Fermentation, Food Safety Glossary

A preservation method that uses beneficial microbes to produce acid or alcohol, lowering pH and controlling harmful bacteria in foods such as yoghurt and sauerkraut. Fermentation is a food process in which beneficial micro-organisms, such as lactic acid bacteria or yeasts, convert sugars in the food into acids, alcohol or gases. This is how foods such as yoghurt, cheese, sauerkraut, kimchi, salami and sourdough are made. As well as creating distinctive flavours and textures, fermentation preserves food, because the acid or alcohol produced makes conditions hostile to many spoilage and disease-causing bacteria. The main safety mechanism in most fermented foods is a drop in pH as acid is produced, which controls the growth of harmful bacteria. For fermentation to preserve food safely, the right microbes must dominate and the pH must fall quickly and far enough, so it is a controlled process rather than simply leaving food out. Poorly controlled fermentation can allow pathogens or, in low-acid conditions, Clostridium botulinum, to grow, so recipes, time and temperature matter. For an Australian producer, safe fermentation means using a reliable method, often a starter culture or an established recipe, controlling salt, time and temperature, and checking that the pH drops as expected. For fermented meats such as salami, this is a critical control, and producers commonly measure pH and water activity and keep records to show the process worked. Businesses fermenting foods should understand whether the finished product is shelf-stable or still needs refrigeration, and label it correctly. Vegetable ferments such as sauerkraut and kimchi rely on enough salt and full submersion under brine to encourage the right bacteria, while dairy ferments rely on cultures and temperature control. Where fermentation is a key food safety step, it should be built into the food safety program. A producer making fermented salami inoculates the mince with a starter culture, controls the fermentation room temperature and humidity, and measures the pH over several days to confirm it falls into the target acidic range. The batch pH and water activity readings are recorded, giving evidence that the process controlled harmful bacteria before the salami is dried.