Microbiology

Microbiology

Introduction

The Food Microbiology is the branch of microbiology dealing among other aspects of the study of microorganisms that can affect the health quality of food and water. The field of food microbiology is vast and complex, it also includes the general characteristics of these microorganisms, their ecology, environmental resistance, their ability to survive and thrive in food, the consequences of this development and the factors that influencing this process (Pommerville, 2004).

Food microbiology relates to medical microbiology, veterinary, virology, parapsychology, genetics, biochemistry, food technology, and epidemiology. It is important in the design and implementation of the system of hazard analysis and critical control points, critical to ensure food safety, the study of disease outbreaks associated with the consumption of food, in the design and evaluation of modern analysis in the study of the processes taking place during spoilage of food and in the manufacture of those which use microorganisms (Banwart, 1979).

Water Activity in Food Spoilage

Food as a composite system in which water plays a crucial role, if the role of water is well known and more or less well controlled in simple systems, it is far from being well understood and mastered in the development of complex food products. It can serve as a guideline and unifying theme to understand and control the mechanisms responsible for the alteration and extend the life of products.

Water is a basic constituent of food directly affects the quality of the products produced and their conservation. It is directly associated with sensory properties: texture, aroma, flavour. Often the cause of problems observed during storage because it promotes the action of enzymes and micro-organisms, it also plays a vital role in the conduct of processes of conservation and transformation. Interact with other dietary constituents; water plays a role in the conformation, association and functionality of molecules (Adams et.al, 2000).

Water is involved in chemical reactions (as a substrate in the reaction kinetics) and physical processes of evolution Food (mobility factor in the development of the physical structure of the food). The role of water in the sensory properties, especially in the texture of foods can be very different from one matrix to another (frozen products, cell structure, produced little hydrated solid or pasty, compact or honeycomb). Water is also an important player in the perception of flavours.

In products with low humidity can be fat oxidation, non-enzymatic browning, and loss of water-soluble substances (vitamins), the damage caused by enzymes. Microbial activity is suppressed. In products with intermediate humidity can occur under different processes, including those involving microorganisms? The processes taking place in high humidity, microorganisms play a crucial role.

Water activity (aw) in food

Product

Humidity%

aw

Fruit

90-95

0.97

Eggs

70-80

0.97

Meat

60-70

0.97

Cheese

40

0,92-0,96

Jam

30-35

0,82-0,94

Bread

40-50

0.95

Cake

20-28

0.83

Flour

16-19

0.80

Honey

10-15

0.75

Caramel

7.8

0.65

Cookies

9.6

0.60

Chocolate

5.7

0.40

Sugar

0-0,15

0.10

pH in Food Spoilage

The pH control is very important in the preparation of foodstuffs, such as indicator as to the hygienic control of the transformation ...