Food Sensory Evaluation & Food Safety 8th Lecture PDF

Food Sensory Evaluation & Food Safety 8th lecture Dr. Mohamed Elsaadany  Outline Sensory evaluation Sensory evaluation techniques Subjective tests Effective (Analytical) Affective Taste Panels Sample Preparation Objective tests Physical testes...

Food Sensory Evaluation & Food Safety 8th lecture Dr. Mohamed Elsaadany  Outline Sensory evaluation Sensory evaluation techniques Subjective tests Effective (Analytical) Affective Taste Panels Sample Preparation Objective tests Physical testes Chemical tests Food safety Foodborne illness Preventing foodborne illness Dr. Mohamed Elsaadany 2  food preparation Introduction Sensory evaluation is a scientific discipline that is used to measure and analyze people's responses to products as perceived through the 5 senses - sight, smell, touch, taste and sound. Wide array of testing methods are used measure the sensory factors related to food selection and to evaluate food quality. Benefits of Sensory evaluation of food: Research and development, product improvement, sales and marketing, quality assurance, nutrient content analysis (Nutrition Facts), and detecting contamination or adulteration. Dr. Mohamed Elsaadany 3  foodtechniques Sensory evaluation processing Sensory evaluation techniques are achieved through Subjective and Objective analysis 1. Subjective analysis Evaluations of food quality based on sensory characteristics and personal preferences. it relies on the opinions of selected individuals. often used by large food companies for the purposes of evaluating consumer preference and/or acceptability for potentially new and/or established products 2. Objective analysis Evaluations of food quality that rely on numbers generated by laboratory instruments that are used to quantify the physical and chemical differences in foods. Dr. Mohamed Elsaadany 4 SUBJECTIVE ANALYSIS Dr. Mohamed Elsaadany 5  Types of subjective analysis Two Types of subjective analysis 1. Analytical (effective) 2. Affective In both subjective test food samples are presented to taste panel participants, who evaluate the foods according to specific standards for appearance, odor, taste, texture, and sound. Dr. Mohamed Elsaadany 6  Types of subjective Testing 1. Analytical (Effective) Tests The more objective analytical tests are usually conducted by a trained panel that evaluates food products through either discriminative (are the samples different?) or descriptive tests (how much do the samples differ?). The most common difference tests are the triangle and duo-trio tests in which the person compares three samples and has to determine if a difference exists 2. Affective Tests These types of tests are usually given to untrained consumers. The test instruments range from simple questions (which of the two samples do you prefer?) to complex 9-point hedonic product score sheets evaluating one or more factors of a food on a scale from “like extremely” to “dislike extremely” Dr. Mohamed Elsaadany 7 Types of Sensory Testing Dr. Mohamed Elsaadany 8  Taste Panels The individuals on a taste panel can range from randomly selected members of the population to experts who are highly trained in tasting a particular food or beverage. The ability to detect slight differences in specific foods is prized so much (the taste buds of one gourmet ice cream taste expert are insured for $1 million). General taste panels usually consist of at least five people who meet the following criteria: they are free of colds, chew no gum immediately before testing, have not ingested any other food for at least 1 hour before testing, are nonsmokers, are not color blind, and have no strong likes or dislikes for the food to be tested. An equal distribution in gender is preferred, because women can usually detect sweetness better than men can Age distribution of the panel is also considered, because it may affect test results. Dr. Mohamed Elsaadany 9  Sample Preparation The environment in which the taste panel evaluates should carefully controlled Panelists may be seated at tables, cubicles or booths, and the food is presented in a uniform fashion. Food samples must be of the same size (enough for two bites), From the same portion of the food (middle vs. outside), Equally fresh, At the same temperature, Presented in containers or plates that are of the same size, shape, and color. White or clear containers are usually chosen The lighting in the room is uniform Dr. Mohamed Elsaadany 10  Sample Preparation Ambient temperature is comfortable and the surroundings quiet and odor free. Mid-mornings or mid-afternoons are considered the best times for sampling, Samples are randomly coded A reasonable number to avoid “taste fatigue.” Room-temperature water or plain bread is made available for panelists to eat between samples to prevent carryover tastes, At least a 30-second rest period is scheduled between samples. Paper towels or napkins are provided, and, because swallowing the food or beverage influences the taste of subsequent samples Small containers into which samples may be spit are provided. Dr. Mohamed Elsaadany 11 OBJECTIVE ANALYSIS 1 Dr. Mohamed Elsaadany  OBJECTIVE EVALUATIONS Food selection criteria In objective evaluations, laboratory instruments instead of humans are used to measure the characteristics of foods quantitatively. Gives more objective data than does sensory testing, and is less costly and time consuming. But they cannot substitute for sensory testing by real human beings, However, human senses cannot detect the quantitative measures determined by physical and chemical tests. These tests analyze for the presence of potentially harmful micoorganisms; create standards for maintaining quality control; and identify almost any chemical in foods used for nutrition fact labeling, moisture content analysis, and detecting the presence of allergens or toxins. The two major types of objective evaluation tests are physical and chemical, Dr. Mohamed Elsaadany 13  OBJECTIVE EVALUATIONS Food selection criteria Physical Tests Physical tests measure certain observable aspects of food such as size, shape, weight, volume, density, moisture, texture, and viscosity Selected laboratory instruments usually purchased by companies that need to ensure that their products meet certain quality control guidelines. Dr. Mohamed Elsaadany 14 15  Chemical Tests Chemical Tests The number of chemical tests available for use on foods is almost limitless Many are based on the work of the Association of Official Analytical Chemists (AOAC) International, which publishes a book on chemical tests, including those for determining various nutrient and nonnutrient substances in foods. Dr. Mohamed Elsaadany 16 1. Sight Sight Dr. Mohamed Elsaadany 17 Food safety 1 Dr. Mohamed Elsaadany  FOODBORNE ILLNESS Odor Symptoms of foodborne illness often include inflammation of the gastrointestinal tract lining, nausea, abdominal cramps, diarrhea, and/or vomiting. The most common causes of foodborne illness are: Biological, Chemical and Physical hazards 1. Biological Microorganisms Bacteria Molds Viruses Animal parasites Prions The most common cause biological foodborne illness is bacteria via: infection or intoxication (poisoning). Food infections, responsible for about 80 percent of foodborne illnesses, occur when a person consumes a food or beverage containing large numbers of bacteria. Food intoxication and toxinmediated infection occur when a person consumes a toxin from bacteria growing on food. Other foodborne illnesses are caused by mycotoxins in molds, viruses such as the hepatitis A virus, parasites, and protein particles called prions, which are responsible for mad cow disease. Dr. Mohamed Elsaadany 19  FOODBORNE ILLNESS Odor 2. Chemicals Plants Seafood toxins Agricultural/industrial Chemicals come from plants such as poisonous mushrooms, fish or shellfish that contain dangerous toxins. histamine etc…and agricultural or industrial chemicals, 3. Physical Foreign objects in food Dr. Mohamed Elsaadany 20  PREVENTING FOODBORNE ILLNESS Taste Personnel Ensure that employees are trained in personal hygiene habits such as avoiding hand to mouth movements, using hand-washing sinks frequently, wearing clean uniforms, and other safe work-related food techniques. Purchasing Vulnerable, high-risk foods prone to microbial contamination are those high in protein and water like meat, poultry, fish, dairy, egg, broth, stocks, sauces, tofu, soy foods, and stuffing. Written specifications and inspections upon delivery by trained personnel help reduce problems. Storage Food should be stored at correct temperatures: (4°C) in the refrigerator -18°C in the freezer, (15–21°C) dry storage for canned goods, and (10–21°C) dry storage for root vegetables, citrus, eggplant, and hard-rind squash. Dr. Mohamed Elsaadany 21 PREVENTING FOODBORNE ILLNESS  PREVENTING FOODBORNE ILLNESS Taste Preparation Pre-Preparation Thawing—The four safe methods for thawing are in the refrigerator, submerged under running water, microwaving followed by cooking, and as part of the cooking process. Cross-contamination—Be sure to avoid having raw, high-risk vulnerable foods come in contact with cooked food or food that will not be cooked. Surfaces (hand, counter, cutting boards) should be carefully monitored. Cooking (Heating) Minimal internal temperatures needed to destroy microorganisms in different foods is important (between 71-74 °C for most poultry and meats and 57°C for most cooked fruit and vegetable Holding and Serving Food must be held and served outside the temperature danger zone, 4°C–60°C for consumers. Above 57°C for hot foods and below 5°C for cold foods. Cooling The four safe methods to cool food are placing in shallow containers, reducing food size, placing in an ice-water bath, and using a blast chiller below 4°C within 4 hours. Two cooling stages: 57°C to 21°C in the first 2 hours, and then to 5°C within 6 hours or less. Dr. Mohamed Elsaadany 23 Taste 24  PREVENTING FOODBORNE ILLNESS Taste Sanitation Regularly scheduled cleaning, safe equipment, and a clean facility are all part of sanitation. Washing Three-compartment sink temperatures should reach 43°C during soaking and at least 82°C for 1 minute during final rinsing. Dishwashing machine temperatures should be between 60°C and 71°C , and rinse temperatures at least 82°C for 10 seconds or 77°C for 30 seconds to kill most pathogens. Drying Only air or heat drying is considered safe. Pest Control Pests should be blocked from entering food establishments, prevented from accessing stored food, and eliminated by a pest control operator Dr. Mohamed Elsaadany 25 THANKS! Any questions? Dr. Mohamed Elsaadany 27