Food Hygiene - Benghazi University PDF

Bengha zi University Faculty of public Health Department of Nutrition Food Hygiene Fourth year 2023-2024 By: Mariam AL-Jarrari. 10/February/2024  Water hygiene Universal and equitable access to...

Bengha zi University Faculty of public Health Department of Nutrition Food Hygiene Fourth year 2023-2024 By: Mariam AL-Jarrari. 10/February/2024  Water hygiene Universal and equitable access to sufficient amounts of safe drinking water and adequate sanitation are basic human rights.their achievement is fundamental in promoting health, well-being, dignity and development, and a foundation for creating healthy and resilient communities. The following are general categories of drinking water contaminants and examples of each:  Physical contaminants primarily impact the physical appearance or other physical properties of water. Examples of physical contaminants are sediment or organic material suspended in the water of lakes, rivers and streams from soil erosion.  Chemical contaminants are elements or compounds. These contaminants may be naturally occurring or man-made. Examples of chemical contaminants include nitrogen, bleach, salts, pesticides, metals, toxins produced by bacteria, and human or animal drugs.  Biological contaminants are organisms in water. They are also referred to as microbes or microbiological contaminants. Examples of biological or microbial contaminants include bacteria, viruses, protozoa, and parasites.  Radiological contaminants are chemical elements with an unbalanced number of protons and neutrons resulting in unstable atoms that can emit ionizing radiation. Examples of radiological contaminants include cesium, plutonium and uranium. Water borne diseases: Exposure to contaminated water can lead to adverse health effects from waterborne illnesses. Swimming or fishing in polluted water sources and consumption of affected seafood are the most common pathways of exposure. Some common water-related illnesses are:  Diarrhea.  Giardiasis.  Dysentery.  Typhoid fever  E. Coli infection.  Salmonellosis. 1 Food Hygiene – By: Mariam Al-Jarrari. Adverse health effects can include pain in the gastrointestinal, reproductive, neurological systems, and other symptoms. Continuous exposure can have long- lasting health impacts. Water quality parameters: 1. Physical parameters: a. Turbidity: Though less used than some of the other water quality parameters on this list, turbidity refers to how cloudy water is. When using Turbidity sensors, these devices are designed to measure the ability that light has to pass through water. High levels of turbidity can occur as a result of higher concentrations of silt, clay, and organic materials. The main issue with turbidity in water is that the water will look bad. b. Temperature: Some of the aspects of water quality that are influenced by the water’s temperature include odors, chemical reactions, solubility, palatability, and viscosity. As such, biological oxygen demand, sedimentation, and chlorination all depend on the water’s temperature. The ideal water temperatures range from 50-60 degrees Fahrenheit (10-15.5 0C). c. Color: It’s possible for the color of the water to be altered by materials that decay from organic matter, the primary of which include vegetation. Such inorganic matter as rocks, soil, and stones may also affect the color of the water. Even though these changes to a water’s color may create aesthetic issues with the water, they don’t change how the water tastes. When attempting to identify the color of water, it’s important to understand the difference between the water’s apparent color and its true color.  Apparent color is made up of suspended material and dissolved solid colors.  The true color of water can be identified after all suspended materials have been filtered out of the water. d. Taste and Odor: It’s possible for the taste of water to change and for odors to develop as a result of foreign matter being introduced to the water. 2 Food Hygiene – By: Mariam Al-Jarrari.  This matter can include:  Organic materials.  Dissolved gases.  Inorganic compounds. Most of this matter is derived from agricultural, natural, and domestic sources. e. Total Dissolved Solids (TDS): Total dissolved solids (TDS) is a measure of the dissolved combined content of all inorganic and organic substances present in a liquid in molecular, ionized, or micro-granular (colloidal sol) suspended form. Total dissolved solids in water supplies originate from natural sources, sewage, urban and agricultural runoff and industrial wastewater. Table: Levels of TDS and water quality. Quality of water TDS Levels High quality. 300 mg/L or less. Good 300 – 600 mg/ L Poor 600 – 900 mg/L Unacceptable Above 1200 mg /L f. Electrical Conductivity: Another core physical parameter that should be measured is electrical conductivity, which measures how well a sample of water or similar solution can carry or conduct electrical currents. Conductivity levels will increase as the amount of ions in the water increases. 2. Chemical parameters: 1. PH: PH is one of the first measurements that should be take when measuring safety and quality of water. Pure water has a neutral PH. However, rainfall is somewhat more acidic and typically has a 5.6 PH. Water is considered to be safe to drink if it has a pH of (6.5- 8.5). 3 Food Hygiene – By: Mariam Al-Jarrari.  2. Acidity: Acidity is commonly caused by the presence of:  Mineral acids.  Hydrolyzed salts  Carbon dioxide. When acids are introduced to water, they can influence many different processes, which include everything from biological activities and chemical reactions to corrosion. 3. Alkalinity: In the event that water is alkaline, this means that it has a pH that’s at least higher than 7.0. The presence of bicarbonate ions, carbonate ions, and hydroxide ions increases the alkalinity of water. If the water samples have high alkalinity or acidity, this indicates that the water is contaminated in some way. 4. Chlorine: While chlorine doesn’t occur naturally in water, it’s commonly added to wastewater for disinfection purposes. Even though base chlorine is a toxic gas, the aqueous solution is completely harmless to humans. If a small amount of chlorine is found in water, this indicates that the water is clean and essentially free from contaminants. 5. Hardness: Hardness occurs when water contains high mineral levels (magnesium and calcium) ions, which can enter water from rock and soil. In most cases, groundwater has more hardness to it than surface water. 6. Dissolved Oxygen (DO): When water has a high concentration of dissolved oxygen, that’s indicates the water quality is high. Dissolved oxygen occurs because of the solubility of oxygen. The amount of DO that can find in water depends on numerous factors, the primary of which include the water’s salinity, pressure, and temperature. 7. Biological Oxygen Demand: Microorganisms use organic matter as a source of food. When this material is metabolized, oxygen is consumed. If this process takes place in water, the dissolved oxygen in a sample of the water will be consumed. 4 Food Hygiene – By: Mariam Al-Jarrari.  In the event that there is a substantial amount of organic matter in the water, high amounts of dissolved oxygen will be consumed in order to make sure that the organic matter decomposes. However, this creates problems since aquatic plants and animals require DO to survive. 3. Biological parameters: a. Bacteria: High levels of bacteria in water can lead to many harmful waterborne diseases, including cholera, tularemia and typhoid. b. Algae: Algae are ideally suited for water quality assessment because they have rapid reproduction rates and very short life cycles, making them valuable indicators of short-term impacts. Excess growth of algae in water indicates polluted water; since water soluble compounds containing nitrate, phosphate, and ammonium ions can cause excessive growth of algae and other aquatic plants, which die, decay, deplete dissolved oxygen in water thereby killing fish. c. Viruses: Certain waterborne viruses can cause hepatitis and similar health problems. Despite the difficulty in treating viruses, most water treatment facilities should be able to eliminate viruses during the disinfection process. Water purification: Water purification refers to "the process of removing undesirable chemicals, biological contaminants, suspended solids, and gases from water". The aim of water purification is to produce and maintain water that is: Hygienically safe. Aesthetically attractive and palatable. In an economical manner. Public water systems often use a series of water treatment steps that include: 1. Coagulation and flocculation: The first step in the water purification process is coagulation and flocculation. At this stage, chemicals such as aluminum sulfate or ferric chloride are added, which 5 Food Hygiene – By: Mariam Al-Jarrari. allow the solid particles to group together forming flocs. These flocs are easier to remove later. 2. Sedimentation: Once the flocs have formed, the water passes through a settling tank. Here, the flocs settle to the bottom of the tank due to gravity, forming a sludge. The clarified water is separated from the sludge and moves to the next stage. 3. Filtration: Filtration is a crucial stage in the water purification process. The clarified water passes through different filtration media, such as sand, activated carbon and gravel. These media retain fine particles and microorganisms that may still be present in the water. 4. Disinfection: Once filtered, the water goes through a disinfection process to eliminate any pathogenic microorganisms that may be present. The most common method of disinfection is chlorination, where chlorine or its derivatives are added to water to eliminate bacteria, viruses and other microorganisms. 5. PH adjustment: In some cases, purified water may have an unbalanced pH or lack essential minerals. At this stage, the pH of the water is adjusted and minerals are added to achieve a proper balance and ensure the organoleptic quality of the water. 6 Food Hygiene – By: Mariam Al-Jarrari.