Fermented sausages

Traditionally produced by chance contamination with local microorganisms; modern practice adds starter cultures to the sausage emulsion for a uniform product. Lactic starters are common, plus nitrate-reducing organisms that shape colour. Fermentation affects colour, consistency and flavour, and the resulting acidity is a key safety hurdle against pathogens. Typical products — salami, pepperoni, chorizo — ferment at 20–25°C until pH falls below about 5.3, then dry to water activities under 0.90. This combined acid-plus-drying hurdle controls Salmonella, E. coli O157 and Listeria; starter cultures of Lactobacillus sakei and Staphylococcus xylosus are selected for acid, colour and flavour performance.