Assessment of effect of post-harvest treatment on microbial quality of honey from parts of Ghana

Abstract

The impact of post-harvest treatment on the microbial quality was assessed in samples of honey produced in parts of Ghana to identify sources of contamination and understand how such contamination can be managed. Honey was sampled from three regions in Ghana: Greater Accra, Ashanti, and Brong Ahafo. For each region, honey was collected from the producer (i.e., pre- and post-processing) and the retailer. This was done for ten different producers and their corresponding retailers, generating a total of 90 honey samples. Microbial analysis indicated that some honey samples were positive for total viable counts (TVC) and out of the four species of microbes considered, three species were detected in the samples. These are Fecal coliform species (sp.), Clostridium sp., and Staphylococcus sp. Salmonella sp. was not detected in any of the samples analyzed. The investigation revealed that 83% of the honey sampled was positive for TVC and 13% of the samples had TVC more than 100 CFU/mL. Honey samples collected directly from the producers (both pre- and post-processing) had 53% of the samples testing positive for TVC whereas 100% of the honey sampled at the retail points tested positive for TVC, indicating postharvest microbial contamination of honey. The data suggested that the microbial contamination of honey can be prevented or tremendously reduced if appropriate regulation mechanisms can be put in place for honey production and marketing. Gamma irradiation with a cobalt-60 source at a maximum dose of 10 kGy was effective in decontaminating the honey. Honey samples were analyzed for selected physicochemical characteristics before and after irradiation. The differences (p = 0.05) observed could be linked to the effect of post-harvest treatment of honey rather than irradiation. For instance, there were higher levels of apparent sucrose and ash content in honey collected from retailers relative to honey sampled at the producers’ points at all irradiation doses, confirming that post-harvest handling has more impact on honey quality.