Oh No my starter is not working!!

Starter failure is the thing that can keep cheese makers awake at night. This issue we will discuss ways of minimising the risk of stater failure.
Starter inhibition
Starters can be inhibited, or their effectiveness reduced by the following:
Bacteriophage (Phage)
 Phage are virus’s that attacks bacteria, they can cause the death of starter bacteria resulting in “dead” vats where there is no acid production. Viruses are not living organisms but contain a nucleus which is injected into a living cell. This then reproduces in the cell until the cell bursts, releasing up to another 20 virus particles. Virus’s thus multiply much quicker than the starter bacteria and can quickly kill all the starter bacteria.
 This will result in the cheese being low acid and a potential health risk.
 Phage can build up in the environment. To prevent phage attacks consider the following:
o Clean up the curd of the floor and equipment regularly.
o Don’t leave it until the end of the day.
o Don’t leave pools of whey on the floor.
o Have a regular floor, wall, ceiling and drain sanitation procedure.
Rotate cultures, use different strains regularly . Phages are specific to a starter strain. E.g. when making cheddar cheese lactococcus lactis ssp cremoris is the bacteria used. However there are numerous strains, or variants of this culture that are offered for sale by starer culture companies. Each strain may produce acid at a slightly different rate. Starters strains are combined so that phage unrelated groups are used together therefore if 1 strain is attacked by phage the other strains in the mix can still produce enough acid to enable cheese to be made. Mesophile cultures are generally more susceptible to starter attack than thermophiles. Most freeze dried cultures are a Mixed strain to make them more resistant to phage attack. `
 Bacteriophage cannot survive unless they are present on a host and are destroyed by pasteurisation, freezing and chemical and heat sanitation
Other Causes of Inhibition
 Lactoperoxidase system. Lactoperoxidase is a naturally occurring enzyme. If present in large amounts in milk this will cause starter inhibition.
 Excessive agitation during bulk starter manufacture incorporating air, making froth, will cause less starter growth
 Antibiotics. Antibiotics in milk will attack the starter culture resulting in poor starter growth.
 Sanitisers, If the sanitiser is not all drained out of the vat then this can inhibit cultures

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