Sensitivity of nutritional and microbial content of food wastes to drying technologies

Abstract

The recovery of food waste fraction of municipal solid waste and value addition has not received attention despite the high composition in the solid waste stream. This paper presents a study on the drying of food waste, the safety and nutritional quality of the dried food waste as an alternative feed ingredient to maize in the poultry feed production. Food waste was dried at different temperatures using solar, a halogen oven and conventional oven dryers. The dried food waste samples were analyzed for microbial load, aflatoxins, heavy metals, and nutritional quality. The drying of the food waste to less than 10% moisture content was between 22 h (2–3 days) for the solar dryers and 4 -10 h for the halogen and conventional oven dryers. For the different dryers, the macronutrients (protein, carbohydrate, and lipid) of the dried food waste were lower than the fresh food waste, but the nutritional quality meets the requirement for poultry feed quality. Toxicity of the cadmium, arsenic, aflatoxin and microbial levels in the dried food waste was lower compared to that of the fresh food waste and within the poultry feed guideline values. The oven drying at temperature 155 °C retained the macronutrients and reduced the toxins in the dried food waste, and therefore was the optimum for dehydration and converting food waste into poultry feed.

Keywords

• Food waste drying
• Municipal solid waste
• Poultry feed
• Food waste nutrients
• Microbial load
• Food waste toxicity