Comparing Lab-Measured and Surveyed Bread Waste Data: A Possible Hybrid Approach to Correct the Underestimation of Household Food Waste Self-Assessment Surveys

Abstract

Among the common methods of quantifying household food waste, direct measurement is regarded as infeasible due to its prohibitive costs, and self-assessment methods tend to underestimate the actual values. This paper aims to propose a methodological approach to reach a compromise between feasibility and accuracy. Bread was studied, since it is a relatable example. The self-assessment method was used to survey 419 households in Shiraz, Iran, during 2019 to estimate household bread waste (BW) and to identify waste-causing consumption recipes (WCCR). These WCCRs were replicated in the lab, and the resulting BW was measured. The underestimation in the self-assessment method was revealed by comparing the survey results with the lab measurements. The underestimation ratio (UR) ranged between 1.24 and 1.80. The pattern of difference between these four bread types was similar among the survey and lab data. In conclusion, the lab measurements may estimate BW caused by the WCCRs more accurately. This suggests that URs can be applied to correct the underestimation in self-assessment surveys. Such an approach could provide the basis for further research on the development of cost-effective methods to quantify waste across a variety of food commodities.