1. UNIT 5 Food hazards NOTES.docx

**UNIT 5** **Food safety and Ethics** **(Syllubus - Food safety: Food Hazards, Food Additives, Food Allergens Drugs, Hormones, and Antibiotics in Animals. Factors That Contribute to Foodborne Illness, Consumer Lifestyles and Demand, Food Production and Economics, History of Food Safety, The Role o...

**UNIT 5** **Food safety and Ethics** **(Syllubus - Food safety: Food Hazards, Food Additives, Food Allergens Drugs, Hormones, and Antibiotics in Animals. Factors That Contribute to Foodborne Illness, Consumer Lifestyles and Demand, Food Production and Economics, History of Food Safety, The Role of Food Preservation in Food Safety. Ethics: Clinical ethics, Health policy, Reaserch ethics, ethics on Animals. Biosafety and Bioethics).** Food safety is a scientific discipline describing handling, preparation, and storage of food in ways that prevent food borne. **Importances of food safety and hygiene** - Prevent food spoilage, i.e. changes that make food unfit for consumption due to microbial or chemical contamination. - Inform and educate people about simple and practical methods of keeping food safe to protect themselves against foodborne diseases. - Protect food from adulteration (intentional contamination). - Ensure proper practice in the food trade to prevent the sale of food that is offensive or defective in value and quality **Food hazards** Food hazards refer to any biological, chemical, or physical agent in food that may cause harm to the consumer. It\'s crucial to identify and manage these hazards to ensure the safety and quality of the food supply. Here are the main types of food hazards: **Biological Hazards:** Bacteria: Pathogenic bacteria such as Salmonella, Escherichia coli (E. coli), Listeria, and Campylobacter can cause foodborne illnesses. Viruses: Norovirus, Hepatitis A, and other viruses can contaminate food, especially through contact with infected food handlers. Parasites: Protozoa, roundworms, and flatworms are examples of parasites that can be transmitted through contaminated food or water. **Chemical Hazards:** Chemical contaminants: Pesticides, herbicides, and other agricultural chemicals can be present in or on food if not properly monitored. Food additives: While many food additives are safe, improper use or contamination can pose risks. Examples include artificial colors, preservatives, and flavor enhancers. Toxins: Some naturally occurring substances, such as mycotoxins (produced by fungi), marine toxins, and plant toxins, can contaminate food. The examples of the chemicals hazards are indicated. **Physical Hazards:** Physical hazards include a variety of materials often referred to as extraneous materials. It may be defined as any foreign material not normally found in a food, which may cause illness or injury to the individuals consuming/using the product. They may cause injury, illness and others may never be noticed. Foreign objects: Physical contaminants like glass, metal, plastic, or wood can accidentally get into food during processing, handling, or packaging. Allergens: Ingredients that can cause allergic reactions in some individuals (e.g., nuts, shellfish, gluten) need to be clearly labeled to prevent unintentional exposure. Few of visible physical hazards are highlighted in Table 2.1  **Allergenic Hazards:** Certain foods and food ingredients can cause allergic reactions in susceptible individuals. Cross-contamination and mislabeling are common causes of allergen-related incidents. Food allergy symptoms include: wheezing or breathing problems, stomach cramps, vomiting, diarrhea, hives, rashes or eczema, whereas, severe allergic reactions can cause death. **A food allergy occurs when the immune system:** - Identifies a particular food protein as danegerous and create antibodies against it. - The next time the individual eats that food, immune system tries to protect the body against the danger by releasing massive amount of chemicals including Histamine. - Histamine is a powerful chemical that can cause a reaction in the respiratory system, gasterointestinal tract, skin or cardiovascular system. - In the most extreme cases, food allergy can be fatal. Although any food can provoke an immune response in allergic individuals, a few foods are responsible for the majority of food allergies. **Radiological Hazards:** Contamination with radioactive substances can occur, especially in certain types of fish or in areas with nuclear incidents. Preventing and managing food hazards involve implementing good manufacturing practices (GMP), Hazard Analysis and Critical Control Points (HACCP), and other food safety management systems. Regular inspections, testing, and proper labeling are also essential components of ensuring food safety. Consumers can contribute to their safety by practicing proper food handling, cooking, and storage at home. Public health agencies and regulatory bodies play a crucial role in monitoring and enforcing food safety standards to protect the public. **Food additives** Food additives are substances added to food products during processing or preparation to enhance their quality, appearance, taste, texture, or shelf life. These additives serve various purposes and are categorized based on their functions. Here are some common types of food additives: **Preservatives:** These additives help prevent spoilage and extend the shelf life of food by inhibiting the growth of bacteria, molds, and yeasts. Examples include sodium benzoate, potassium sorbate, and nitrites. **Antioxidants:** Antioxidants are added to food to prevent or slow down the oxidation process, which can lead to rancidity and color changes. Common antioxidants include vitamin C (ascorbic acid) and vitamin E (tocopherols). **Colorings:** Food colorings are used to enhance or restore the color of food products. They can be natural, derived from plants and minerals, or synthetic. Examples include beet juice (natural) and tartrazine (synthetic). **Flavorings:** Flavor enhancers are added to food to improve or modify its taste. These can be natural, such as herbs and spices, or synthetic, like monosodium glutamate (MSG). **Emulsifiers:** Emulsifying agents help mix substances that would normally separate, such as oil and water. Common emulsifiers include lecithin and mono- and diglycerides. **Stabilizers and Thickeners:** These additives help maintain the texture and consistency of food products. Examples include agar-agar, carrageenan, and xanthan gum. **Sweeteners:** Sweeteners are used to add sweetness to food and beverages. They can be natural, like honey and maple syrup, or artificial, such as aspartame and saccharin. **Acidity Regulators:** These additives control the acidity or alkalinity of food products. Citric acid and sodium bicarbonate are examples of acidity regulators. **Anti-caking Agents:** Anti-caking agents prevent the formation of lumps or clumps in powdered or granulated substances. Silicon dioxide and calcium silicate are common anti-caking agents. It\'s important to note that food additives undergo strict safety evaluations before being approved for use in food products. Regulatory agencies, such as the Food and Drug Administration (FDA) in the United States and the European Food Safety Authority (EFSA) in Europe, set guidelines and maximum allowable levels for these additives to ensure consumer safety. **Food allergens** Food allergy is an abnormal response to a food triggered by the body's immune system. Allergic reactions to food can cause serious illness or even death. Food allergens are proteins within the food that enter our bloodstream after the food is digested. Food allergen go to target organs such as skin, nose, etc and cause allergic reactions. An allergic reaction to food can take place within few minutes to an hour Food intolerance - An abnormal physiological response to eating - Food intolerance is caused by the lack of our body's ability to digest certain substances. - Some people may have a food intolerance that has a psychological trigger. Food allergy is different with food intolerance although both can show similar symptoms. **Types of food allergies** **IgE mediated food allergy** - Reactions occur when allergens bind to Immunoglobulin E (IgE) antibodies bound to mast cells, resulting in the release of histamine and other inflammatory mediators. - Symptoms are usually of rapid onset (\ - FSSAI-CHIFSS is a project between the FSSAI and the CII-HUL Initiative on Food Safety Sciences to foster food safety partnerships between industry, science, and academics. **FSSAI guidelines to limit trans-fat in food items** - India joins a group of roughly 40 countries around the world that have already implemented best-practice policies to remove trans fats and would be one of the first Asian countries to do so after Thailand. - Industrial trans fatty acids are defined as: "All geometrical isomers of mono-unsaturated and polyunsaturated fatty acids with non-conjugated carbon-carbon double bonds in the trans configuration, interrupted by at least one methylene group. - By January 2021, industrial TFA (trans fatty acids) in all fats and oils must be no more than 3%, and no more than 2% by January 2022. - According to the Food Safety and Standards (Prohibition and Restrictions on Sales) Second Amendment Regulations, 2021. On and after January 1, 2022, all food products that contain edible oils and fats as an ingredient must not contain industrial trans fatty acids in excess of 2% by mass of the total oils/fats present in the product - Trans-fatty acids are prohibited in dairy, meat, fish, and their products. **State Food Safety Index (SFSI)** The State Food Safety Index (SFSI), was developed in 2018 in collaboration with the FSSAI. The SFSI was created to motivate the States and Union Territories to improve their performance and work towards establishing an appropriate food safety ecosystem. **Internationally recognized food safety organizations and certification programs include:\ ** **IFS Food 6.1** -- The [*IFS Food Standard*](https://www.ifs-certification.com/index.php/en/standards/251-ifs-food-en) is part of the *Global Food Safety Initiative* and is an international standard for performing audits of food manufacturing processes. Their compliance audits concern both the factory floor and administrative duties, with regulations on topics ranging from the installation of food defense and inspection equipment to thorough bookkeeping.    **BRCGS --** The [*British Retail Consortium Global Standards*](https://www.brcgs.com/) (formerly BRC) are a set of international consumer protection certifications that provide safety criteria for global food retailers, food manufacturers, packaging manufacturers, and food service organizations. Their certification for food manufacturers includes an assessment of the equipment used to detect and remove physical contaminants.   **SQF** -- The [*Safe Quality Food Institute*](https://www.sqfi.com/what-is-the-sqf-program/sqf-food-safety-program/) provides detailed safety programs tailored to the specific concerns of different food industry players. The various SQF codes are segmented to address the unique conditions of each stage of the food production life cycle, from agriculture to packaging, from manufacturing to retail. Each SQF program is internationally recognized.  Each of these private food safety organizations have built their certification programs around ISO 22000, an international norm for food safety management systems: **ISO 22000 --** The [*International Organization for Standardization*](https://www.iso.org/standard/35466.html) details a proactive management plan for food safety relevant for any organization along the food supply chain. ISO 22000 includes an interactive communication strategy between upstream and downstream industry players and a comprehensive system for management. Furthermore, the norm encompasses a model for how to implement a customized HACCP concept depending on the industry, product, and facilities. For instance, should a risk of metal contamination be identified, ISO 22000 may recommend the installation of a metal detector with a rejection mechanism to manage the hazard. **Food Safety Regulation In India** At present in India, the Centre and State Governments are responsible for food safety regulations and the specialised organisations have obligation for effective implementation of these regulations. The following laws and regulations are responsible for food safety \(a) Food Safety and Standards Act, 2006; \(b) Fruit Products Order, 1955; \(c) Meat Food Products Order, 1973; \(d) Edible Oils Packaging (Regulation) Order, 1998; \(e) Solvent Extracted Oil, De-Oiled Meal and Edible Flour (Control) Order, 1967; \(f) Milk and Milk Products Order, 1992; and \(g) Vegetable Oil Products (Regulation) Order, 1998. At the central level Ministry of Agriculture, Ministry of Food Processing Industry, Ministry of Health and Family Welfare, Ministry of Commerce and Food Safety Departments of the respective State Governments are responsible for implementation of these legislations. The function of these governmental agencies include: \(a) review of existing standards; \(b) finalisation of standards; \(c) identification of area where there is requirement of applying new standards; and \(d) formation of standards relating to chemical content, contaminant levels and additive levels in food. Till 2006, the Prevention of Food Adulteration Act, 1954 was the basic food safety legislation responsible for preventing food adulteration. Under this Act, the Central Committee for Food Standards (CCFS) was responsible for formulation of commodity and product standards as well as for determining limits for food contaminants. The Central Food Laboratory (CFL) was responsible for analysing food samples and approval of standardising methods of analysis. The Prevention of Food Adulteration Act, 1954 was also implemented in states through inspectors who operated at the market level and also during transportation and distribution of food items. They had authority to make inspections and collect samples in accordance with prescribed regulations and submit them for analysis. The cases were filed before the magistrate and the penalty for violating the provisions of the Act varied from a fine of Rs 5,000 to a maximum of lifetime imprisonment. The Food Safety and Standards Act, 2006 was enacted as presence of multiple regulatory agencies was hampering effective implementation of regulations governing food safety.\ The Food Safety and Standards Act, 2006 consolidated all existing laws governing food safety. The aim of this legislation is to provide a single reference point for all kinds of food safety standards in India. The Food Safety and Standards Authority of India (FSSAI) established under this Act, is responsible to set standards regulating manufacturing, storage, distribution, sale and import of food products in order to ensure safe food for human consumption. In 2015, the FSSAI issued an advisory that the Blue Bell Creameries ice cream is injurious to health as it contains bacterium Listeriamonocytogenes which weakness the immune system. Similarly, it recommended that the use of potassium bromate should be discouraged in bakeries as it causes cancer. Recently, it has issued an advisory that packing warm food in newspaper exposes the human body to various health problems as printing ink contains cancer causing agents. The Act has defined the word 'food' in a wider sense as any substance whether processed, partially processed or unprocessed which is intended for human consumption and includes primary food as well. The Act has made it mandatory to have a licence for carrying any type of food business and has also insisted for labelling requirements for packed food items where manufactures name, manufacturing date, expiry date and nature of product is to be specified. The Food Safety and Standards Act, 2006 has been an important step for streamlining food safety regulations.\ The Export Inspection Council (EIC) established as the official pre-shipment and certification body under Export Quality Control and Inspection Act, 1963 is responsible for the pre-shipment inspection and certification of consignments which are meant for export. The EIC provides Food Safety Management Systems (FSMS) based certification on the basis of international standards on Hazard Analysis Critical Control Point (HACCP) and Good Management Practice (GMP) for ensuring quality in food processing. The Food Safety Management System certification is mandatory for marine products, egg based products and dairy products. The Marine Products Exports Development Authority (MPEDA) was established to promote the implementation of HACCP system in seafood processing plants. It has encouraged seafood exports by focusing primarily on five areas namely fisheries, aquaculture, processing infrastructure and value addition, market\ promotion and quality control.\ The present framework of food safety regulation is based on scientific and technically improved testing and certification procedures and is supported by the relevant standardising agencies for formulation and imposition of standards. The challenge of implementation of these regulations still persists, mostly with respect to un-organised sector which can further be acknowledged by improving execution of food safety laws and by sensitising general public regarding issues involving food\ safety. **The Role of Food Preservation in Food Safety** Food preservation plays a crucial role in ensuring food safety by preventing the growth of microorganisms, slowing down chemical reactions, and inhibiting the activity of enzymes that can lead to spoilage. The primary goal of food preservation is to extend the shelf life of food products while maintaining their nutritional value, flavor, and quality. Food preservatives play a vital role in preventing deterioration of food, protecting against spoilage from mold, yeast, life-threatening botulism and other organisms that can cause food poisoning. By extension, preservatives reduce food cost, improve convenience, lengthen shelf life and reduce food waste. There are two modes of preservation: physical and chemical. Physical preservation refers to processes such as refrigeration or drying. Chemical preservation is adding ingredients to a food for the purpose of preventing potential damage from oxidation, rancidity, microbial growth or other undesirable changes --- and is considered a "direct additive." The U.S. Food and Drug Administration classifies both natural preservatives (for example, from lemon juice, salt and sugar) and artificial preservatives as "chemical preservatives." While many common preservatives occur naturally, manufacturers often use synthetic versions of these chemicals. Artificial preservatives can be divided into three major groups: The following key aspects provides how food preservation contributes to food safety: **Microbial Control:** **Pathogen Inhibition**: Preservation methods such as canning, pasteurization, and irradiation help eliminate or reduce harmful bacteria, viruses, and parasites that can cause foodborne illnesses. **Spoilage Prevention:** By inhibiting the growth of spoilage microorganisms like mold and yeast, food preservation methods help prevent the deterioration of food quality. **Enzyme Inactivation:** **Enzymatic Browning:** Some preservation techniques, like blanching and dehydration, help inactivating enzymes responsible for browning reactions in fruits and vegetables, preserving their color and appearance. **Chemical Reactions:** Oxidation Control: Preservation methods, such as vacuum packaging and the use of antioxidants, help control oxidative reactions that can lead to the development of off-flavors and deterioration of nutritional quality. Antioxidants are preservatives help to prevent the oxidation of fats and oils, which can lead to rancidity and spoilage. Some common antioxidants include Vitamin C (ascorbic acid), Vitamin E (alphatocopherol), and BHA (butylated hydroxyanisole). Acidulants are preservatives help to lower the pH of food, making it more acidic and less hospitable to bacteria and other microorganisms. Common acidulates include citric acid, lactic acid, and acetic acid Chelation agents are preservatives help to prevent the oxidation of food by binding to metal ions. They are often used in combination with antioxidants. Some common chelation agents include EDTA (ethylenediaminetetraacetic acid) and citric acid. Food preservation is a crucial aspect of maintaining a healthy and safe food supply. **Water Activity Control:** Drying: Removing water from food through methods like drying or dehydration inhibits the growth of spoilage microorganisms since many bacteria and fungi require water to thrive. **Temperature Control:** Refrigeration and Freezing: Keeping food at low temperatures slows down the growth of bacteria and prevents the activity of enzymes, reducing the risk of spoilage and microbial contamination. **Packaging:** Barrier Properties: Proper packaging, including vacuum sealing and gas flushing, creates a barrier against external contaminants, such as air and microorganisms, reducing the risk of spoilage and ensuring food safety. **Fermentation:** Probiotics: Fermentation not only preserves food but also promotes the growth of beneficial microorganisms, such as probiotics, which can contribute to gut health and enhance overall food safety. **Preservation of Nutrients:** Freeze-Drying: This method preserves the nutritional content of food by removing moisture at low temperatures, minimizing the loss of heat-sensitive vitamins and nutrients. **Economic Benefits:** Reducing Food Waste: Food preservation helps extend the shelf life of perishable goods, reducing the amount of food wasted and contributing to sustainable practices. **Regulations and Guidelines:** The FDA has jurisdiction over all preservatives, with the Food Safety and Inspection Service sharing responsibility for the safety of food additives used in meat, poultry and egg products. The FDA mandates that preservatives not be used in such a way as to conceal damage or inferiority, make the food appear better than it is or adversely affect the nutritive value of the food. Food additives approved for use as preservatives are listed in the U.S. Code of Federal Regulations. **Safety** According to the regulatory authorities, preservatives are generally recognized as safe, or GRAS, in the quantities in which they are allowed in individual food products. "Safe" for food additives is defined to mean "a reasonable certainty in the minds of competent scientists that the substance is not harmful under the intended conditions of use." Still, there are some preservatives of concern. Sodium nitrite/nitrate used in processed meats is an example of compounds that may increase the potential of these foods to cause cancer. Studies have linked eating large amounts of processed meats with an increased risk of colorectal cancer. Sodium benzoate and sulfites appear to be safe for most people, but may cause adverse reactions in others. A 2007 study published in The Lancet suggests sodium benzoate and artificial food colorings may exacerbate hyperactivity in young children. Although butylated hydroxyanisole, or BHA, is listed by the National Toxicology Program as "reasonably anticipated to be a human carcinogen," the FDA considers it a GRAS substance in minute quantities. Meanwhile, butylated hydroxytoulene, or BHT, has been banned in some countries but has not been shown conclusively to be carcinogenic. In summary, food preservation techniques are essential for maintaining the safety and quality of food products by controlling microbial growth, inhibiting enzymatic reactions, and preventing chemical deterioration. These methods contribute to the overall goal of providing consumers with safe, nutritious, and flavorful food options. There are different ways to preserve food. Some are ancient methods that have been practiced for generations, such as **curing, smoking, pickling, salting, fermenting, canning, and preserving** fruit in the form of jam. Others include the use of modern techniques and technology, including **drying, vacuum packing, pasteurization, and freezing and refrigeration**. Preservation guards against foodborne illnesses, and also protects the flavor, color, moisture content, or nutritive value of food. **Methods of Food Preservation**  Food preservation methods can be classified as follows ** I. Physical Methods**  A. Preservation by low temperatures 1\. Refrigeration 2\. Freezing  B. Preservation by high temperature 1\. Pasteurization 2\. Canning  C. Preservation by drying 1\. Sun drying 2**. Drying by mechanical driers** ·        Spray drying ·        Foam mat drying ·        Drying by osmosis ·        Freeze drying  D. Preservation by irradiation ** II. Chemical Methods**  A. High concentration of salt B. High concentration of sugar C. Using chemical preservatives ** III. Fermentation** **Preservation OF food** ** 1. Physical Methods** ** A. Preservation by Low Temperatures**  **1. Refrigeration: **The temperature maintained in the refrigerator is 0 to 5°C. Enzymatic and microbial changes in foods are slowed down considerably. Perishable foods like eggs, dairy products, meat, sea foods, fruits and vegetables are stored in refrigerators. Food can be stored safely for few days or a week. ** 2. Freezing: **The temperature of freezer** **is --18 to --40°C. Microbial growth is prevented completely and the action of food enzymes greatly reduced. Frozen foods have better quality and needs uninterrupted supply of electricity while storing. Foods like poultry, meat, fish, peas, vegetables, juice concentrates can be preserved for several months by this method. In vegetables, enzyme action may still produce undesirable effects on flavour and texture during freezing. Various methods of freezing include slow freezing, quick freezing, cryogenic freezing and dehydro freezing. Quick freezing is an ideal method of preserving nearly all baked products. Bread frozen at --22oC or below retains its freshness for many months. Cakes, cookies, short cakes, waffles and pancakes are also frozen and marketed frozen. Many food products can have their shelf-life extended by storing them at 4°C or below. Fresh fruits and vegetables, eggs, dairy products, and meats are all commonly refrigerated foods. However, some items, such as tropical fruits (bananas, for example), are destroyed by low temperatures. Freezing is an excellent way to preserve the nutritional value of foods. It\'s done at a temperature of --18°C to --4°C. The majority of juices are kept by freezing. **B. Preservation by High Temperature**   Food commodities in which pasteurization is employed include milk, beer, wines and fruit juices. 1. **Pasteurization: ** It is defined as heat treatment of food material at 72°C for 15 seconds, 63°C for 30 minutes, or 90°C for 0.5 seconds, followed by quick cooling to 7°C. High-temperature-short-time (HTST) treatments are favoured over low-temperature-long-time (LTLT) treatments because they cause less damage to the nutrient composition and sensory properties of meals. There are three methods of pasteurization.  **a.  Bottle or Holding Pasteurization: **This method is commonly used for the preservation of fruit juices. The extracted juice is strained and filled in bottles. The bottles are then sealed air tight and pasteurized.  **b. Over Flow Method: **Juice is heated** **to a temperature about 2.5oC higher than the pasteurization temperature and filled in hot sterilized bottles. The sealed bottles are sterilized at a temperature 2.5oC lower than filling sealing temperature and then cooled.  **c.  Flash Pasteurization: **The juice is** **heated rapidly to a temperature of about 5.5oC higher than the pasteurization temperature and kept at this temperature for about a minute. This method has been developed specially for canning of natural orange juice, grape and apple juice. It has the advantages of minimizing the flavor loss and preserving the vitamins. **2. Canning: **Canning is the process in which** **the foods are heated in hermetically sealed (airtight) jars or cans to a temperature that destroys microorganisms and inactivates enzymes that can cause food spoilage. The general steps to be adopted for canning foods are cleaning, blanching, filling, exhausting, sealing, sterilizing, cooling and labeling.  **i. Cleaning: **It is the first step in canning.** **Thorough cleaning of the product to be canned helps to remove most of the spoilage organisms. **ii. Blanching: **This process serves as** **an additional hot water wash. It inactivates the food enzymes and fixes the natural colour of the product. It also softens the fibrous plant tissues and facilitates removal of skin. In this process the raw food material is immersed in hot water or exposed to live steam for 2--5 minutes and immediately dipped into cold water to prevent further exposure to heat. **iii. Filling: **Either manually or by using** **machinery the contents can be filled in the cans. A headspace of 6-- 9mm depth above the level of food in the can must be left. **iv. Exhausting: **Gases are expelled by** **passing the open can containing the food through an exhaust box in which hot water or steam is used. It expands the food and expels air and other gases from contents and also from the head space area of the can. **v. Sealing: **The exhausted containers are immediately sealed to avoid re-contamination. **vi. Sterilization: **To bring about complete sterilization, thermal process is carried out. This ensures the destruction of spoilage microorganisms. This is usually done by the application of steam under pressure. **vii. Cooling: **The containers are cooled** **rapidly to check the action of heat and prevent unnecessary softening of the food or change in the colour of the contents. It can be done by means of air or water. **viii. Labelling: **The containers are labelled** **with nutritional characteristics of the food inside. ** C. Preservation by Drying**  Microorganisms need moisture to grow. When exposed to sunlight or subjected to dehydration, the moisture in the food is removed and the concentration of water is brought below a certain level. This prevents the growth of microorganisms and thereby spoilage of food. Food preservation by drying is one of the oldest meth-ods practiced from ancient times. This method consists of exposing food to sun-light and air until the product is dry. It is a very useful and economical process. Both the terms 'drying' and 'dehydration' mean the removal of water. Drying is used to remove moisture by the application of unconventional energy sources like sun and wind. Dehydration means the process of removal of moisture by the application of artificial heat under controlled conditions of temperature, humidity and air flow. ** Treatment of Foods Before Drying**  a.     Selection and sorting for size, maturity and wholesomeness b.     Washing, especially fruits and vegetables c.      Peeling of fruits and vegetables by hand, machine or knife d.     Subdivision into halves, slices, shreds or cubes e.      Blanching or scalding of vegetables and some fruits like tomatoes and peaches f.       Sulphuring of light coloured fruits and vegetables by exposure to sul-phur-di-oxide gas.   **i. Sun Drying: **It is limited to regions with** **hot climates and dry atmosphere and to certain fruits such as raisins, prunes, figs, apricots, pears and peaches. It is a slow process. Many Indian foods are preserved by sun drying. Papads, vadams­ and vathals are made using this principle.  Vegetables like sundaikai, cluster beans, bitter gourd and green chillies are preserved by this method. Fish and meat are also sun dried. The common dried fish or karuvadu (local name) is a good example for sun drying. ** ii. Drying by Mechanical Driers: **Artificial** **drying involves the passage of hot air with controlled relative humidity over the food to be dried or the passage of the food through such air. Fruits, vegetables, nuts, fish and meat can be successfully preserved by this method. In the dehydration process, artificial drying methods like spray drying, vacuum drying, drum drying and freeze drying are used for drying foods.  Although it is expensive when compared to natural sun-drying process, it is very hygienic, rapid and the products obtained are uniform in colour because the temperature and relative humidity can be maintained. ** i. Spray drying**: Milk and eggs are dried to a powder in spray driers in which the liquid is atomized and sprayed into hot air steam or almost instant ­drying. **ii. Foam mat drying:** Foam mat drying may be used commercially to preserve orange and tomato juice. In this pro-cess a small amount of edible foam stabilizer is used. The foam is spread in a thin layer and dried in a steam of hot air. The product gets separated easily into small particles on cooling. **iii. Drying by osmosis:** Drying by osmo-sis results when fish is heavily salted. In this case, the moisture is drawn out from all the cell tissues. The water is then bound with the solute making it unavailable to the microorganisms. In osmotic dehydration of fruits, the method involves the partial dehydration of fruits by osmosis in a concentrated sugar solution or syrup. **iv. Freeze drying:** Removal of water from a frozen product by sublimation is called freeze drying. Freeze dried foods will be of superior quality with light and porous texture. **D. Preservation by Irradiation**   Food irradiation also known as cold sterilization is another preservation technique. The foods are bombarded by high energy rays called gamma rays or by fast moving electrons to kill bacteria, fungi and insects and in some cases to delay fruit ripening or prevent sprouting in onions and potatoes. The goal of irradiation is to kill the microorganisms and inactivate the enzymes without altering the food. **2. Chemical Methods** ** A. Salt or Brine**  It is an ancient preservation technique. Food is treated with salt or strong salt solution. Salt causes high osmotic pressure and shrinking of cell, dehydrates foods and microbes by drawing out moisture.  **B. High Concentration of Sugar**  Sugar has the ability to bind water and make it unavailable for microbial growth. It reduces the solubility of oxygen in moisture, which is essential for the growth and multiplication of microorganisms. Apples, oranges, guavas, grapes and pineapples are suitable for making jams and jellies. The fruits should be just ripe because the pectin content is high in such fruits. **C. Using chemical preservatives**  The chemicals when added interfere with the cell membrane of the microorganisms, their enzyme activity or their genetic mechanisms. They also act as antioxidants. The common chemical preservatives permitted are  1. Benzoic acid (including benzoates) Sodium benzoate is a salt of benzoic acid and is used in preservation of coloured fruit juices and squashes. 2\. Sulphur dioxide (including sulphites): Potassium meta-bi­-sulphite is used as a source of sulphur dioxide when it is added to the juice or squash. When used in fruits with deep colours like blue grapes, jamun, watermelon it bleaches the colour and hence in such cases benzoic acid is desirable. 3\. Organic acids and their salts: Foods can be preserved by adding lactic, acetic, propionic, citric acids and their salts. Nitrates and nitrite compounds are used to preserve meat and fish prod-ucts. It gives desirable colour, flavor and discourages the growth of micro-organ-isms. It also prevents toxin formation by the microorganisms in food. **Salting and Pickling** Salting Salt is added to enhance taste and extend shelf life in foods such as butter, cheese, vegetables, bread and meat products. Dry salting is used for meat, mango, amla and fish.  **Pickling** It is also an ancient preservation technique. The preservation of fruits and vegetables using common salt, vinegar, oil and spices are referred to as pickling. The layer of oil that floats on the top of pickles prevents the entry and growth of microorganisms­ like moulds and yeast. Spices like turmeric, pepper, chilli ­powder and asafoetida retard the growth of ­bacteria. Vinegar provides an unfavorable acidic environment for microbial growth. The salt added absorbs water and prevents the growth of micro-organisms. **Fermentation** Fermentation is one of the age-old methods of food preservation techniques. Fermentation is a metabolic process in which substances undergo decaying in presence of microorganisms to produce desired compounds that can be utilized for improving food quality and safety. Preservation of food by the fermentation process is a great method to preserve foodstuffs even in industrial level. Fermentation not just prolong the shelf life of food but also has many added advantages like it improves the sensory properties of food and even improves the nutritional value of that food itemFermentation means the process of the reaction between microorganisms and organic compounds in natural conditions. Apart from carbohydrate, microorganisms and enzymes react on protein and fat by releasing carbon-di-oxide and other gases. Fermented foods can be defined as the food which has been subjected to desirable physical and biological changes by the action of microbes (yeast, molds, etc) or enzymes that provides the food with significant modification of the food as a whole **Sterilization** Microbes are completely eliminated during sterilisation. Fruits and acidic vegetables, such as tomatoes, can be sterilised at 100°C for 30 minutes; however, non-acidic veggies must be sterilised at 116°C for 30 minutes. ### ** Smoking process** ### Smoking is one of the oldest of food preservation methods. The smoking process allows cured meats, poultry, game and seafood to be subjected to smoke in a controlled environment. The smoke is produced by smoldering hardwood chips, vines, herbs, fruit skins, or spices. This smoke influences the flavor, aroma, texture, appearance and shelf life of foods. **Dehydration** Dehydration is the process of removing moisture from food materials in order to preserve them. The temperature of dehydration starts at 43°C and gradually rises to 60--66°C (for vegetables) and 66--71°C (for meat) (for fruits). **Curing process** Curing may be defined as the addition of salt (Sodium chloride), sugar and nitrate or nitrite to the meat, which results in conversion of the meat pigments into the characteristic cured meat pigments imparting the characteristic cured meat colour and production of characteristic meat flavour. The process of meat curing is currently valued as a means of imparting organoleptic qualities to the cured products,  though it originally was introduced as a means of preserving meat. Due to the advent of efficient and widespread refrigeration the need for preserving meat by curing alone has reduced. Apart from chacteristic colour and flavour, the meat packing industry is concerned with the following attributes also:   - Preservation, - Tenderness and - Yield. **Curing Ingredients** - Sodium chloride - Sodium or potassium nitrate - Sodium nitrite  - Monosodium glutamate - Sugar - Acetic acid - Vinegar and - Spices **Action of Curing Ingredients** **Salt** - Salt acts by dehydration and alteration of osmotic pressure so that it inhibits bacterial growth and subsequent spoilage. - It ionizes to yield the chlorine, which is harmful to the organisms. - It sensitizes the cells against CO~2~. - It interferes with the proteolytic enzyme action. - The effectiveness of sodium chloride varies directly with its concentration and storage temperature. - An acceptable level of salts in hams has been reported to be about 3% and about 2% for bacon. **Sugar** - Sugar softens the products by counteracting the harsh and hardening effects of salt. - It interacts with amino groups of the proteins and upon cooking, forms browning of the products, which enhances the flavour of the cured meats. - Sugar substitutes have been used in bacon cures to prevent excessive browning during cooking. - It acts as a preservative by dehydration. **Nitrates and Nitrites** - Nitrates and nitrites bring about the desired pink colour development -- nitrosyl hemochromes. - Both nitrates and nitrites are used where nitrates act as a reservoir for nitrites. - Nitrate raise the oxidation-reduction potential and therefore are more favourable to aerobic than anaerobic organisms. - They inhibit the growth of food poisoning and spoilage organisms. It has been clearly demonstrated that nitrite is effective in preventing the growth of the *Clostridium botulinum* organism. - They retard the development of rancidity. - Nitrate or nitrite alone or in combination of both shall not be more than 200 ppm in finished products as it is toxic. - The European Directive 95/2/CE (1995) allows 150 ppm of nitrite (if alone) or 300 ppm when combined (nitrite plus Nitrate), and the residual values should be less than 50 ppm (if alone) or 250 ppm (if combined). - There are more stringent limits for curing agents in bacon to reduce the formation of nitrosamines. For this reason, Nitrate is no longer permitted in any bacon (pumped and/or massaged, dry cured, or immersion cured).