to 1.77 X 10³ log cfu/ml), Salmonella (up to 1.96 X 10³ cfu/ml), and Shigella (up to 1.75 X 10³ cfu/ml). The identified isolates, which include Salmonella spp. and Escherichia coli, were characterized as Gram-negative rods or Gram-positive cocci. In vitro pathogenic profiling confirmed their virulence, whereby all tested strains showed β-hemolysis on blood agar and a positive reaction to the Congo red binding assay. The consistent absence of essential labeling information, such as manufacturing and expiry dates, across all samples further revealed a critical lack of quality control and regulatory oversight. Collectively, these findings showed a significant risk associated with the consumption of these herbal mixtures in Awka, necessitating stricter regulatory oversight and quality control measures for these consumed products.