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The commercial sterility standard for low-acid canned food: a heat process delivering twelve decimal reductions of Clostridium botulinum spores.
This is why canned foods like tinned vegetables, meats and soups sit safely on a supermarket shelf for years without refrigeration.
See also: D-value, F-value, Commercial sterility, Clostridium botulinum
An anaerobic, spore-forming bacterium producing botulinum neurotoxin. Proteolytic types do not grow below pH 4.6, aw 0.94 or 10 °C.
The reason home-canned low-acid vegetables need a pressure canner, not just boiling water, and why a bulging or dented can is never opened.
See also: 12D concept, Low-acid food, Water activity
The condition in which no microorganisms capable of growing under normal storage conditions remain, though highly heat-resistant spores may survive.
What lets a tin of beans sit in a warehouse for two years at room temperature without spoiling, even though it isn't completely free of microorganisms.
See also: 12D concept, Sterilisation
The time at a given temperature required to destroy 90% of a microbial population — one log reduction.
Used by canneries and sterilisation engineers to work out exactly how long a product must be heated to kill enough bacteria to be safe.
See also: z-value, F-value, 12D concept
The total lethality of a heat process expressed as equivalent minutes at a reference temperature. F0 is the reference at 121.1 °C with z = 10 °C.
Used by food engineers to design a canning (retort) process that guarantees a can is actually safe, not just cooked through.
See also: D-value, z-value, 12D concept
The controlled use of microorganisms or their enzymes to convert food substrates, producing acids, alcohol, gas and flavour compounds.
What turns milk into curd and dosa batter into a light, sour, bubbly mix overnight.
See also: Lactic acid bacteria, Probiotic
Gram-positive, non-sporing bacteria producing lactic acid as the main fermentation product — Lactobacillus, Lactococcus, Streptococcus, Leuconostoc, Pediococcus.
The organisms behind curd, yoghurt, dosa batter and pickles, and the reason probiotic drinks list specific bacterial strains on the label.
See also: Fermentation, Probiotic
The temperature increase required to reduce the D-value by a factor of ten — the slope of the thermal death time curve.
Used alongside D-value by canning engineers to predict how a sterilisation process needs to change if the processing temperature is adjusted.
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