Bacterial metabolic activity across generations has been shown to be unstable owing to stochastic gene expression and the environments of the bacteria. Previously, the inheritance of bacterial metabolic activity has often been investigated at the microbial community level, and in this study, Wang and colleagues set out to explore metabolic activity inheritance at the single-cell level. They used the lactic acid bacteria Lactiplantibacillus plantarum, which metabolically secretes protons via fermentation, and using an integrated method, they measured the acid-producing activity across different bacterial generations. The authors reported that daughter bacteria of individual ‘superior’ acid-producing cells inherited the strong acid-producing activity from parental bacteria. Moreover, they also found that this increased metabolic activity was retained for less than 30 generations, and later generations (after 30 generations) exhibited decreased acid-producing abilities, eventually regressing to the average level of the parent culture. Finally, the authors reported that this regression was irreversible. Such insights into the inheritance of desired bacterial metabolic traits could be important for the development of biotechnological applications to improve stability and/or predictability of metabolic activity over generations.