What are the different heating methods used in food processing?
There are three principal categories of heating methods: pasteurization, extended shelf life (ESL) treatment and ultra-high temperature (UHT) treatment.
How does heat treatment extend the shelf life of food?
All heat treatment extends the shelf life of foods and beverages. Several methods of heat treatment are used to destroy microorganisms like bacteria, spores, yeast, mould and viruses. These methods are mainly distinguished by differences in time and temperature, which are the most crucial factors during heat treatment.
What is the greatest advance in food hygiene?
The greatest advance in food hygiene was inadvertently made when humans discovered the advantage of boiling, roasting, baking and other heat treatments of food, hence preserving the food for longer periods. Food is also rendered safe by the application of heat because most pathogenic microorganisms are comparatively heat-sensitive.
Why is heat treatment of milk and dairy products important?
Most countries employ legislation regulating the heat treatment of milk and dairy products to ensure that the milk products are safe from any pathogenic bacteria. All heat treatment extends the shelf life of foods and beverages. Several methods of heat treatment are used to destroy microorganisms like bacteria, spores, yeast, mould and viruses.
What are the best ways to prevent burns from heat treatment?
The following procedures are suggested for a safe heat treating operation. 1. Wear heat-resistant protective clothing, gloves, safety glasses, and a face shield to prevent exposure to hot oils, which can burn skin. 2.
How hot should a furnace be for heat treating?
Also, preheat the tongs before grasping the heated sample part. 2. Preheat the furnace to 1200 degrees Fahrenheit.
What to do before taking materials out of a liquid carburizing pot?
Before taking materials out of the liquid carburizing pot, make sure that the tongs are not wet and that they are the correct tongs for the job. 9. Make sure that an appropriate fungicide or bacterial inhibitor has been mixed into the quenching liquid. 10. When quench tanks are not being used, always cover them.
What temperature to heat treat steel?
O-1 happens to have a hardening temperature of 1450 – 1500 degrees Fahrenheit.
Does coolant absorb heat?
Coolant will absorb heat given off by the metal as it is cooling, but if there is insufficient coolant, the metal will not cool at the optimal speed. 4. Make sure that there is sufficient ventilation in the quenching areas in order to maintain desired oil mist levels. 5.
Why sterilize food?
Sterilized foods are useful in hospitals for patients with severely impaired immune systems, such as patients with AIDS or undergoing chemotherapy. Foods that are sterilized by irradiation are exposed to substantially higher levels of treatment than those approved for general use.
Who regulates the radiation used to irradiate food?
The Food and Drug Administration (FDA) is responsible for regulating the sources of radiation that are used to irradiate food. The FDA approves a source of radiation for use on foods only after it has determined that irradiating the food is safe.
What is the FDA requirement for irradiated foods?
The FDA requires that irradiated foods bear the international symbol for irradiation. Look for the Radura symbol along with the statement “Treated with radiation” or “Treated by irradiation” on the food label. Bulk foods, such as fruits and vegetables, are required to be individually labeled or to have a label next to the sale container.
Why do we need to store irradiated food?
Irradiated foods need to be stored, handled, and cooked in the same way as non-irradiated foods, because they could still become contaminated with disease-causing organisms after irradiation if the rules of basic food safety are not followed.
How does ionizing radiation affect food?
Food irradiation (the application of ionizing radiation to food) is a technology that improves the safety and extends the shelf life of foods by reducing or eliminating microorganisms and insects. Like pasteurizing milk and canning fruits and vegetables, irradiation can make food safer for the consumer. The Food and Drug Administration (FDA) ...
What is the purpose of irradiating food?
Irradiation can serve many purposes. Prevention of Foodborne Illness – to effectively eliminate organisms that cause foodborne illness, such as Salmonella and Escherichia coli ( E. coli ). Preservation – to destroy or inactivate organisms that cause spoilage and decomposition and extend the shelf life of foods.
What is the purpose of irradiating tropical fruits?
Control of Insects – to destroy insects in or on tropical fruits imported into the United States. Irradiation also decreases the need for other pest-control practices that may harm the fruit. Delay of Sprouting and Ripening – to inhibit sprouting (e.g., potatoes) and delay ripening of fruit to increase longevity.
Why do countries regulate the heat treatment of milk and dairy products?
Most countries employ legislation regulating the heat treatment of milk and dairy products to ensure that the milk products are safe from any pathogenic bacteria.
Why is milk treated with heat?
As with all food products, health and safety are paramount. For reasons of safeguarding public health , the dairy industry treats milk with heat, destroying pathogenic bacteria, which can cause illness in humans. The process has its origins in the 19th century, when milk was a common transmitter of tuberculosis and typhus. French scientist Louis Pasteur (1822 – 1895) discovered that heat treatment kills pathogenic bacteria, as well as bacteria causing spoilage. Since the mid 20th century it has been common practice to pasteurize milk in order to safeguard it for human consumption. Most countries employ legislation regulating the heat treatment of milk and dairy products to ensure that the milk products are safe from any pathogenic bacteria.
How is milk shelf life determined?
The microbiological shelf life of milk is first determined by the number of microorganisms already present in the raw milk. Second, the efficiency in reducing microorganisms by the chosen preservation technique – in this case, heat – determines how many microbes will survive and be present after packaging. Finally, the storage and distribution ...
What is the temperature of milk treated?
High-temperature ESL treatment is performed to destroy all microorganisms that cause spoilage and can multiply during refrigeration. High-temperature treatment (HTT) encompasses heating milk at 120-135°C for 0.5-4 seconds. A common standard of ESL treatment is heating at 127°C for 2 seconds. In Europe, the average shelf life of milk treated at high temperatures is over 30 days.
How long does milk last in a pasteurizer?
Basic standards for pasteurization. Milk is commonly pasteurized in plate heat exchangers at 72-75°C for 15 seconds. This temperature is sufficient to destroy all pathogenic bacteria, while significantly reducing the number of organisms that can cause spoilage.
What is Tetra Pak heat treatment?
There are three principal categories of heating methods: pasteurization, extended shelf life (ESL) treatment and ultra-high temperature (UHT) treatment. Tetra Pak promotes continuous processing with quick heating and cooling, and a precisely calculated holding time, resulting in a much lower heat load applied to the milk compared with traditional batch methods.
Why is milk pasteurized?
Since the mid 20th century it has been common practice to pasteurize milk in order to safeguard it for human consumption. Most countries employ legislation regulating the heat treatment ...
How to prevent food contamination?
There are other general principles for preventing food contamination: 1 All water used in food preparation should be wholesome. 2 All dishes, glasses and utensils must be kept clean by regular washing in clean water, and clean utensils should be kept covered. 3 All surfaces that come into contact with food should be meticulously clean (Figure 10.1). 4 Food storage, preparation and serving areas should be free of pets, rats, mice and insects. 5 Food should be covered, and kept separate from chemicals and poisons (which should be clearly labelled). 6 Cloths that come into contact with dishes and utensils, and that are used to cover food, need to be changed daily and boiled before use.
What is food protection method?
Food protection methods are measures taken to protect food from being contaminated by any agent. All food must be protected at all times during storage and preparation from the following contaminants:
How does freezing preserve food?
Freezing preserves the storage life of foods by slowing down enzyme reactions and the growth of microorganisms.
What is food preservation?
Food preservation includes a variety of techniques that allow food to be kept for extended periods of time without losing nutritional quality and avoiding the growth of unwanted microorganisms. There are three basic objectives for the preservation of foods:
What temperature should food be cooked at?
Food that is to be cooked must be cooked thoroughly to kill all pathogenic microorganisms. All parts of the food must reach a temperature of at least 70 o C. You cannot tell how hot the food is just by looking, so it is important to cook the food for long enough to make sure that it is all cooked through.
How cold should food be stored?
Perishable and potentially hazardous foods that can be easily contaminated, such as milk and raw meat, should be stored at low temperature, preferably in a refrigerator at below 10 º C. Frozen foods should be stored in a freezer below -18 º C.
What are the factors that affect food safety?
flies, rodents and other vermin. insecticides and other chemicals. unclean utensils and work surfaces. cigarette smoke. These factors either affect the food directly to make it unsafe (such as cigarette smoke or soot), or, like coughs and sneezes or insects, contaminate the food with microorganisms.