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Blast Freezing
Snap freezing (or cook-chill or blast freezing) is the process of rapid cooling of a substance for the purpose of preservation. It is widely used in the culinary and scientific industries. Culinary uses Cooked meals can be preserved by rapid freezing after cooking is complete. The main target group for these products are those with little time for cooking such as schools, prisons, and hospitals. The process involves the cooking of meals at a central factory then rapidly chilling them for storage until they are needed. Snap frozen foods need to be packed in shallow trays to make the process more efficient. The food is cooled to a temperature under 3 degrees Celsius within 90 minutes of cooking and stored at a temperature of 0 to 3 degrees Celsius. The meals can then be transported in refrigerated transport to where the food is to be reheated and consumed when needed. The length of storage depends on the method used but is usually five days. For longer storage the food may be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cooking
Cooking, cookery, or culinary arts is the art, science and craft of using heat to Outline of food preparation, prepare food for consumption. Cooking techniques and ingredients vary widely, from grilling food over an open fire to using electric stoves, to baking in various types of ovens, reflecting local conditions. Types of cooking also depend on the skill levels and training of the Cook (profession), cooks. Cooking is done both by people in their own dwellings and by professional cooks and chefs in restaurants and other food establishments. Preparing food with heat or fire is an activity unique to humans. Archeological evidence of cooking fires from at least 300,000 years ago exists, but some estimate that humans started cooking up to 2 million years ago. The expansion of agriculture, commerce, trade, and transportation between civilizations in different regions offered cooks many new ingredients. New inventions and technologies, such as the invention of pottery for holding ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
School
A school is an educational institution designed to provide learning spaces and learning environments for the teaching of students under the direction of teachers. Most countries have systems of formal education, which is sometimes compulsory. In these systems, students progress through a series of schools. The names for these schools vary by country (discussed in the '' Regional terms'' section below) but generally include primary school for young children and secondary school for teenagers who have completed primary education. An institution where higher education is taught is commonly called a university college or university. In addition to these core schools, students in a given country may also attend schools before and after primary (elementary in the U.S.) and secondary (middle school in the U.S.) education. Kindergarten or preschool provide some schooling to very young children (typically ages 3–5). University, vocational school, college or seminary may be avail ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prisons
A prison, also known as a jail, gaol (dated, standard English, Australian, and historically in Canada), penitentiary (American English and Canadian English), detention center (or detention centre outside the US), correction center, correctional facility, lock-up, hoosegow or remand center, is a facility in which inmates (or prisoners) are confined against their will and usually denied a variety of freedoms under the authority of the state as punishment for various crimes. Prisons are most commonly used within a criminal justice system: people charged with crimes may be imprisoned until their trial; those pleading or being found guilty of crimes at trial may be sentenced to a specified period of imprisonment. In simplest terms, a prison can also be described as a building in which people are legally held as a punishment for a crime they have committed. Prisons can also be used as a tool of political repression by authoritarian regimes. Their perceived opponents may be impri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hospital
A hospital is a health care institution providing patient treatment with specialized health science and auxiliary healthcare staff and medical equipment. The best-known type of hospital is the general hospital, which typically has an emergency department to treat urgent health problems ranging from fire and accident victims to a sudden illness. A district hospital typically is the major health care facility in its region, with many beds for intensive care and additional beds for patients who need long-term care. Specialized hospitals include trauma centers, rehabilitation hospitals, children's hospitals, seniors' (geriatric) hospitals, and hospitals for dealing with specific medical needs such as psychiatric treatment (see psychiatric hospital) and certain disease categories. Specialized hospitals can help reduce health care costs compared to general hospitals. Hospitals are classified as general, specialty, or government depending on the sources of income received. A teachi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meal
A meal is an eating occasion that takes place at a certain time and includes consumption of food. The names used for specific meals in English vary, depending on the speaker's culture, the time of day, or the size of the meal. Although they can be eaten anywhere, meals typically take place in homes, restaurants, and cafeterias. Regular meals occur on a daily basis, typically several times a day. Special meals are usually held in conjunction with such occasions as birthdays, weddings, anniversaries, and holidays. A meal is different from a snack in that meals are generally larger, more varied, and more filling than snacks. The type of food that is served or consumed at any given time depends on regional customs. Three main meals are often eaten in the morning, early afternoon, and evening in most modern civilizations. Further, the names of meals are often interchangeable by custom as well. Some serve dinner as the main meal at midday, with supper as the late afternoon/early eve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pasteurization
Pasteurization or pasteurisation is a process of food preservation in which packaged and non-packaged foods (such as milk and fruit juices) are treated with mild heat, usually to less than , to eliminate pathogens and extend shelf life. The process is intended to destroy or deactivate microorganisms and enzymes that contribute to food spoilage or risk of disease, including vegetative bacteria, but most bacterial spores survive the process. The process is named after the French microbiologist Louis Pasteur whose research in the 1860s demonstrated that thermal processing would deactivate unwanted microorganisms in wine. Spoilage enzymes are also inactivated during pasteurization. Today, pasteurization is used widely in the dairy industry and other food processing industries to achieve food preservation and food safety. By the year 1999, most liquid products were heat treated in a continuous system where heat can be applied using a plate heat exchanger or the direct or indirec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hygiene
Hygiene is a series of practices performed to preserve health. According to the World Health Organization (WHO), "Hygiene refers to conditions and practices that help to maintain health and prevent the spread of diseases." Personal hygiene refers to maintaining the body's cleanliness. Hygiene activities can be grouped into the following: home and everyday hygiene, personal hygiene, medical hygiene, sleep hygiene and food hygiene. Home and every day hygiene includes hand washing, respiratory hygiene, food hygiene at home, hygiene in the kitchen, hygiene in the bathroom, laundry hygiene and medical hygiene at home. Many people equate hygiene with 'cleanliness,' but hygiene is a broad term. It includes such personal habit choices as how frequently to take a shower or bath, wash hands, trim fingernails, and wash clothes. It also includes attention to keeping surfaces in the home and workplace clean, including bathroom facilities. Some regular hygiene practices may be considered good ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pathogens
In biology, a pathogen ( el, πάθος, "suffering", "passion" and , "producer of") in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ. The term ''pathogen'' came into use in the 1880s. Typically, the term ''pathogen'' is used to describe an ''infectious'' microorganism or agent, such as a virus, bacterium, protozoan, prion, viroid, or fungus. Small animals, such as helminths and insects, can also cause or transmit disease. However, these animals are usually referred to as parasites rather than pathogens. The scientific study of microscopic organisms, including microscopic pathogenic organisms, is called microbiology, while parasitology refers to the scientific study of parasites and the organisms that host them. There are several pathways through which pathogens can invade a host. The principal pathways have different episodic time frames, but soil has the longest ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Liquid Nitrogen
Liquid nitrogen—LN2—is nitrogen in a liquid state at low temperature. Liquid nitrogen has a boiling point of about . It is produced industrially by fractional distillation of liquid air. It is a colorless, low viscosity liquid that is widely used as a coolant. Physical properties The diatomic character of the N2 molecule is retained after liquefaction. The weak van der Waals interaction between the N2 molecules results in little interatomic interaction, manifested in its very low boiling point. The temperature of liquid nitrogen can readily be reduced to its freezing point by placing it in a vacuum chamber pumped by a vacuum pump. Liquid nitrogen's efficiency as a coolant is limited by the fact that it boils immediately on contact with a warmer object, enveloping the object in an insulating layer of nitrogen gas bubbles. This effect, known as the Leidenfrost effect, occurs when any liquid comes in contact with a surface which is significantly hotter than its boiling ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, responding to stimuli, providing structure to cells and organisms, and transporting molecules from one location to another. Proteins differ from one another primarily in their sequence of amino acids, which is dictated by the nucleotide sequence of their genes, and which usually results in protein folding into a specific 3D structure that determines its activity. A linear chain of amino acid residues is called a polypeptide. A protein contains at least one long polypeptide. Short polypeptides, containing less than 20–30 residues, are rarely considered to be proteins and are commonly called peptides. The individual amino acid residues are bonded together by peptide bonds and adjacent amino acid residues. The sequence of amino acid residue ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cell (biology)
The cell is the basic structural and functional unit of life forms. Every cell consists of a cytoplasm enclosed within a membrane, and contains many biomolecules such as proteins, DNA and RNA, as well as many small molecules of nutrients and metabolites.Cell Movements and the Shaping of the Vertebrate Body in Chapter 21 of Molecular Biology of the Cell '' fourth edition, edited by Bruce Alberts (2002) published by Garland Science. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos. It is also common to describe small molecules such as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flash Freezing
In physics and chemistry, flash freezing is the process whereby objects are frozen in just a few hours by subjecting them to cryogenic temperatures, or through direct contact with liquid nitrogen at . It is commonly used in the food industry. Flash freezing is of great importance in atmospheric science, as its study is necessary for a proper climate model for the formation of ice clouds in the upper troposphere, which effectively scatter incoming solar radiation and prevent Earth from becoming overheated by the sun. The process is also closely related to classical nucleation theory, which helps in understanding many materials, phenomena and theories in related situations. Overview When water is supercooled to temperatures below , it must freeze. When water is in a conventional freezer, a dynamic phase transition is triggered. The resulting ice depends on how quickly the system is cooled: If the water is cooled below its freezing point slowly, an ice crystal will result, ra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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