Course work on the theory of food production pasteurized milk

Contents

INTRODUCTION

1 LITERARY REVIEW

1.1 Primary processing, transportation and storage of milk

1.1.1 Primary processing and transportation of milk

1.1.2 Acceptance and evaluation of milk quality

1.1.3 Milk Purification Methods

1.1.4 Milk cooling modes

1.2 Milk machining

1.2.1 Separation and normalization of milk

1.2.2 Homogenization of milk

1.3 Heat treatment of milk

1.3.1 Effect of heat treatment on milk properties

1.3.2 Pasteurization of milk

2 PROCESS PART

2.1 Milk processing technology

2.2 Food calculation for drinking milk from m. D.J.3.2%

3 PROCESS EQUIPMENT

3.1.1 Selection of process equipment

3.1.2 Equipment

3.1.3 Single-circuit cooler for milk OP-1000M

3.1.4 Capacity for acceptance and reservation of PM-B-milk

3.1.5 Milk cooling pasteurization unit (pasteurizer) PMR-0.2 W

3.1.6 SELS-1,5M self-unloading separator-dryer

3.1.7 Centrifugal electric pump G2-OPA

CONCLUSION

LIST OF LITERATURE USED

Introduction

Milk is a food product that is most perfect in composition. The value of milk lies in the ideal balance of nutrients. Dairy products play a huge role in human nutrition, providing the body with elements necessary for health. Milk is the least replaceable product, especially for baby food. The milk of various farm animals differs in chemical composition and nutritional value. The most widely used in the nutrition of people is cow's milk. In the diet of peoples of various regions there is also milk of goats, sheep, mare, camel, donkey, buffalo, female zebu, yak, reindeer.

Milk is a complex product in its chemical composition. Milk includes: water, proteins, milk fat, milk sugar - lactose, minerals and trace elements - calcium and phosphorus, most known vitamins, enzymes that promote digestion; hormones, immune bodies, gases, microorganisms, pigments.

Milk - raw materials for the production of fermented milk products and drinks, cheese, butter, cream, ice cream.

The dairy industry produces pasteurized cow's milk, sterilized, melted, condensed, dry.

1 literary review

1.1 Primary processing, transportation and storage of milk

1.1.1 Primary Milk Treatment

High quality dairy products can be produced only from benign raw milk. Benign milk is characterized by a normal chemical composition, optimal physicochemical and microbiological indicators that determine its suitability for processing. The change in the properties and, especially, microbiological indicators of raw milk is largely due to the vital activity of microorganisms that enter the milk in case of non-compliance with sanitary and hygienic rules for milking, keeping animals, washing equipment for milking, storing and transporting milk. To prevent bacterial contamination of raw materials, it is necessary not only to comply with sanitary and veterinary rules for the production of milk, but also to undergo primary treatment. The purpose of the primary treatment is to ensure the resistance of milk during its transportation and storage.

Primary processing includes the following processes: cleaning, cooling and storage before sending for processing or implementation.

To remove mechanical impurities, milk is filtered by passing through the fabric, and then sent for further purification. Filters of different systems are used for cleaning, where cotton disks, gauze, synthetic materials, metal nets, etc. serve as working elements. Currently, separator-and-oil cleaners are used to purify milk, in which mechanical impurities are removed under the influence of centrifugal force. After purification, the milk should be cooled immediately to suppress the growth of microorganisms, plate coolers are used to cool the milk.

Cooled (not higher than 6 ° C) milk is transported to large dairy enterprises in metal flasks, tanks by road, rail and water transport. Flasks for milk with a capacity of 36... 40 l are made of aluminum and steel. When transporting large quantities of milk, tankers made of stainless steel and aluminum are used. They have insulation and are equipped with hermetically closing hatches.

1.1.3 Milk Purification Methods

Purification is carried out in order to remove mechanical contaminants and microorganisms. Cleaning is carried out by filtration method under action of gravity or pressure forces and by centrifugal method on separator-cold purifiers. When filtering, milk must overcome the resistance exerted by a filter partition made of metal or fabric. When the liquid passes through the filter partition, contaminants in an amount proportional to the volume of the liquid passed through the filter are retained on it.

Periodically every 15... 20 min it is necessary to remove contaminants from the filter. The efficiency of the purification depends to a large extent on the pressure at which the filtration takes place. Typically, the cylindrical filtration apparatus receives milk at a pressure of 0.2 MPa. Filtration devices with fabric partitions have a number of drawbacks: short-term non-stop operation; the need for frequent disassembly for washing; possibility of tissue breakout; reduction

performance of filters depending on duration of operation.

The most effective cleaning of milk with the help of separator milk cleaners. Centrifugal cleaning in them is carried out due to the difference between densities of milk plasma particles and foreign impurities. Foreign impurities, whose density is greater than that of milk plasma, are thrown to the drum wall and settled on it in the form of mucus. Milk to be cleaned is supplied via central tube (Fig.1, a) to tray holder, from which it is directed to slurry space between edges of tray pack and cover. The milk is then fed into the intertidal spaces and along the gap between the tray holder and the upper edges of the trays rises up and exits through the holes in the drum cover.

The cleaning process begins in the slurry space, and ends in the interstage spaces.

Traditionally, in process lines, the centrifugal cleaning of milk is carried out at 35... 45 "C, since in these conditions the deposition of mechanical contaminants is more effective due to an increase in the speed of movement of particles.

During centrifugal cleaning of milk along with mechanical contamination, a significant part of microorganisms is removed, which is explained by the difference in their physical properties. Bacterial cells have a size of 0.8... 6 μm, and the size of protein particles of milk is much smaller: even the largest of them - casein particles - reach a size of 0.1... 0.3 μm. In order to achieve the greatest degree of microbial cell removal, a separator-bacherio separator is provided. The efficiency of microorganism isolation on it reaches 98%.

1.1.4 Milk cooling modes

The quality of milk, especially its bacteriological characteristics, largely depends on the duration and temperature of its storage. It is known that fresh milk contains special bactericidal substances that not only prevent the growth of bacteria, but also destroy them. In uncooled milk, microorganisms that cause its skew quickly develop. So, at a temperature of 32 ° C after 10 hours, the acidity of milk increases by 2.8 times, and the number of bacteria increases by 40 times. In milk cooled to 12 "C, the acidity does not increase for 10 hours, and the total number of bacteria does not change significantly. Therefore, cooling of milk is one of the main factors contributing to the suppression of the development of undesirable pathogenic microflora and the preservation of milk quality.

The reproduction of most microorganisms found in milk slows sharply when it cools below 10 ° C and almost completely stops at a temperature of about 2... 4 ° C.

The optimal shelf life of milk cooled to 4... 6 ° С is no more than 12 h. With longer storage of milk under conditions of low temperatures, flavor and consistency defects occur.

Equipment

3.1.3 Single-circuit cooler for milk OP-1000M

Designed to cool milk in a continuous thin-layer closed stream to storage temperature. It consists of a plate heat exchanger and product temperature monitoring devices.

Performance, Leo 1000

Ice water coolant

Cold consumption, kWh 47

Ice water:

Flow rate, m3 h 3-4

Pressure, MPa 0.20.3

Temperature, 0 С 1-2

Overall dimensions, mm 850x500x1300 (0.425 m2)

Weight, 200 kg.

3.1.4 Capacity for acceptance and reservation of PM-B-2 milk

Designed for acceptance and storage of milk cooled to 60 С at dairy enterprises

Volume, m3 2

Frame type agitator agitator

Stirrer speed, min-1 17

Drive power, kW 0.75

Overall dimensions, mm 1510x1510x2110 (2.280m2)

Weight, kg 410

3.1.6 SELS-1,5M self-unloading separator

Designed for use at milk processing enterprises of small capacity when dividing whole milk with a temperature of 3550 ° C into cream and defatted milk with simultaneous cleaning from contaminants, as well as for normalizing milk by fat fraction.

Performance, l/h up to 1200

Fat content,%:

cream 18-45

normalized milk 1-3.5

Weight fraction of fat in

defatted milk,% 0.05

Drum:

weight, kg 57

diameter, mm 305

Volume of slurry space, dm3 0.8

Partial unloading time, from 0.10.2

Installed power, kW 2.2

Overall dimensions, mm 700x500x1140 ± 5 (0, 35m3)

Weight (without control panel), kg 250

Conclusion

Drinking milk is a popular food. In accordance with GOST R 52738, drinking milk is a milk product with a weight fraction of fat of no more than 9.0%, made of raw milk and/or dairy products, thermally treated by at least pasteurization.

Pasteurized milk is considered more useful. During pasteurization, the milk is heated to 6070 ° C, which allows you to save not only vitamins, but also most of the useful microorganisms and at the same time suspend the process of skipping milk. The shelf life of pasteurized milk is short - only 36 hours. In addition, heat treatment of milk (pasteurization) makes it possible to minimize the possibility of microorganisms to reproduce. The production of drinking milk in Russia, in general, is characterized by a fairly stable level. At the same time, recently there has been an increase in production volumes by 1.61.7% per year.

The heat treatment of milk at a temperature of up to 100 ° C was studied in detail by the French scientist Louis Pasteur and became known as "pasteurization." The goal of pasteurization of milk is to maximize the preservation of food qualities of the product and safe consumption of the product during the entire shelf life.

As a result, transmission through milk and dairy products of infectious diseases is excluded and longer shelf life is ensured. The shelf life of pasteurized dairy products is from 7 to 16 at a temperature of 24 ° C.

Pasteurized milk can be produced with fruit and other additives. Also, pasteurized milk can be produced from reconstituted milk. It differs in heat treatment, chemical composition, with or without the addition of fillers. It is produced in the following assortment: whole (normalized and restored), high fat, melted, protein, vitaminized and low-fat. The main type is whole milk with a fat weight fraction of at least 3.2%, but milk with an increased and reduced fat weight fraction of 4.0 is also produced; 6,0; 3,5; 2,5; 1,0%.

During this course work key points of primary, mechanical, heat treatment of milk transportation and storage were considered. The topic of milk processing technology is touched, the food calculation of drinking milk is made. The third chapter investigated the technological equipment of milk.

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