Domain IV Topic B
2.Principles of quantity food preparation and processing
a. Cooking methods
Moist HeatMethod- in which the heat is conducted by dry air, hot metal, radiation, or a minimum amount of fat. Examples: boiling, simmering, stewing, poaching, blanching, braising, and steaming.
Boil-cook in liquid that is boiling rapidly (vegetables and starches) the high temperature toughens the protein of meats, fish, and eggs, and the rapid movement breaks delicate foods
Simmer or Stewing- cook in liquid that is boiling gently ~185 F-205 F
Poach- to cook in a small amount of liquid that is hot but not actually boiling~160 F - 180 F(delicate foods such as fish, eggs, or fruits)
Blanching- cooking an item partially and briefly, usually in water, although some foods, such as fries are blanched in hot fat.
* To dissolve blood, impurities, or salts from certain meats and bones, place the food in cold water, bring to a boil, and simmer briefly, then cool by plunging into cold water.
* To set the color and destroy enzymes in vegetables or to loosen the skin for easier peeling, the food is placed into rapidly boiling water and held there until the water returns to a boil then cooled in cold water.
Braising- cooking foods in small amounts of liquid, usually after browning it (usually meats). Other terms for braising are pot roasting, swissing, or fricasseeing.
Steaming- cooking foods by exposing them directly to steam.
Dry Heat Method-recognize three methods: cooking in oil, cooking in liquids, and cooking in dry heat. In Spears 1999 cooking in oil is considered a dry heat method.
Broiling- involves a heat source above the rack that holds the food (usually meat, poultry, and seafood).
Grilling-cooking over a open grid over a heat source. It may be gas heated, flavored chips, exotic woods, or ceramic briquettes.
Rotisserie-movement of skewers, rotate the food as it cooks, thus driving the natural juices towards the center.
Frying-a tank of oil is heated by gas or electricity into which foods are immersed.
Roasting or Baking-uses a combination of three modes of heat transfers including: conduction, convection, and radiation.
Conduction-is the transfer of heat through direct heat contact of one object or substance with another. Transfer can occur in 3 states of matter: solid, liquid, or vapor.
Convection-the distribution of heat by the movement of liquid or vapor and may be either natural of forced. Natural occurs from density of temperature differences causing hot air to rise and cool air to fall. Forced is caused by a mechanical device such as a fan.
Radiation- pertains to the generation of heat energy by wave action within an object.
b. Equipment
Steam Jacket Kettle- the jacket creates a space surrounding the kettle through which steam is introduced to provide the necessary heat. Most kettles make their own steam and are known as self-contained.
Pressure steamers- traps and removes air causing steam pressure to buildup
Pressureless convection steamer- works by transferring heat to food by using a convection caused by a fan. The fan encircles the food, thus cooking ut without pressure.
Deep fat fryer- oil is heated in a tank powered by gas or electricity.
Ovens:
Range oven- part of the stove that is located under the cooking surface. Primarily used in small services.
Deck ovens- pans of food are usually placed directly on stacked metal decks.
Convection-has a fan on the back wall that creates currents of air within the cooking chamber.
Conveyor oven- (pizza oven) is a conveyorized gas-fired or electric oven that toast the bottom of the food (usually pizza and makes it flaky)
Microwave oven- used more for heating already prepared foods for service than for cooking foods. They are generated by an electromagnetic tube that produces microwaves that penetrate into the foods and agitate water molecules.
Smoker oven- is an electric, compact sized oven with racks to smoke up to 100 pounds of meat at a time. It uses wood chips to produce smoke, and the meat in rubbed with spices and barbeque sauce.
Low-temp cooking and holding oven- has cooking temps from 100 F-325 F and holding temps from 60 F-200 F.
Combi oven- directs the flow of both convected air and steam through the oven cavity to produce a super heated, moist internal atmosphere.
Tilting skillet- a floor mounted rectangular pan with a gas or electric heated flat bottom, pouring lip, and hinge cover. Considered the most versatile of all kitchen equipment. They can cook batches of food.
Convection/microwave oven- a multifunction piece of equipment with convection and microwave capabilities. It can use either function alone or both functions together. It can brown, bake, roast, and steam.
c. Natural and engineered foods (
Genetic engineering is a laboratory technique used by scientists to change the DNA of living organisms.Molecular biologists have discovered many enzymes which change the structure of DNA in living organisms. Some of these enzymes can cut and join strands of DNA. Using such enzymes, scientists learned to cut specific genes from DNA and to build customized DNA using these genes.
Fundamental Weaknesses of the Concept
Imprecise Technology—a genetic engineer moves genes from one organism to another. A gene can be cut precisely from the DNA of an organism, but the insertion into the DNA of the target organism is basically random. As a consequence, there is a risk that it may disrupt the functioning of other genes essential to the life of that organism. (Bergelson 1998)
Side Effects-Scientist do not yet understand living systems completely enough to perform DNA surgery without creating mutations which could be harmful to the environment and our health. They are experimenting with very delicate, yet powerful forces of nature, without full knowledge of the repercussions.
Widespread Crop Failure—Genetic engineers intend to profit by patenting genetically engineered seeds. This means that, when a farmer plants genetically engineered seeds, all the seeds have identical genetic structure. As a result, if a fungus, a virus, or a pest develops which can attack this particular crop, there could be widespread crop failure. (Robinson 1996)
No Long-Term Safety Testing—Genetic engineering uses material from organisms that have never been part of the human food supply to change the fundamental nature of the food we eat. Without long-term testing no one knows if these foods are safe.
Toxins—Genetic engineering can cause unexpected mutations in an organism, which can create new and higher levels of toxins in foods. (Inose 1995, Mayeno 1994)
Allergic Reactions—Genetic engineering can also produce unforeseen and unknown allergens in foods.
Decreased Nutritional Value—transgenic foods may mislead consumers with counterfeit freshness. A luscious-looking, bright red genetically engineered tomato could be several weeks old and of little nutritional worth.
Antibiotic Resistant Bacteria—Genetic engineers use antibiotic-resistance genes to mark genetically engineered cells. This means that genetically engineered crops contain geneswhich confer resistance to antibiotics. These genes may be picked up by bacteria which may infect us.
Problems Cannot Be Traced—without labels, our public health agencies are powerless to trace problems of any kind back to their source.
D.Preservation and Packaging methods
Canning
Canning is the process in which foods are placed in jars or cans and heated to a temperature that destroys microorganisms and inactivates enzymes. This heating and later cooling forms a vacuum seal. The vacuum seal prevents other microorganisms from re-contaminating the food within the jar or can. High-acid foods such as fruits and tomatoes can be processed or "canned" in boiling water, while low-acid vegetables and meats must be processed in a pressure canner at 240 F (10 pounds pressure at sea level).
Pickling-a form of canning with increased acidity which makes it difficult for bacteria to grow.
Jams and Jellies- these have very high sugar content. The sugar binds with the liquid thus making it difficult for microorganisms to grow. To prevent surface contamination after the product is made, jams and jellies are either canned, frozen, or refrigerated.
Drying
This removes most of the moisture from the food. Wiithout moisture the microorganisms cannot grow and the enzyme action is slowed down.
Freezing
Freezingreduces the temperature of the food so that microorganisms cannot grow, yet some may still live. Enzyme activity is slowed down but not stopped during freezing.
Enzymes in Vegetables: These must be inactivated by blanching in order to prevent loss of color, flavor and nutrients. The vegetable is exposed to boiling water or steam for a specified time and then quickly cooled in ice water to prevent cooking. Blanching also helps to destroy microorganisms on the surface of the vegetable.
Unsafe Canning Methods
Open Kettle Method: This is an outdated method of canning that is now considered unsafe. The foods were heated in a kettle and then poured into jars and a lid was placed on the jar. This method often caused spoilage due to bacteria especially botulism.
Steam Canning: Thisis a newer method of canning that is not considered safe at this time. The jars are heated by steam. However, safe processing times have not been developed and steam canners are NOT recommended for either high- or low-acid foods. Low-acid foods canned in these canners are potentially deadly because of possible botulism contamination. Also, both low- and high-acid foods are often very under processed and therefore could spoil.
Other Unsafe Methods: Canning food in the microwave oven, electric ovens, slow cookers or crock pots can be extremely dangerous, especially with low-acid foods, and is not recommended. So-called canning powders are useless as preservatives and do not replace the need for proper heat processing.
Packaging (
Why use packaging?
Packaging provides a physical barrier between a product and the external environment there by ensuring hygiene and reducing the risk of product wastage due to contamination. Some forms of packaging prolong the life of food. Packaging is also needed for safe and efficient transportation. It is also used to provide customers with information and instructions, for which there are some legal requirements.
Packaging materials
Paper: One of the most widely used packaging materials, particularly corrugated cardboard used for transport packaging. The current recycling rate for paper and board packaging waste is 49%.
Glass: is the most common form of packaging waste. Glass can be returned and re-used or recycled easily and a well-established recovery and recycling system exists in the UK. The first bottle-bank in the UK appeared in 1977 and today there are over 20,000. Six billion glass containers are used annually in the UK and the recycling rate is 22%.
Aluminum: is used in many packaging applications such as beverage cans, foils and laminates. It has a high value as a scrap metal with prices ranging from 650-750 pounds per ton and can be recycled economically. Of the estimated 5 billion aluminum cans consumed in the UK in 1996, 31% were recycled.
Steel: is a widely used packaging material for food, paint and beverage as well as aerosols. Recycling steel brings significant resource and energy savings. The current recycling rate for steel cans is 16%.
Plastic: offers several advantages over other packaging materials in its sturdiness and low weight. Even though plastic can be recycled there is a lack of facilities in the UK. The current recycling rate for plastic in the UK is 5%, with the remainder either land filled or incinerated.
Mixed materials: packaging can sometimes have the benefits of being more resource and energy efficient than single material packaging, but combining materials makes recycling difficult. Recycling these materials is hindered by the lack of facilities and technology necessary to separate materials to avoid contamination. Mixed materials packaging can be reprocessed into other products such as floor coverings, shoe soles and car mats, incinerated to produce energy, or land filled.
e. Modified diets
Modified Consistency Diets
Clear Liquid Diet- consists of clear fluids and foods that are liquid at body temperature and leave a minimal amount of residue in the GI tract.
Blenderized Liquid Diet- consists of fluids and foods blended to a liquid form. Mechanically Altered Diet- contains foods modified in texture, such as chopped, ground, mashed, and pureed, to promote ease of mastication. Foods are general moist and require minimal chewing before swallowing.
Dysphagia Diet-refer to the new dysphagia diet guidelines
Therapeutic Diets
Fat-Restricted Diet- generally a diet with <50 g fat (~6 oz {168 g} lean meat or meat substitute and 3-5 fat equivalents per day) or a more restricted diet containing <25 g fat per day (~4 oz {112 g} lean meat or meat substitute and 1 fat equivalent per day).
Indications: fat malabsorption syndromes, Chron’s disease, gastro esophageal reflux disease, chronic cholocystitis.
Fiber-Restricted Diet- indigestible CHO intake is reduced by using limited amounts vegetables and fruit and by replacing whole grain products with refined products. Legumes, nuts, and seeds are omitted.
Indications: ulcerative colitis, Chron’s disease, diverticulitis, stenosis of the esophageal or intestinal lumen.
High-Fiber Diet- a daily dietary fiber intake of 20-35 g is part of a healthy diet. Increased fiber intake should come from a variety of foods and at least 8 -8oz glasses of water should be consumed per day.
Indications: diverticular disease, colon cancer, constipation, Chron’s disease, hypercholesterolemia, obesity.
High-Calorie, High-protein Diet- consists of foods that are calorie dense and protein dense. Generally the diet should consist of 120%-150% of the RDA for energy and protein. Actual amounts will depend on the individual’s height and weight.
Indications: cancer, AIDS, wounds, burns, chronic GI problems, major surgery.
Sodium-controlled Diet: avoid adding salt to diet, avoid foods that have high amounts of sodium.
Indications: hypertension, water retention, some medication use.
Purine-Restricted Diet- Purine occurs primarily in foods of animal origin, with the exception of dairy products and eggs.
Indications: Hyperuricemia, gouty arthritis, uric acid lithiasis.
Tyramine Resrticted Diet- Tyramine is normally found in many foods and the formation of large quantities has been reported in aged, fermented, and spoiled products.
Indications: patients receiving MAOIs.
Gluten Free Diet- avoids products that contain wheat, rye, barley, oats, gluten stabilizers, hydrolyzed or texturized veggie or plant protein.
Indications: gluten-sensitive enteropathy, celiac sprue, celiac disease, nontropical sprue, dermititis herpetiformis.
Lactose-Controlled Diet- avoids products that contain milk solids, whey, curds, skim milk solids, and skim milk powder.
Indications: lactose intolerance, lactose deficiency
4. Distribution
This depends on four factors the type of production system being used, degree of meal preassembly prior to service, physical distance between production and service, and amount of time between completions of production until the time of service.
a. Form of food delivered
- Equipment( last years info has the complete list of pros & cons)
Hot Thermal Retention
- Heat base (pellet unitized base, induction heat based)
- Insulated components-only dinner plate & food heated
- Heat support cart-food is heated until tray is removed from cart
Hot and cold Thermal retention
- Split tray-no assembly of tray required
- Match-a-tray- assembly of meal trays is required
- Insulated trays-maintains hot & cold zones well without external sources
- Insulated components
Cold thermal retention/food reheating
- Refrigerated carts with conduction heat units
- Split-cart refrigerated and convection heat
No thermal Support
- Covered tray-simple and standard