Preserving Food and Drink

Micro-organisms has many useful functions in the food industry. Some examples are yogurt fermentation by lactobacillus culture, yeast leaven in bread making and alcohol production by yeast beer and wine. But also microorganisms responsible for spoilage of food and some are pathogenic micro-organisms.In fact food spoilage caused by enzymes produced from micro-organisms, and remove from the enzyme most easily achieved by eliminating the micro-organism itself. For the growth and propagation, micro-organisms require organic food (protein, carbohydrate, fat), a suitable temperature, some moisture, in many cases fresh air and pH appropriate. Knowledge of the necessary conditions for growth, will also provide insight on how to prevent micro-organisms grow and therefore prevent food spoilage.However, any other measures taken regarding the preservation, it is obviously important that the food is processed under the highest hygienic conditions in order to minimize microbial load and minimize the possibility of contamination.Bottlenecks in the production process (temperature)

Increasing the temperature causes an increase in the activity of micro-organisms and enzymes. As a rule of thumb, for every increase in temperature of 10 ° C, the activity increased twice. This rule is true in the temperature range of 0 to 60 ° C. At temperatures above 60 ° C, micro-organisms and enzymes are destroyed or inactive. Depending on the combination of temperature / time applied (pasteurization, UHT sterilization, HTST), part or all of the micro-organisms have been destroyed and the enzyme is inactive. However, it is important to note that the heat-resistant species and spores can survive heat treatment.This drop in temperature also reduces the activity of micro-organisms and enzymes. In the refrigerator (4 to 6 ° C) and in the freezer (-15 to - 20 ° C), micro-organisms are less active or not active at all, but they are not destroyed.Barriers in packaging (air / oxygen)

By carefully selecting packaging materials and packaging processes (vacuum packaging or modified atmosphere packaging), oxygen as growth factors can be eliminated. It should be noted that there are anaerobic micro-organisms that live without oxygen, and among these are some food pathogens.Obstacles in the composition of foods (pH, Aw, acidulants and preservatives)

As stated above, the highest quality ingredients, with the lowest possible number of microbes, should be used. Furthermore, the composition of the food itself creates an environment that is more or less attractive to micro-organisms and make food more or less susceptible to spoilage of food.Two very important factor is the presence of water and acidity of food.Water is essential for micro-organisms and therefore drying is an effective method for preservation preservation methods, such as the addition of high salt levels and the addition of a high sugar content, based on the reduction of water available for micro-organisms. Water availability can be characterized by the so-called water activity (Aw).Preservation, by affecting the level of acidity (pH), carried out through the addition of an organic acid, such as pickles in vinegar. Chemical preservatives may be added to reduce or inhibit the activity of micro-organisms.The approach incorporates multiple barriers, namely food processing, food packaging and food composition is the most effective and will result in a lower dose of preservatives needed.