Food waste can arise at different stages of work. Knowing quantities and causes helps you choose a relevant intervention. The European Commission devotes specific tools and initiatives to the prevention of food waste; the local measure must be consistent with the process actually observed.
I propose to distinguish categories and moments of detection, using a stable criterion. A total data can hide different problems, such as unabsorbed purchases or preparation errors. Registration must be organised without compromising food safety and applicable procedures, which require competent oversight.
In a hypothetical example, one part of the waste arises at the end of the day and another during preparation. The two situations may require different changes. The comparison of quantities allows to focus on the relevant causes, without attributing the whole problem to the initial order.
The subsequent verification uses the same criterion and takes into account the activity carried out. A reduction should be read along with satisfied sales and requests. Measuring the waste is useful when it produces information to prevent the cause and allows you to evaluate the effects of the change without changing method at each comparison.