Lecture 01 Nazneen Jahan MIC 302: Food Microbiology

Food Food is any substance consumed to provide nutritional support for the body (to produce energy, maintain life, or stimulate growth). It is usually of plant or animal origin, and contains essential nutrients, such as carbohydrates fats, proteins, vitamins, or minerals

Types of food based on source Almost all foods are of plant or animal origin. Maize, wheat, and rice- in all of their varieties - account for 87% of all grain production worldwide Vegetables Fruits Oils Dairy Meat

Types of food

Types of food based on taste 1. Sweet most pleasant taste, Sweetness is almost always caused by a type of simple sugar such as glucose or fructose, or disaccharides such as sucrose, a molecule combining glucose and fructose 2. Sour Sour is evolutionarily significant as it is a sign for a food that may have gone rancid due to bacteria caused by the taste of acids, such as vinegar in alcoholic beverages

3. Salty Saltiness is the taste of alkali metal ions such as sodium and potassium many different types of salt, with each having a different degree of saltiness, including sea salt, kosher salt, mined salt, and grey salt 3. Bitter Bitterness is a sensation often considered unpleasant characterized by having a sharp, pungent taste Dark, unsweetened chocolate, caffeine, lemon rind, and some types of fruit are known to be bitter

Types of food based on processing 1. Whole food 2. Natural food 3. Organic Food 4. Traditional food 5. Junk food 6. Fermented food

Whole food unprocessed and unrefined, or processed and refined as little as possible, before being consumed. Whole foods typically do not contain added ingredients, such as salt, carbohydrates, or fat Eg: fruits, vegetables and raw dairy products

2.Natural food minimally processed and do not contain any additional agents like sweeteners, food color or flavorings 3.Organic food Does not involve modern synthetic inputs such as synthetic pesticides or chemical fertilizers are not processed using irradiation, industrial solvents, or chemical food additives.

4. Traditional food prepared traditionally that may have a nostalgic or sentimental appeal simply provide an easy-to-eat, easy-to-digest meal rich in calories, nutrients, or both. 5. Junk food have little or no nutritional value considered unhealthy when regularly eaten; all Junk foods are typically ready-to-eat

6. Fermented food Foods or food ingredients that rely on microbial growth as part of their processing or production Highly nutritious Presence of desirable enzymes, pleasing flavor High digestibility Reducing cooking time

The Shelf Life of Different Types of Food Products Factors playing crucial role in determining how long food will stay fresh 1. How it stored at home; 2. the way it has been handled, 3. the way it has been treated and 4. stored before arriving at your local supermarket

Food microbiology Microoranisms in food Food preservation Food borne illness Fermented food

Food associated bacteria Spoilage bacteria :Bacteria that have the capability to produce Food spoilage and subsequently affect fitness for human consumption (availability ). Pathogenic bacteria :bacteria that cause Human illness and/or intoxification and subsequently affect fitness for human consumption (availability ) and result in food borne illness.

Food poisoning Vs spoilage

Food spoilage

Food-borne illness: food poisoning

Food-borne infection

Classical source of foodborne illness The Centers for Disease Control and prevention (CDC) have listed four Classical sources of foodborne illness: disease-causing 1. Bacteria (66%), 2. Viruses (5%), 3. Parasites (4%) and 4. Toxins(25%) At least 30 pathogenic bacteria are commonly associated with foodborne illness

The most emerging bacteria associated with food borne illness The gastrointestinal tract infectious bacteria: Salmonella,Shigella,pathogenic Escherichia coli,Vibrio cholera and parahaemolyticus,Listeria monocytogens,Yersinia enterocolitica and Campylobacter jejuni. The intoxicated bacteria: Staphylococcus aureus,Bacillus cereus,Clostridium botulinum Cl.perfringens

Four factors that contribute most often to outbreaks of foodborne illness are: 1. holding food at the wrong temperature, including inadequate cooling. 2. inadequate cooking. 3. using contaminated equipment when handling food. 4. poor personal hygiene by the food handler.