Safety of traditional leafy vegetable powders from Lindi in Tanzania

Abstract

Postharvest losses in the fruits and vegetables sector remain a major problem in the world, and especially in Sub Saharan Africa. Up to 50% of fruits and vegetables produced in developing countries is lost in the supply chain between harvest and consumption. Though WHO recommends consumption of at least 400 grams of fruits and vegetables daily, the actual consumption is much less. Two billon people are still suffering from micronutrient deficiencies and almost 800 million from caloric deficiencies on a global scale (Achadi et al., 2016). Lindi in Tanzania, is among the most affected in the country. To combat this problem, one of the interventions that can be used to address the problem is to preserve vegetables. In this study, three types of Traditional Leafy Vegetables (TLVs) - Amaranths (AML), Sweet potato (SPL) and Cassava leaves (CAL), grown in Ruangwa and Nachingwea Districts in Lindi Region were carefully collected from Home Gardens (HG) and Low Land (LL). They were solar dried and made into powders that had been optimized for Iron content. The vegetable powders were then mixed with water and spices to make four (4) soup formulations. The safety of these products had not been determined. This study was therefore conducted to evaluate the microbiological quality (Total plate count and E. coli) of the vegetable powders. Significant differences (p≤0.05) in microbial load among raw vegetables were observed. Sample CAL had the highest load (3.67 x 102) whereas sample SPL had the lowest (3.15 x 102). The microbial load between the two sites also differed significantly (p<0.05). However, there were no significant differences (p≥0.05) in microbial quality of the vegetable powders, all of which were below the TBS standards. No E. coli was detected in any of the samples studied. The absence of E. coli in the samples indicates appropriate handling of the vegetables. With the year 2021 being the International year of fruits and vegetables, it is crucial to raise awareness of their role in human nutrition, food security and health. Consuming sufficient fruits and vegetables is important as a source of micronutrients and support the immune systems. They also lower risk of depression and anxiety, obesity and non-communicable diseases; promote gut health (UN news, 2020). Thus, solar dried TLVs and the developed products are recommended for use due to their safety and quality. These TLVs are a potential source of micronutrients if properly processed and utilized.