bacteriology of water milk and food pdf

Bacteriology Of Water Milk And Food Pdf

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Introduction to the Microbiology of Food

Beresford, R. Paul Ross, Gerald F. Fitzgerald, Paul D. Here, we review what is known about the microorganisms present in raw milk, including milk from cows, sheep, goats and humans. Milk, due to its high nutritional content, can support a rich microbiota. These microorganisms enter milk from a variety of sources and, once in milk, can play a number of roles, such as facilitating dairy fermentations e.

Microorganisms are living organisms that are individually too small to see with the naked eye. Microorganisms are found everywhere ubiquitous and are essential to many of our planets life processes. With regards to the food industry, they can cause spoilage, prevent spoilage through fermentation, or can be the cause of human illness. Bacteria are relatively simple single-celled organisms. One method of classification is by shape or morphology:. There exists a bacterial system of taxonomy, or classification system, that is internationally recognized with family, genera and species divisions based on genetics.

Pasteurization

Bacteria are the most important microorganisms to the food processor. Most are harmless, many are highly beneficial, some indicate the probable presence of filth, disease organisms, spoilage and a few cause disease. There are thousands of species of bacteria, but all are single-celled and fall into three basic shapes: spherical, straight rods, and spiral rods. To see them, you need a microscope that magnifies about fold. All bacteria reproduce by dividing into two cells.

Methylene Blue Dye Reduction Test for Assessing the Raw Milk Quality

Metrics details. Urban water sources of Khamis Mushait Governorate, southwestern Saudi Arabia, were studied to assess their bacteriological characteristics and suitability for potable purposes. A cross-sectional epidemiological method was adopted to investigate the four main urban water sources i. These were sampled and examined between February and June

Dairy Microbiology

Faecal pollution of water supplies may lead to introduction of a variety of intestinal pathogens that comprise water-borne diseases Table While evaluating faecal pollution of water supplies, one has to keep in view the bacterial flora in water Table The coliforms ferment lactose, e.

Bacteriological water analysis

Testing for coliforms has a long history in the dairy industry and has helped to identify raw milk and dairy products that may have been exposed to unsanitary conditions. Coliform standards are included in a number of regulatory documents e. As a consequence, detection above a threshold of members of this method-defined, but diverse, group of bacteria can result in a wide range of regulatory outcomes.

Bacterial count in prepared food or water is a key factor in assessing the quality and safety of food. It also reveals the level of hygiene adopted by food handlers in the course of preparation of such foods. This comparative study evaluated the bacteriological quality of food and water consumed in Nsukka, Enugu state, Nigeria, using three bacteria enumeration methods. Data obtained are assumed to reflect the level of personal and environmental hygiene in the study population. Ten types of foods—beans, yam, abacha, okpa, moimoi, pear, cassava foofoo , rice, agidi, and garri —and 10 water samples were evaluated for bacteriological quality, precisely determining the level of coliform contamination, using the most probable number MPN , lactose fermentation count LFC , and Escherichia coli count ECC methods. However, this did not differ significantly in the three methods used for the enumeration of coliforms, suggesting that any of the three methods could be validly used for such studies with confidence. Escherichia coli and Klebsiella pneumoniae were the two major coliforms identified among 98 coliform isolates obtained from the various food samples, of which 78

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The process is intended to destroy or deactivate organisms and enzymes that contribute to spoilage or risk of disease, including vegetative bacteria , but not bacterial spores. The process was named after the French microbiologist, Louis Pasteur , whose research in the s demonstrated that thermal processing would deactivate unwanted microorganisms in wine. Today, pasteurization is used widely in the dairy industry and other food processing industries to achieve food preservation and food safety. By the year , most liquid products were heat treated in a continuous system where heat can be applied using a plate heat exchanger or the direct or indirect use of hot water and steam. Due to the mild heat, there are minor changes to the nutritional quality and sensory characteristics of the treated foods.

We can test your water for the presence or absence of coliforms and E. See Environmental Sciences Branch tests to find out about testing for chemicals. Bottles can be acquired from Laboratory Specimen Receiving. A good location for taking water samples is an outside faucet that does not leak avoid rubber hoses, fire hydrants, dirty areas, and areas behind bushes. Do not take samples from kitchen or bathroom sinks.

The numbered list below identifies seven types of bacteria according to how they change the properties of milk. Often these changes are negative spoilage but as we will see in later sections, many of these bacteria are important to the development of cheese flavour. Before proceeding to the list, please note the following definitions:. Keeping the above definitions in mind, note the following types of microorganisms, grouped according to their impact on milk quality. For now note the following:. Most important in cheese milk are species of:.

Dairy Microbiology

Milk is synthesized in specialized cells of the mammary gland and is virtually sterile when secreted into the alveoli of the udder Tolle, Beyond this stage of milk production, microbial contamination can generally occur from three main sources Bramley and McKinnon, : from within the udder, from the exterior of the udder, and from the surface of milk handling and storage equipment. The health and hygiene of the cow, the environment in which the cow is housed and milked, and the procedures used in cleaning and sanitizing the milking and storage equipment are all key in influencing the level of microbial contamination of raw milk.

The water used during handling and processing of milk products can be potential sources of microbial contamination with possible negative consequences on food safety.

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