Comparative life cycle assessment of plasma-based and traditional decontamination strategies on Norwegian ready-to-eat fresh spinach

Purpose The goal of this study was to determine the environmental life cycle impacts of fresh spinach and potential benefits reducing food waste using three proposed treatment methods. The investigated processing methods included rinsing with either tap water (reference scenario), or the novel food processing technology Plasma Activated Water (PAW scenario), as compared to not rinsed products (untreated scenario). The study applied comprehensive life cycle inventory for the entire fresh spinach value chain. Methods The life cycle assessment follows the ISO14044 guidelines. The following impact categories were included: global warming potential, ozone layer depletion, acidification, eutrophication, abiotic depletion potential, abiotic depletion fossil and water use. The reference flow of fresh spinach was calculated by means of material flow analysis. The functional unit was set up as 1 kg fresh spinach consumed raw by end-users. A “cradle to grave” approach was implemented, with Norway as target geographical area. Consumer related impacts (except wastage) were not considered in this study. Activity data (e.g. food waste, processing technology life cycle inventories, transport distance, etc.) were case specific whereas process data (e.g. lorry inventories, energy production, waste treatment, etc.) were derived from the Ecoinvent 3.5 database. Results and discussion According to current industrial practices, production of 1.35 kg spinach is required per 1 kg eaten by consumer. The food waste impact according to current practices accounts for 18-22% within the assessed environmental burdens. The PAW and untreated scenarios were assumed to reduce, respectively, 50 and 25% food waste through shelf-life extension. For the PAW and untreated scenarios, the avoided environmental burdens ranged 6-8% and 5-6% respectively. Although it is uncertain whether prolonged shelf-life can reduce food waste, the potential of labelling strategies such as “best before” and “close to expiry date” has been demonstrated in this regard. Conclusions Both untreated and PAW scenarios led towards decreased environmental burdens and annual costs by food waste reduction compared to the reference scenario. PAW rinsing showed the greatest cut potential both environmentally and economically. For PAW, the most significant decreased impact category was eutrophication potential. Further research is needed to establish a direct connection between shelf-life extension and food waste reduction throughout the spinach value chain.