A social experiment was conducted in collaboration with the Regional Council of Vallès Oriental (Barcelona) to investigate the consumer understanding and acceptance of different valorisation methods for food surplus and side-flows. Of particular interest was the extent to which consumers accept and even appreciate products resulting from the following innovative waste valorisation processes:

• gleaning vegetables and converting them into foods such as soups or creams;
• extracting ingredients (vitamins) from product surpluses and using them for food enrichment;
• converting food-processing by-products to feed and feed supplements for animals intended for human consumption;
• converting catering food surpluses to liquid feeds for pigs intended for human consumption (currently banned in the EU).

Parents of school children were asked to determine whether they would be open to the Council favouring catering companies that integrate valorised foods from food surpluses or side-flows when hiring school catering services. They heard evidence from experts about the different food valorisation methods, discussed this and decided the valorised foods to be considered for school caterings’ menus in a hypothetical discrete choice experiment.

This work identified the relevant factors that influence the acceptance or rejection by consumers. These factors include familiarity, knowledge, perceived risks, perceived benefits, experiences on food processes, involvement, trust between consumers and producers, information, naturalness, local origin, levels of processing, trust in food regulatory institutions, sustainability, safety, complexity, moral considerations, traceability, and transparency.

We find that informational strategies can contribute to the acceptance of valorised products by consumers. The provision of information has a larger likelihood for success, if it is continued until these kinds of food become familiar to the public. The outcomes of the experiments suggest that the acceptance of the studied valorisation methods is complex and needs time because it requires removing any existing negative perceptions towards such methods.

The findings suggest that a focus on framing the message in a positive way, pointing out the potential benefits for the consumer (such as taste, naturalness, local origin, environmental friendliness, animal welfare, social inclusion, etc.), creates more positive motivations towards acceptance.

A remarkable result from the study is that although gleaning-based valorised products were deemed acceptable to be used within the setting of school lunches, the other valorisation methods were not, however, the participants did not view them as unsuitable for adult consumption. In contrast to their stated perception of valorised products as safe for health, presented with the option of giving these products to their children it evoked a negative response, ‘just in case’... . To increase the confidence in the safe use of valorised food products, it can therefore be recommended to first focus on adult consumption on the short term.

It is recommended that potential legal barriers for studied valorisation methods, including gleaning, ingredients enrichment, by-products used as animal feed, and catering food surpluses as animal feed (ecofeeds), are investigated and where necessary addressed / explained with further guidelines. The potential for upscaling should be supported through financial and organisational support from various stakeholders.