The extensive and some times over use of cleaners and sanitizers can sometimes cause them to be found in the milk.

Previously, only chlorine sanitizers were used and seldom did they do any harm to production, as they were inactivated in the milk during storage.

The milk has to contain high concentrations of chlorine sanitizers before noticeable changes in the milk, and before acid production ability is affected. The appearance of different types of disinfection agents has on the other hand been much more annoying for cheese production, by being more harmful to acid development.

The Danish Government Dairy Research Plant reports that when investigating 4 different types of quaternary ammonium compounds, addition of only 0.0002 - 0.005% of these to milk has shown a reduction in acid production (aroma-bacteria are even more sensitive - E. Skovmose/Voss Trials).

Rapid detection of these compounds in the milk must be in place. Chlorine sanitizers are easily detected with the help of the Wodes test and the same is the case with hydrogen peroxide, but today fairly simple methods to determine quarts in milk are also available.

Antibiotic

Antibiotics can easily be determined in milk. Testing equipment under brand names of Charm, Penzym and others are today used for testing milk to ensure that milk is free of any antibiotics before cheese making.

Bacteriophage

Plants must gear themselves to a higher standard of hygienic conditions, if they wish to avoid bacteriophage infection.

The whey should, under all circumstances, be pasteurized to kill lactic acid, bacteria (the bacteriophage' hosts).

Whey and cheese milk should not be treated in the same HTST heat treatment system. (But, if necessary, always finish all milk before running whey.)

If the whey tank is in the basement, and the whey is drained directly into it, air must not be allowed to escape into the cheese room. Whey spills on the floor, etc., should be avoided and the floor should be rinsed with chlorine sanitizer several times a day and disinfected carefully after work has been completed. Grouting should be carefully maintained. Waste water spraying and other treatment of waste water should be done as far from the cheese plant as possible.

Personal hygiene should be accommodated by having easy access to disinfectant and sanitizers, e.g. iodophore and chlorine sanitizers.

Hands and arms should always be sanitized before handling any food and room temperature should be at a comfortable level to avoid sweating, which could contaminate products. This all promotes better work.

Bulk cheese starter should be propagated in a special room where utmost consideration is taken to avoid infection. The cheese make room is the wrong room in which to place the culture tank.

GOOD COAGULATION ABILITY

Cheese milk can have different coagulation abilities and this can be caused mainly by different particle sizes of casein.

The higher the content of Ca++, the bigger the casein particles will be. The bigger the particles are, the better the coagulation ability, as Ca++ form the network, which holds it all together to a solid mass, which we cut with knives.

Particle size also influences the ease by which cheese curd shrinks and releases whey. If they are big, the network is open and coarse, and whey drains more readily.

Different factors influence the content of calcium and phosphate, especially in late lactation milk and milk from diseased animals. Because these minerals are essential to form the network, any abnormality will affect coagulation of the milk. Therefore, avoid such milk where possible in Cheesemaking.

If the milk is stored at low temperatures part of the beta-casein and calcium ions we released from the casein particles, which can explain reduced rennet ability. The reduction is greatest for milk which has been pasteurized prior to being stored.

To compensate for precipitation of calcium, calcium chloride can be added to the milk (up to 20 grams per 100 liters).

If the salt (NaCl) content in the milk is too high, ion exchange occurs, so that the calcium is displaced from casein by sodium, which to some extent decreases the milks' coagulation ability.