FOOD waste REduction through combined microbiological and behavorial STudies – FOODREST

The FoodRest project employed methodologies tailored to each work package (WP).

WP1 focuses on assessing fruit and vegetable (F&V) waste in households. Smart trash cans were distributed to 50 households to mitigate self-reporting biases. Waste data were collected over two one-month periods: in the spring and in the fall, corresponding to the two major seasons of F&L consumption. Concurrently, microbiological swab samples were taken from household storage areas, including refrigerators. The study of microbial diversity combined metagenomic analysis with culture-based methods to isolate and identify the microorganisms responsible for spoilage. Button-type thermo/hygro loggers monitored abiotic factors (temperature/humidity). Finally, fruit and vegetable consumption practices and people’s attitudes toward damaged produce were the subject of an exploratory qualitative study conducted through semi-structured interviews on-site.

WP2 aims to consolidate, at the national level, the results observed in WP1, and to identify a list of the most feasible and effective recommendations for reducing food waste while ensuring public safety. Two quantitative studies were conducted, with the assistance of a panel company, on nationally representative samples (n=1,048 and 815, respectively). Using principal component analysis (PCA), the anti-waste practices adopted by households were broken down into five stages: planning, organizing, reusing, sharing, and refrigerating. A typology of three consumer groups was identified, based in particular on their waste-related practices across these five stages, using hierarchical ascending analysis (HAA) and the dynamic clustering method (K-means).

At the same time, the theoretical efficacy of cleaning/disinfection procedures (sodium hypochlorite, vinegar/baking soda) was evaluated in vitro on contaminated surfaces.

Finally, based on the results obtained and expert opinion (adapted Delphi method), a shortlist of 8 recommendations to be tested was validated.

WP3 focused on selecting the best communication medium for the 8 identified recommendations. A “before-after” experiment with a control group was conducted among households (n=615). The three media used were: posters, Instagram carousels, and videos. Statistical analyses (Tukey’s tests) were conducted to verify whether changes in practices and reductions in waste were greater in the experimental groups. Finally, an algorithmic risk model was developed, based on Monte Carlo simulations, to assess the risk of spoilage and quantify potential savings.

The work in WP1 highlights that a major cause of waste stems from the low perceived residual value (PRV) of damaged fruits and vegetables. This value encompasses symbolic (related to the perceived effort and resources required to grow F&L), hedonic (pleasure and sensory benefits derived from F&L), utilitarian (health benefits or use in recipes), and biospheric (usefulness for compost or animals) dimensions.

Microbiological studies revealed that three-quarters of the spoiled F&L collected had been stored at room temperature, and 75% were collected during the summer. Among the 42 different species of mold identified, Penicillium spp. accounted for more than 50% of the mold isolates. This research suggests that better use of refrigeration for fruits and vegetables could help reduce food waste.

A study of the microbiome associated with storage areas revealed that these areas serve as reservoirs for microorganisms—bacteria or fungi—responsible for spoilage, regardless of the type of storage compartment.

WP2 enabled the quantification of hygiene practices. Those requiring an investment of time or organization, such as washing/peeling before storage or disinfecting the refrigerator, are the least followed.

Consumers recognize five categories of anti-waste practices: planning, organizing, refrigerating, donating, and reusing. Based on the frequency of these practices and reported F&V waste, three consumer profiles were identified. This highlights the importance of tailoring recommendations to each individual.

Furthermore, through an in vitro approach, it has been demonstrated that storage at room temperature is the main factor accelerating the spoilage of fruits and vegetables, and contamination levels in storage compartments contribute to the development of defects. Finally, the biocidal efficacy of common eco-friendly alternatives, such as white vinegar and alcohol, was validated against certain spoilage organisms and pathogenic bacteria.

WP3 focused on the effectiveness of communication materials (posters, Instagram carousel, YouTube video) combined with eight priority recommendations, selected based on the results of WP1 and WP2. Overall effectiveness was observed: the quantities of F&L discarded decreased significantly in the experimental groups compared to the control group. However, no single communication medium performed consistently well across all dimensions of anti-waste practices. Communication materials must therefore be tailored to the target audience and the specific stage of the anti-waste practice being promoted.

In parallel with this experiment, a Monte Carlo simulation-based algorithmic model was developed to assess and quantify the risk of F&V waste, as well as to quantify potential savings based on the adoption of certain practices.

The project opens up three avenues for further work.

The first involves the creation of a “white paper” outlining the actions and practices to adopt to prevent food waste of fresh fruits and vegetables. This document will incorporate all the recommendations evaluated during the project. This white paper will be prepared in coordination with the partners (ADEME and ANSES). The white paper, along with the overall results of the FoodRest project, will be presented during a final event to which project partners, participating households, and the general public will be invited. This event will take place in June 2026.

The second perspective involves a joint scientific article by both project teams, combining a microbiological perspective with a social analysis.

The third perspective is the preparation of the next phase of the FoodRest project, through an ANR call for proposals in 2027.

The ambition of the FOODREST project is to participate in limiting food waste by helping the evolution of conservation practices for fresh fruits and vegetables (F&V) by households.
The objective is twofold: on the one hand, on the microbiological level, it is to identify effective techniques for the conservation of F&V. On the other hand, it is a matter of helping to make households adopt hygiene and conservation recommendations based on some of these techniques. The originality of the project therefore lies in the complementarity of microbiological approaches, in order to better understand the alteration processes according to the places of storage and to explore the effectiveness of hygiene recommendations, and behavioral approaches, in order to understand the perceptions and practices of households in relation to the alteration of F&V.
The purpose of the project is to help health agencies and public authorities to change the behavior of households with regard to the conservation and waste of F&V, by providing recommendations that are both effective and acceptable: effective on a microbiological level as well as in terms of communication, the messages and their mode of dissemination being tested. Acceptable because these recommendations are based on households' actual perceptions and practices regarding the alteration of F&V.