Consumer acceptance of mycelium as protein source

• Effect of growth substrate on disgust is very limited. • Manure for growing mycelium is perceived as natural and disgusting. • Unprocessed mycelium is perceived as natural and disgusting. • Naturalness perceptions in part compensate for disgust feelings. The mycelium of mushroom-forming fungi represents an underappreciated protein source that can be cultivated on agricultural rest-streams and industrially prepared substrates. Consumer food options include unprocessed fresh mycelium or products derived from purified mycelium protein. Both the use of rest streams and the association of fresh mycelia with moulds can create a tension between potentially disgusting and naturalness cues. The current paper investigates this tension in a 3 (substrate: manure, wood, glucose) by 3 (level of processing: unprocessed mycelium cake, purified mycelium protein powder, burger from mycelium protein) experimental survey (N = 449). Results show that substrate source has limited impact on disgust but a slightly greater influence on perceived naturalness. Level of processing has a significant effect on both disgust and naturalness. As expected, social value and attitude based on benefit-risk trade-off inform acceptance. While effects of disgust and naturalness on benefit-risk attitude and social value balance each other, a direct effect of disgust on acceptance remains, underscoring the pivotal role of disgust in shaping consumer acceptance. This suggests for mycelium producers there is freedom of choice of substrate as it has limited effect on consumer acceptance.