Waste in the food industry mainly includes organic residues of the raw material after processing. Production of wastes during processing of several products is not desirable as it significantly deteriorates the quality of finished products if incorporated. Disposal and utilization of waste materials is a difficult task due to its poor biological stability, high water activity, poor oxidative stability, pathogenicity and optimum enzymatic activity. Wastes generated by different food industries can be quantified on the basis of their respective production levels. Unlawful disposal and utilization of untreated or poorly treated waste without following the regulations of handling, transport and disposal of waste material causes serious threats on environment (Russ & Pittroff, 2004). When raw material and other supportive ingredients enter the production line then several types of products are produced including desired finished product, product-specific waste and non-product-specific waste. Product-specific waste accumulates in the processing line through various processing steps during the extraction of desired components. After extraction of desired components during processing of raw materials there are certain other useful constituents that remain in the remaining materials. Some common examples of this type of waste include consumed grains during the production of beer and waste generated by slaughter houses. This waste contains plentiful amount of organic compounds due to which its disposal is quite difficult.
Several types of by-products and waste materials are generated during the slaughtering like manure, rumen and intestinal material, liver, blood, feathers, bones, fat and wastewater. Slaughtering is carried out in a very centralized way in most of the developed countries. The consumers in the developed countries mostly prefer lean meat or some offal including kidneys, brain, tongue and sweetbread. Moreover, carcasses are mostly cooled and deboned in the abattoir and then sent to the retail outlets. Huge amount of waste is left in the slaughterhouse that contains hides, bones, esophagus spleen and lungs. This waste material can be carefully disposed-off or can be further utilized to prepare different by-products after proper treatment.
Contrarily, in the developing countries inedible offal are discarded on the nearby land of processing plants or slaughter houses without any further treatment which may lead to several environmental and health hazards (FAO, 2008). There is a need to reuse offal. Fatty tissues can be converted into edible fat and some other tissues can also be processed into a number of products including composite bone-cum-protein meals, meat meal, blood meal and bone meal. With proper treatment and processing, these by-products can be further utilized in feed-industry, pet food, fertilizer industry and human consumption.
Modern slaughter houses are well equipped with several facilities including running water, power, steam, refrigeration, transport etc. However, large variety of slaughtering sites can be seen in developing countries. It varies from simple slabs to very modern abattoirs Moreover, some modern meat processing plants are also imported but often without the facilities of proper waste treatment.
Most of these shambles lack in proper sanitation systems and cause serious health threats to the nearby areas. In addition, old slaughterhouses have no proper arrangements for discharge of blood and wastewater. This blood normally coagulates in the drains and causes off-odor and several environmental hazards (Kaasschieter, 1991). Furthermore, various by-products of meat industry are lost during the slaughtering process due to unskillful labors, indiscipline in slaughter houses, lack of proper slaughter line, slaughtering on the floor, use of poor quality equipment, inadequate maintenance, high processing cost of by-products, unavailability of equipment for by-product processing and poor enforcement of regulations regarding the discharge of wastes. Approximately 80% people of the developing countries live in rural areas (Kumar, 1989). Animals are usually slaughtered and processed in these arrears either domestically or in the slaughter slabs and no proper facilities are available for by-product processing because it requires a technology and capital lay-out.
Kaasschieter, G.A. (1991). Slachterij projecten in ontwikkelingslanden — ervaringen, aanbevelingen en richtlijnen [development projects for slaughterhouses in developing countries — experiences, recommendations and guidelines]. Directorate General Inter-national Cooperation, The Hague.
Russ, W., & Pittroff, R.M. (2004). Utilizing waste products from the food production and processing industries. Critical Reviews in Food Science and Nutrition, 44, 57–62.
The authors of this article are
- Syed Mudabbar Hussain Shah from Department of Food Engineering. a
- Syed Shabbar Hussain Shah from Department of Soil Science. a
- Mirtab Ali from Department of Food Science & Technology. a
*a = University of Agriculture, Faisalabad.