**4. Literature review**

The purpose of this literature review is to provide a background on challenges of waste, waste controlling mechanism and applicability of waste controlling strategies across a variety of industries. Since this understanding will help determine which waste controlling strategies and principles are appropriate for implementation within the food manufacturing industry, and detail topics discuss in this section are for history of waste minimization in manufacturing industry, lean manufacturing philosophy, six sigma and Malcolm Baldrige National Quality Award (MBNQA) principle, tools and technique in manufacturing industries as whole as well as a detailed summary of the literature concerning improvement and competitiveness problem of Ethiopian food processing industry. Though the principal sources of this information included company reports, published literature in textbooks and journals were incorporated.

#### **4.1 Wastes in the food processing sector**

Food loss should mean the decrease in edible food mass throughout the food chain. Food losses take place in production, postharvest and processing stages in the food supply chains. Since a division is to be made whether the loss of resources happens in the early stages of the food supply chains (FSC) or the resource was wasted by the action of the retail sector or consumers. Though in the first case, the problems can call about food losses, while in the latter case about food waste. The food losses can be avoided by a correct action, e.g. by maintaining the cold supply chain or ensuring correct storage conditions for products. Since the food loss also occurs if the product that was originally intended for human consumption is recovered in the form of feed, fertilizer or energy [10, 11]. Besides the waste and food waste is more comprehensive and it includes all resources that are lost in the different sectors of the food supply chain, and will include also those parts that were originally not intended for human consumption.

#### **4.2 Waste minimization strategies and mechanisms**

The waste is an important issue that should be treated in such a way that the benefits achieved from that will be in both environmental and social aspects. As in manufacturing industries, waste management is key issues to greater opportunities for waste recovery and diversion of waste from landfill, and services suitable to

businesses. Though according to [10] shows that waste management is favoring reuse and recycling before land filling, with the main idea of environmental sustainable society.
