Bacterial and heavy metal contamination in selected commonly sold herbal medicine in Blantyre, Malawi.

Background: There has been an increase in use of herbal medicine worldwide. It is either used as a stand-alone or complementary therapy to conventional medicine due to past good experience, poverty and family traditions. In Malawi, there are no regulations governing the supply, acquisition, marketing and quality enforcement of herbal medicine. This compromises its safety thereby exposing consumers to avoidable bacteria and heavy metals leading to various adverse health effects. Methods: Cross-sectional laboratory experiments were conducted to determine bacterial and heavy metal contamination of herbal medicine commonly sold in Blantyre, Malawi. A total of 47 samples which were in three formulations namely liquid, powder and tablet were used in the experiments. 29 samples were used for bacterial limit tests and 18 samples were used for heavy metal analysis. Bacterial contamination was determined by streak plate method and biochemical tests while heavy metals were determined by atomic absorption spectroscopy. Descriptive statistics and t-tests were calculated using Microsoft excel and SPSS software programs. Results: Twenty out of the 29 samples (68.9%) were contaminated with Bacillus, coagulase negative Staphylococcus, Klebsiella, Enterobacter, Citrobacter and other-Coliform bacterial species. Most isolated microorganism was Citrobacter spp. (30%), followed by Bacillus spp. (25%). Out of 20 contaminated samples, 75% were contaminated with coliforms. From these 75% which were contaminated with coliforms, 93.3% of them exceeded WHO regulatory limit (103 CFU/g for enterobacteria). Although liquid samples had the highest level of bacterial contaminants, the count was not statistically different from other formulations (P = 0.058). For heavy metals, lead and cadmium were detected and 67% of the samples had lead levels exceeding regulatory limits. Conclusion: Levels of bacterial and lead contamination in herbal medicine from Blantyre markets are far above acceptable limits set by WHO and Canadian guidelines. The use of these herbal medicines is a major risk to the health of consumers.

Microbiological quality of traditional and improved kiln smoked catfish (Clarias gariepinus; Pisces; Clariidae) in Lake Chilwa Basin.

Microbiological quality of smoked catfish (Clarias gariepinus) locally known as Mlamba was assessed in this study where traditional and improved smoking kilns were used to smoke fish. Catfish is common fish caught in abundance in the Lake Chilwa basin, and the fish is usually smoked to reduce postharvest losses and increase shelf life. Samples were collected in sterile polythene bags, well labeled, and collected in cooler boxes transported ready for laboratory analysis. One gram representative sample was obtained aseptically from the muscle of the fresh and smoked catfish (Mlamba) samples. The samples were grounded, and fourfold serial dilutions (10-1-10-4) of the homogenized samples were made using sterile distilled water. Fish samples were analyzed for total plate count (TPC), Escherichia coli counts, and pathogenic organisms (Salmonella) following the methods prescribed by AOAC (Official methods of analysis, Association of Official Analytical Chemistry, Arlington, VA, 2000). Each analysis was carried out in triplicates. There were significant differences (p = 0.05), with respect to total viable bacterial counts between traditional kiln smoked and improved kiln smoked catfish (5.6 × 106 cfu/g, 1.9 × 106 cfu/g, respectively). Traditional kiln smoked catfish harbored significantly higher total viable counts as well as a higher population of E. coli compared to improved kiln smoked catfish. However, for both types of smoking kilns there were detected levels of pathogenic bacteria Salmonella with traditional kiln smoked catfish containing 2.1 × 104 cfu/g which were significantly higher than amount found in improved kiln smoked catfish (1.5 × 104 cfu/g; p = 0.05). Salmonella is a microbe of public health importance and has implications on the handling and source of the fish.