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Measuring pH in shampoo

Published 18. December 2015

Shampoo is a hair care product used for removal of dirt, dandruff, skin particles, oils and other contaminated particles.

As the scientists behind hair care progressed, manufacturers synthesized chemical additives for use in shampoo as fragrance, foaming agents, and colored dyes. Shampoo is now created and structured towards various hair types, as well as to achieve a certain end result, such as the reduction of dandruff or greasy hair. Both the synthetic and natural ingredients used in a shampoo dictate the pH of that particular product. The pH of a shampoo will alter the natural pH of skin and hair, which ideally falls between pH 3 and 5 and pH 4 and 5, respectively, thereby affecting their physical and chemical makeup.


Food and Dairy



HANNA Instruments offers a wide range of products and chemical test kits for measuring different parameters, which are very important for all the food industry and for the whole production, which is divided into four stages:


  1. Purchasing and stocking of raw material
  2. Production
  3. Keeping and stocking
  4. Transportation, distribution and retailing


In each of the above mentioned stages there are critical points at which specific checks would have to be carried out in order to ensure the planned qualitative level.

All parts of the food industry can benefit from our instruments. Several important parameters can be tested, for instance pH, temperature, salinity and the sodium content, conductivity, content of sugar, etc.


The importance of various parameters in the food industry


In the following paragraphs there are listed the reasons of various parameters in the food industry.


  1. Which are the parameters to be controlled in the different phases within the food indusrty?


    1. Purchasing and stocking of the raw material


Once we have obtained the raw material, specific checks on hygiene and quality have to be carried out since the quality of raw materials influences extensively on the quality of the final product.




In order for the milk to be fresh and of good quality it is important to control the pH. The acidity has to be very low (pH = 6.4 – 6.8). In cases of higher acidity it could mean bad treatment or also the presence of microorganisms. Furthermore, if acid milk does not come already coagulated, there is a possibilty that it may coagulate while being pasteurized and then it can damage the devices.


It is also very important to check the presence of sodium. In cases of high values of sodium, it could mean that animals have a very frequent illness-mastitis, which causes the milk not suitable for people. The normal value of sodium should be 18 – 20 mEQ/L.




In this phase it is very important to control three significant parameter: pH, temperature and humidity.

In order to prevent bacterial contamination it is important to follow hygienic rules during the slaughtering, keep the meat at constant temperature and avoid too much time between the slaughter and consumption (at the most 15 days).


The value of pH between 5.3 and 5.5 indicates a correct course of hanging. 


After the slaughtering the meat should be kept at the temperature around 10 - 15°C for at least 12 hours to avoid meat hardness. Later the meat is to be kept for several days at a temperature of refrigeration (+4°C) to avoid germs multiplying.


Flour from cereals


The main problem is mould. The mould is dangerous because it may cause the development of mycotoxins.

In order to avoid this it is important to check two parameters: temperature and humidity.


Vegetables and fruits


In this field there are several important factors: pH, temperature, humidity, but also soluble solids, acidity and sugars. The sugar parameter is very important to determine the ideal moment for harvesting. The sugar parameter can be measured in an easy and fast manner by using the refractometer.




The fish is similar to meat, however, it deteriorates easily, therefore besides controlling pH, it is important to monitor also the temperature during the stocking and the transportation.


Olives and seeds


Usually the time between harvesting and pressing the olives is rather short, but it can also delay a bit if we keep the olives in dry and airy places. In this case it is important to monitor temperature and humidity.


                 B. Production




The meat goes through various preparations in order to keep it well.


One of the principal typologies of meat preparation are salamis. Their seasoning takes place in appropriate places where the preparing remains from 1 to 5 months at the temperature from 11 - 15°C with the relative humidity of 85%.


In this phase there is a decrease of the water activity and simultaneously also and increase of the concentration from 2.5 – 3.5 % to 10%. Firstly the pH reduces but then it rises up to 5.3 to 6 pH.

The important parameters to be tested are: temperature, relative humidity, water content and pH.


Dairy products


Pasteurized milk

In this process it is very important to monitor carefully the temperature in order to decrease the bacteria of the milk and to make it more resistent for a longer period.




The parameters which have to be controlled are the temperature and the pH.


In order to obtain the yoghurt, firstly we have to standardize (6.5 – 6.7 pH) the raw milk, then we have to pasteurize it (90°C for 5 minutes), homogenize it and concentrate it. After that we can proceed with the inoculation of bacterial cultures of lactobacillus and streptococcus in balanced percentages. During the incubation it is important to preserve the temperature from 42 - 43°C for 3 hours. This phase will reach it balance, when pH gets the value of 4,2 – 4,3. The final product can be kept for 40 days at the temperature of 4°C.




In the production of cheese it is important to monitor the following parameters: Temperature, pH, salinity and humidity.


The cheese production starts with the pasteurization of the milk, which is carried out at 70°C for 10 – 15 seconds. What follows is the addition of lactic bacteria and coagulation. This happens due to the acidity of milk from the bacteria or due to the addition of rennet (like this milk reaches the temperature from 30 - 37°C). In both cases the pH of milk is decreased to 4,6 and then occurs the precipitation of the casein fraction of milk proteins.

Unlike the raw cheeses, the curd is heated to the temperature between 38 and 60°C for 15 minutes to half an hour, so that the curd is separated from the serum. When this phase ends, the curd is sipped from the serum and put into pots, where pressing follows.

Then salt is added with rubbing the salt grains directly on the surface or they are put into brines at 18 – 24 % NaCl.


In the end, after the salt, the phase of hanging starts, which in the case of cheeses can last from few days to more than one year. This process is carried out at checked temperature and humidity. 


          C. Conserving and stocking


Perishable products like for instance pasteurized milk and fresh cheeses do not go through this phase, because the time from the production to the consuming is rather short.


Other products like for example pasta, flour and meat are stocked before the actual selling. In this case it is important to check the temperature of the stocking, humidity and with oil also the light. 


           D. Transport, distribution and retail


Also during the transportation it is necessary to keep the same stocking conditions.

For perishable food, which requires low temperature, it is important to conserve the cold chain. During the transportation, especially with long distances, it is necessary to control the humidity, since the seeds can start to sprout or the flour can become mould.


       2. Why is it important to measure the content of sodium in groceries?


Sodium is a natural component of many groceries. It is added also to other groceries in the form of salt. The content of sodium in groceries can have significant influences on health.





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