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Available Water
Water activity (''aw'') is the partial vapor pressure of water in a solution divided by the standard state partial vapor pressure of water. In the field of food science, the standard state is most often defined as pure water at the same temperature. Using this particular definition, pure distilled water has a water activity of exactly one. Water activity is the thermodynamic activity of water as solvent and the relative humidity of the surrounding air after equilibration. As temperature increases, ''aw'' typically increases, except in some products with crystalline salt or sugar. Water migrates from areas of high ''aw'' to areas of low ''aw''. For example, if honey (''aw'' ≈ 0.6) is exposed to humid air (''aw'' ≈ 0.7), the honey absorbs water from the air. If salami (''aw'' ≈ 0.87) is exposed to dry air (''aw'' ≈ 0.5), the salami dries out, which could preserve it or spoil it. Lower ''aw'' substances tend to support fewer microorganisms since these get desiccated by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Partial Pressure
In a mixture of gases, each constituent gas has a partial pressure which is the notional pressure of that constituent gas as if it alone occupied the entire volume of the original mixture at the same temperature. The total pressure of an ideal gas mixture is the sum of the partial pressures of the gases in the mixture ( Dalton's Law). The partial pressure of a gas is a measure of thermodynamic activity of the gas's molecules. Gases dissolve, diffuse, and react according to their partial pressures but not according to their concentrations in gas mixtures or liquids. This general property of gases is also true in chemical reactions of gases in biology. For example, the necessary amount of oxygen for human respiration, and the amount that is toxic, is set by the partial pressure of oxygen alone. This is true across a very wide range of different concentrations of oxygen present in various inhaled breathing gases or dissolved in blood; consequently, mixture ratios, like that of breat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Relative Humidity
Humidity is the concentration of water vapor present in the air. Water vapor, the gaseous state of water, is generally invisible to the human eye. Humidity indicates the likelihood for precipitation, dew, or fog to be present. Humidity depends on the temperature and pressure of the system of interest. The same amount of water vapor results in higher relative humidity in cool air than warm air. A related parameter is the dew point. The amount of water vapor needed to achieve saturation increases as the temperature increases. As the temperature of a parcel of air decreases it will eventually reach the saturation point without adding or losing water mass. The amount of water vapor contained within a parcel of air can vary significantly. For example, a parcel of air near saturation may contain 28 g of water per cubic metre of air at , but only 8 g of water per cubic metre of air at . Three primary measurements of humidity are widely employed: absolute, relative, and specific. A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Capacitance
Capacitance is the capability of a material object or device to store electric charge. It is measured by the change in charge in response to a difference in electric potential, expressed as the ratio of those quantities. Commonly recognized are two closely related notions of capacitance: ''self capacitance'' and ''mutual capacitance''. An object that can be electrically charged exhibits self capacitance, for which the electric potential is measured between the object and ground. Mutual capacitance is measured between two components, and is particularly important in the operations of the capacitor, a device designed for this purpose as an elementary linear electronic component. Capacitance is a function only of the geometry of the design of the capacitor, e.g., the opposing surface area of the plates and the distance between them, and the permittivity of the dielectric material between the plates. For many dielectric materials, the permittivity and thus the capacitance, is in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Powdered Milk
Powdered milk, also called milk powder, dried milk, or dry milk, is a manufactured dairy product made by evaporating milk to dryness. One purpose of drying milk is to preserve it; milk powder has a far longer shelf life than liquid milk and does not need to be refrigerated, due to its low moisture content. Another purpose is to reduce its bulk for the economy of transportation. Powdered milk and dairy products include such items as dry whole milk, nonfat (skimmed) dry milk, dry buttermilk, dry whey products and dry dairy blends. Many exported dairy products conform to standards laid out in ''Codex Alimentarius''. Powdered milk is used for food as an additive, for health (nutrition), and also in biotechnology (saturating agent). History and manufacture While Marco Polo wrote of Mongolian Tatar troops in the time of Kublai Khan who carried sun-dried skimmed milk as "a kind of paste", the first modern production process for dried milk was invented by the Russian doctor Osip Kr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kill Step
Kill often refers to: * Homicide, one human killing another *cause death, to kill a living organism, to cause its death Kill may also refer to: Media *''Kill!'', a 1968 film directed by Kihachi Okamoto * ''Kill'' (Cannibal Corpse album), 2006 * ''Kill'' (Electric Six album), 2009 * "Kill" (song), a 2008 song by Mell Places in Ireland Republic of Ireland * Kill, County Dublin *Kill, County Kildare *Kill, County Waterford *Kill, Kilbixy, County Westmeath *Kill, Kilcar, County Donegal *Kill, Kilcleagh, County Westmeath United Kingdom * Kill, County Tyrone, a townland in County Tyrone Sports * Baserunner kill, a baseball term *Penalty kill, an ice hockey term *Kill, a type of attack in volleyball Other uses * Kill (body of water) *Kill (command), a computing command See also * * * Keal (other) * Keel (other) * Keele (other) * Kiel (other) * Kil (other) * Kile (other) * Kyl (other) * Kyle (other) * Kyll * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intermediate Moisture Food
Intermediate moisture foods (IMF) are shelf-stable products that have water activities of 0.6-0.84, with a moisture content ranging from 15% - 40% and are edible without rehydration. These food products are below the minimum water activity for most bacteria (0.90), but are susceptible to yeast and mold growth. Historically, ancient civilizations would produce IMF using methods such as sun drying, roasting over fire and adding salt to preserve food for winter months or when preparing for travel. Currently, this form of processing is achieved by using one of four methods: partial drying, osmotic drying using a humectant, dry infusion and by formulation. A variety of products are classified as IMF, such as dried fruits, sugar added commodities, marshmallows, and pie fillings. Shelf-life and safety The purpose of IMF foods is to achieve a water activity that the food can be stored safely without refrigeration. However, the food is not sterile. '' Staphylococcus aureus'' i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Food And Drug Administration
The United States Food and Drug Administration (FDA or US FDA) is a List of United States federal agencies, federal agency of the United States Department of Health and Human Services, Department of Health and Human Services. The FDA is responsible for protecting and promoting public health through the control and supervision of food safety, tobacco products, caffeine products, dietary supplements, Prescription drug, prescription and Over-the-counter drug, over-the-counter pharmaceutical drugs (medications), vaccines, biopharmaceuticals, blood transfusions, medical devices, electromagnetic radiation emitting devices (ERED), cosmetics, Animal feed, animal foods & feed and Veterinary medicine, veterinary products. The FDA's primary focus is enforcement of the Federal Food, Drug, and Cosmetic Act (FD&C), but the agency also enforces other laws, notably Section 361 of the Public Health Service Act, as well as associated regulations. Much of this regulatory-enforcement work is not d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bacterial Growth
250px, Growth is shown as ''L'' = log(numbers) where numbers is the number of colony forming units per ml, versus ''T'' (time.) Bacterial growth is proliferation of bacterium into two daughter cells, in a process called binary fission. Providing no event occurs, the resulting daughter cells are genetically identical to the original cell. Hence, bacterial growth occurs. Both daughter cells from the division do not necessarily survive. However, if the surviving number exceeds unity on average, the bacterial population undergoes exponential growth. The measurement of an exponential bacterial growth curve in batch culture was traditionally a part of the training of all microbiologists; the basic means requires bacterial enumeration (cell counting) by direct and individual (microscopic, flow cytometry), direct and bulk (biomass), indirect and individual (colony counting), or indirect and bulk (most probable number, turbidity, nutrient uptake) methods. Models reconcile theory with th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Water Content
Water content or moisture content is the quantity of water contained in a material, such as soil (called soil moisture), rock, ceramics, crops, or wood. Water content is used in a wide range of scientific and technical areas, and is expressed as a ratio, which can range from 0 (completely dry) to the value of the materials' porosity at saturation. It can be given on a volumetric or mass (gravimetric) basis. Definitions Volumetric water content, θ, is defined mathematically as: :\theta = \frac where V_w is the volume of water and V_\text = V_s + V_w + V_a is equal to the total volume of the wet material, i.e. of the sum of the volume of solid host material (e.g., soil particles, vegetation tissue) V_s, of water V_w, and of air V_a. Gravimetric water content is expressed by mass (weight) as follows: :u = \frac where m_w is the mass of water and m_s is the mass of the solids. For materials that change in volume with water content, such as coal, the gravimetric water content, ''u' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hazard Analysis And Critical Control Points
Hazard analysis and critical control points, or HACCP (), is a systematic preventive approach to food safety from biological, chemical, and physical hazards in production processes that can cause the finished product to be unsafe and designs measures to reduce these risks to a safe level. In this manner, HACCP attempts to avoid hazards rather than attempting to inspect finished products for the effects of those hazards. The HACCP system can be used at all stages of a food chain, from food production and preparation processes including packaging, distribution, etc. The Food and Drug Administration (FDA) and the United States Department of Agriculture (USDA) require mandatory HACCP programs for juice and meat as an effective approach to food safety and protecting public health. Meat HACCP systems are regulated by the USDA, while seafood and juice are regulated by the FDA. All other food companies in the United States that are required to register with the FDA under the Public Health ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Critical Control Point
Critical Control Point (CCP) is the point where the failure of Standard Operation Procedure (SOP) could cause harm to customers and to the business, or even loss of the business itself. It is a point, step or procedure at which controls can be applied and a food safety hazard can be prevented, eliminated or reduced to acceptable (critical) levels. The most common CCP is cooking, where food safety managers designate critical limits. CCP identification is also an important step in risk and reliability analysis for water treatment processes. Food in cooking In the United States, the Food and Drug Administration (FDA) establishes minimum internal temperatures for cooked foods. These values can be superseded by state or local health code requirements, but they cannot be below the FDA limits. Temperatures should be measured with a probe thermometer in the thickest part of meats, or the center of other dishes, avoiding bones and container sides. Minimum internal temperatures are set a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ingredient
An ingredient is a substance that forms part of a mixture (in a general sense). For example, in cooking, recipes specify which ingredients are used to prepare a specific dish. Many commercial product (business), products contain secret ingredients that are purported to make them better than competing products. In the pharmaceutical industry, an active ingredient is that part of a Pharmaceutical formulation, formulation that yields the effect expected by the customer. Sovereign state, National laws usually require prepared food products to display a list of ingredients, and specifically require that certain food additive, additives be listed. In most developed countries, the law requires that ingredients be listed according to their relative weight in the product. If an ingredient itself consists of more than one ingredient (such as the cookie pieces which are a part of "cookies and cream" flavor ice cream), then that ingredient is listed by what percentage of the total product ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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