Cheese rinds are not accidental. They're microbial ecosystems that self-assemble in reproducible succession: bacteria colonize first, followed by yeasts, then filamentous fungi. The temporal sequence is consistent across different cheeses, different dairies, and different countries — suggesting the succession is governed by ecological principles rather than local contamination.
Research on cheese rind microbiomes (Cell, 2014; Nature Communications, 2023) shows that flavor development during aging is driven by interactions between microbial species, not by individual organisms acting independently. The kokumi flavor profile of aged cheese — the full-bodied, lingering quality that distinguishes a 24-month Comté from a 3-month one — emerges from peptides produced by the combined metabolic activity of the community, not from any single species' contribution.
The counterintuitive finding: less is known about interactions involving more than two starter cultures than about pairwise interactions. Cheese science has characterized hundreds of two-species interactions (does species A help or hinder species B?) but struggles with the combinatorial explosion of three-way, four-way, and higher-order interactions that determine the actual flavor of complex aged cheeses.
This is a general problem in microbiome science. Pairwise interactions are tractable — grow two species together, measure the outcome. But community behavior emerges from the network of interactions, not from summing pairwise effects. A species that cooperates with A and competes with B may do something entirely different when A and B are both present.
Cheese rinds are useful precisely because they're simple enough to study but complex enough to exhibit emergent behavior. The rind is a model system for microbial ecology — the Drosophila of community dynamics.