Carbon Footprint and nutritional aspects of an upcycled food product based on slaughterhouse blood

In today’s world, it is crucial to ensure sustainable food production and consumption while maintaining food security. Food waste from industrial production is a major problem that affects both food security and the achievement of a circular economy. While preventing food waste is the most preferable option, when it is not achievable, valorization through upcycling, can offer a more beneficial alternative compared to conventional recycling methods. Slaughterhouse blood is one of the primary contributors to the total volume of edible by-products generated in the Swedish meat industry. However, this blood has great potential beyond its current use in biogas production as it is a rich nutrient source and has many functional properties. This study was conducted in collaboration with the Axfoundation, where a bakery product called Black brownies was developed using rescued cattle blood as part of a food waste reduction initiative. The aim of the study was to calculate the carbon footprint of the new food product, evaluate the influence of different allocation methods on this cabon footprint value, identify its climate hotspots and assess its nutritional composition. The carbon footprint was calculated using two different allocation methods for the burden of blood: as the full value of beef or as missed out biogas production, respectively. The scope of the study was from “cradle to bakery gate”. The carbon footprint values were 7.5 and 1.5 kg CO₂e per kg brownie respectively, for the first and second allocation method. Conventional chocolate cake was used as the reference product and had a carbon footprint of 1.7 kg CO2e per kg cake, but was calculated based on a recipe without dark chocolate. The production of the ingredients was the most significant hotspot in this new product. The carbon footprint was subject to several limitations, including assumptions made for the allocation of blood and data gaps regarding production conditions (baking of kladdkaka was used as a proxy). One main nutritional difference was the significantly higher heme iron content in the blood-enriched brownie when compared to a regular chocolate cake, offering a novel way to introduce iron through a familiar sweet food like Swedish fika, for those who are not willing to eat blood based savory food.