The most efficient way to ensure that producers are responsible for product is through

the answer is: Labelling

Labelling is used by companies to show several crucial information that related to their products. Those information could include things such as ingredients,  nutritional value, how to contact the company's customer service, etc). All of these information are needed to ensure that customers could held the producers accountable for the products they created.

answer; test-retest;

answer///ability to capture the attention of users;