不同规模餐馆食物浪费及其氮足迹——以北京市为例

The nitrogen footprint of different scales of restaurant food waste: a Beijing case study

餐饮食物浪费的普遍性和严重性已得到了社会各界的关注。通过实证研究的方法对餐饮消费中食物浪费问题进行了研究,并从食物全供应链的视角,对比分析了不同规模餐馆食物浪费的氮足迹及其环境影响。研究表明:北京市餐饮食物浪费人均浪费量为74.39g/人次,其含氮量为1.24g/人次,约占总浪费量的2%。北京市餐饮食物浪费所引起总的氮排放量为16.37 g/人次,其中有1.24g/人次的氮排放来自于食物的直接浪费,其余15.13g/人次氮排放来自于食物生产过程。北京市餐饮食物浪费的氮足迹为0.22g N/g,即每浪费1g的食物,就会有0.22 g的氮排放到环境中。对比不同规模餐馆的食物浪费情况可知,大型餐馆的人均浪费量最高,有99.38g/人次,其氮排放量也相应最大,为22.53g/人次;中型餐馆和小型餐馆的食物浪费人均量及N排放量依次减少,而快餐的最低,仅为北京市整体平均水平的1/3。

Recently, research on food loss and waste and the related environmental impact has increased globally. Wasted food creates nitrogen emissions throughout the food supply chain, from agricultural production and food processing to consumption and waste disposal. Although the generation of food waste must be reduced, the lack of quantitative information on the production of household and catering food waste has led to an underestimation of waste volumes and inhibited the development of sufficient policy interventions designed to decrease food waste. The present study investigated the volume of catering food waste generated in Beijing and calculated its nitrogen footprint. In the present study, we focused on avoidable food waste, i.e., all wasted food and raw materials that could have been consumed had they been prepared differently. Other bio-wastes, such as vegetable peels, bean dregs, or bones, were not measured. During first-hand surveys of the catering sector of urban Beijing in 2013, 136 restaurants were studied. These establishments were divided into large, medium, small, canteen, and fast-food restaurant categories. A total of 2,704 samples were collected, each consisting of two parts：a consumer questionnaire and the weight of the sample of food waste generated by consumers of the establishment. Then, the nitrogen footprint and its discharge to the environment were calculated. The main conclusions of the present study are：（i） an estimated 74.39 g of food waste is produced per non-household meal in urban Beijing. Food waste generation differed significantly among restaurant types. For example, large restaurants generated the most waste-99.34 g, three times that produced by fast food restaurants （30.27 g）. （ii） The food waste comprised many different food types, the most prominent （by weight） being vegetables （44.18%）, followed by aquatic products （12.04%）, pork （8.60%）, beans and bean products （7.69%）, poultry （7.50%）,wheat flour （6.96%）, rice （5.36%）, beef （1.90%）,mutton （1.89%）, other meat （1.22%）, eggs （1.20%）, nuts （0.97%）, other grains （0.24%）, fruits （0.20%）, and dairy products （less than 0.1%）. （iii） The total N discharge to the environment was 16.37 per non-household meal, and the nitrogen footprint of the catering food waste produced per non-household meal in Beijing was 0.22 g N/g. By food category, the largest proportion of the calculated nitrogen emissions was generated by meat （30.65%）, beans and bean products （26.61%）, and grains （12.90%）. By process, the food production stages producing the largest proportions of the emissions were agricultural production （almost 85%）, waste management （7.60%）, and fertilizer production （37.39%）. Nitrogen discharge to the atmosphere, soil, and water was 7.34, 1.34, and 7.69 g per non-household meal, respectively. （iv） For the waste volumes, large restaurants generated the most N discharge-22.53 g three times that produced by fast food restaurants （5.67 g）, followed by the medium （18.05 g） and small （13.05 g） restaurants.