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Microbiology of raw milk and milk after treatment
Pláničková, Jana ; Vítová, Eva (referee) ; Omelková, Jiřina (advisor)
The aim of this bachelor thesis is microbiology of raw milk and heat treatment milk, pasteurized and UHT treatment. There are described the most important and the most common microorganisms that contaminate milk, spoilage and pathogenic in the theoretical part. Practical part was provided in laboratory of diary factory. There were determined counts of microorganisms in raw, pasteurized and UHT milk by microbiological analysis.
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Microbiology of raw milk and selected dairy products
BEZÁNYIOVÁ, Michaela
Milk is an important part of the human diet due to its composition. The aim of the bachelor thesis was to create a review focused on the microbiota of raw cow's milk and dairy products. The thesis summarizes the ways of primary and secondary microbial contamination of milk and describes the intrinsic and extrinsic factors influencing the growth of microorganisms. A particular attention is focused on mastitis, which are the main source of primary contamination of milk. The great emphasis is attended to the necessity of strict following of hygiene regulations during manipulation with this raw material. In the last part, potential health risks associated with consumption of milk and dairy products is mentioned. .
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Patogénne mikroorganizmy v surovom mlieku
Strnadová, Ivana
This thesis analyses the occurrence of the pathogenic microorganisms in raw milk. The theoretical part of this thesis focuses on the description of the particular microorganisms, their biochemical activity, their source and the transmission. Furthermore, this thesis analyses the diseases related to these particular microorganisms. In addition, this study discusses a legislation of the raw milk distribution and trade with a focus on its benefits and threats for the final consumers. The practical part includes an analysis of the total number of microorganisms, psychrotrophic bacteria, bacteria Salmonella spp., bacteria Listeria monocytogenes, Staphylococcus aureus and Escherichia coli in raw milk. The samples for this study were collected from the milk automats in the South Moravian region and from the farm in the Pardubice region. Samples were collected during the following year periods: autumn/winter, spring/summer. The analysis includes a comparison of the samples with the legislative limits. Furthermore, the samples were compared with each other in according to the particular period of the year. The last stage of the analysis determines the presence of the inhibitory substances in raw milk.
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Legislative requirements for milk quality in the Czech Republic
Škvorová, Kamila ; Hejtmánková, Alena (advisor) ; Michlová, Tereza (referee)
The aim of the thesis was to give a comprehensive review of literature dealing with legislative measures, milk production in terms of sales of milk and its storage. We used the most current Czech and European legislation. These sources have been supplemented thematically compliant scientific and professional publications.
Milk is a primary since the Middle Ages and sought food which people consume every day. Along with dairy milk a deserved popularity mainly due to its rich composition and nutritional and health properties. The main components of milk include water, lactose, fat, protein and minerals. Milk however can also include foreign substances of organic and inorganic origin and unwanted microflora. Microorganisms are particularly dangerous to humans and are considered a major source of foodborne illnesses. To eliminate unwanted microflora, extending shelf life and maintain public safety is used heat treatment, including pasteurization and treatment of very high temperature (UHT). This treatment must be carried out according to established requirements and specifications.
If a consumer buys a dairy product in the Czech Republic retains its quality as well. All animal products, including products imported to the Czech market, are compulsorily fitted with oval health mark, which ensures wholesomeness. The quality of the milk is influenced by many factors, most of which are closely linked, and therefore not always easy to identify the specific cause possible reduction in quality standards. Already during the production process, emphasis is put on prevention in the field of quality and safety. Security is guaranteed by a system of determining critical control points HACCP, which is in the Czech Republic and the EU compulsory by law. Among the optional systems include ISO. Most enterprises with good reputation has introduced both these systems. Simultaneous application of HACCP and ISO standards provides a guarantee for the security of the overall quality and safety of products. This connection is known as TQM system.
The main indicators of quality of raw milk are total number of mesophilic microorganisms, somatic cell count, fat content, crude protein residues of inhibiting substances, the average herd size and the number of bred cows. The milk must not contain any preservatives or stabilizers. Meeting the requirements and quality criteria will be checked on the appropriate number of samples that are collected in enterprises producing milk, random checks.
The basic quality criteria of raw milk, food business operators must ensure that:
The content of microorganisms in 1 mL at 30 ° C must be < 100 000. It is found average values for two months for the collection of at least two samples per month.
Somatic cells in 1 ml at 30 ° C must be < 400 000. It is obtained by moving the geometric mean for the three months, every month, evaluates at least one sample.
Immediately before treating the milk must contain 1 ml < 300000 microorganisms at 30 ° C. In the treated milk that is used for the manufacture of other dairy products, may be the content of microorganisms in 1 ml> 100,000 at 30 ° C.
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Heat treatment of milk and its importance
VOČADLOVÁ, Kateřina
The aim of this work is to assess the public knowledge of heat treatment, its purpose and effect on milk quality and to find out their attitude to raw milk consumption. Heat treatment of milk is a commonly used part of dairy processing. Although the heat treatment has a significant impact on ensuring microbial quality, safety and shelf life of milk, its application still face a public disagreement, primary in connection with potential health benefits, which are lost during heat treatment. The survey took place (from November 2015 to February 2016) in a randomly selected group of respondents (n=265). It was found that 22 % of respondents buy raw (unpasteurized) milk and only 27 % of them reported pasteurizing of the milk before consumption. 68 % of respondents just cool the milk down and consume it without any thermal treatment. 23 % of respondents though that pasteurization has negative effects on milk quality and 21 % of respondents said that consumption of milk pose no health risk.
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Influence of cold chain interruption on microorganisms growth in milk
BEEROVÁ, Michaela
Raw milk is one of the most monitored product not only in terms of microbial, but also in terms of technology, chemistry and sensory. The aim of the thesis was the examination of the influence of cold chain interruptions on dynamic of total bacteria count (TBC) in raw cow milk. The results show that the temperature and time have a significant impact on TBC. The samples stored during the first three hours of experiment at 15 °C showed (in time 0 - 27 hours) a continuous growth with changing dynamic (5.13, 6.66, resp. log CFU/ml). The samples stored at 30 °C showed a significant increase, however there was a decrease between an hour of 25th and 26th (6.88, 6.69, resp. log CFU/ml). An hour later another increase was found (to 7.37 log CFU/ml). The samples stored at 6 °C showed the lowest values of TBC, although an increase was found after 24 hours (5.87 log CFU/ml). The second part of the thesis was an evaluation of the questionnaire survey among people consuming raw cow milk from a vending machine. The survey showed that more than a half of respondents (88%) interrupt the cold chain for no more than an hour. Then it was found that 75% of respondents do not overcook raw milk. The consumers appreciate the taste of raw milk (35%), freshness (19%), quality (16%), and a nutritional value (12%).
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Microbiology of raw milk and milk after treatment
Pláničková, Jana ; Vítová, Eva (referee) ; Omelková, Jiřina (advisor)
The aim of this bachelor thesis is microbiology of raw milk and heat treatment milk, pasteurized and UHT treatment. There are described the most important and the most common microorganisms that contaminate milk, spoilage and pathogenic in the theoretical part. Practical part was provided in laboratory of diary factory. There were determined counts of microorganisms in raw, pasteurized and UHT milk by microbiological analysis.
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Mikrobiologie kozího a ovčího mléka a sýrů vyráběných na farmách
Zatloukalová, Růžena
The thesis summarizes findings about the microbiology of goat and sheep milk and of farm produced cheese. It describes the production of selected groups of cheeses. It deals with particular microorganisms which are important with respect to technology and which are contained in primary and secondary cultures. It characterizes the undesirable microorganisms which cause contamination and it presents the possible measures to fight with them. Last but not least, there are described the legislative requirements for the farm processing of milk and cheese. The chosen groups of microorganisms were experimentally determined by cultivation methods in samples of raw goat and sheep milk and cheese. It was found out that in some months the values of CPM in milk exceeded the limit given by the Orders of the European Parliament and Counsel 853/2004. The discovered presence of enterococci, coliform bacteria, thermo-resistant aerobic and anaerobic bacteria and other undesirable microorganisms in raw milk and cheese points to the insufficient adherence of hygienic principals and technical procedure.
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Important food-borne pathogens in raw cow´s milk
HRUBEŠOVÁ, Kristýna
This work talks about the problems of food-borne pathogens in raw milk, with a special focus on Campylobacter jejuni and Staphylococcus aureus including its negative influence on health of the consumers. The topic of consumption of raw milk was lately a much discussed question and is further described in the text. With consideration to possible occurrence of food-borne pathogens, it is important to thermally treat raw milk before consumption. Despite this fact there is still a large number of consumers who don?t respect this technical procedure and they threaten their own health.
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Factors affecting quality of raw cow´s milk during milking and storage at farm
HAVRÁNKOVÁ, Iveta
Milk is one of the few products which we can use for direct consumption. Not only is it important for human nutrition as a raw product, but it also finds an increasing usage in food industry. The quality of milk is affected by various factors. This work deals only with the most important ones, which have an influence on the nutrition value as well as on the microbiological and hygienic quality of milk.
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