Safety and quality of organically grown cloves (syzigium aromaticum) and black pepper (Piper nigrum l.) in Tawa Ward, Morogoro-Tanzania

A Dissertation 2019

Participatory Action Research approach was used in this study involving organic spice farmers from Tawa Ward within Morogoro region, researchers from Sokoine University of Agriculture and Sustainable Agriculture Tanzania organization. Harvesting and post- harvest handling practices by clove and black pepper organic farmers in Tawa Ward were assessed. Five villages were visited, 107 organic farmers were interviewed, 34 among them inspected and provided samples for analysis. Fungal quality in association to post- harvest practices and moisture content was evaluated. Average moisture content was 18.7% (clove) and 12.3% (black pepper) in dry weight basis. It was observed that, farmers use experience and color change to determine moisture content and therefore fail to achieve the recommended moisture content of 12% as per Tanzania Bureau of Standards. Farmers in this study practices mixed farming in farm sizes of less than 5 hectares and harvest less than 100 kg of spices annually. However, poor drying and storage methods, mixing spice batches and attempts to treat spoiled spices were noticed as critical points that compromises safety and quality. Fungi were isolated by using spread plating method in PDA and V8 medias. Fungi identification were based on macro and microscopic characteristics. Black pepper samples were found to be contaminated by Aspergillus, Rhizopus, Penicillium and Fusarium fungal species at level of 2200 - > 30 000 cfu/g. Clove sample were contaminated by Aspergillus and Rhizopus species at level of 100-60°C fu/g in 46% of the samples. Longer storage time and mixing spices with previous batches during storage showed higher influence on level of fungal contamination. Also, this study measured levels of three heavy metals; Lead, Cadmium and Chromium in the spice samples. Levels of all three metals were found to be below permissible levels with average of 0.32±0.22mg/kg (Lead), 0.14±0.06mg/kg (Cadmium) and 0.33±0.16 mg/kg (Chromium). Detection of Lead in 10% of the sample was highly related to poor storage. This study recommends improvement in post-harvest handling approaches in order to ensure safety of the spices from Tawa Ward.