Our bodies are familiar with acid, from fruit and good bacteria (for example, the lactic acid bacteria in yoghurt). When the acid is not too strong and comes in combination with other nutrients, it gains the trust of our taste buds. Thus we like to include an acid component when we cook a pleasant-tasting meal — tomatoes in the sauce, a squeeze of lemon over the fish, a glug of wine over the frying onions. This well-placed pleasure is fascinating for anyone with an interest in microbes.
