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Food processing is a science-driven industry that demands extensive knowledge of chemistry, microbiology, and physical properties of various food and agricultural products. This requires engineering skills to enable food processing and packaging equipment.
Traditional food processing methods are still used today
Food processing is one of the oldest industries in the world. For as long as humans have produced food, we have needed ways to process it for optimized nutrition, longer shelf life, and improved taste. Some basic food processing methods can be found anywhere from an open campfire to an industrial-scale processing facility.
• Cooking is the most ubiquitous form of processing. Heat is applied through various methods like baking, grilling, roasting, and frying. All of these processes require materials that can stand up the varying degrees of heat without degrading or releasing toxic material into food.
• Drying is one of the oldest methods for preserving food. While sun-drying has been used for thousands of years, modern plants employ techniques like freeze-drying (see below).
• Smoking is another simple but effective method for preserving a wide variety of foods. Industrial-scale smoking involves massive smoking chambers that can handle large quantities of food at once.
• Fermentation is a chemical process caused by bacteria and other microorganisms like yeasts in anaerobic (no oxygen) environments. In addition to its famous use for alcoholic beverages, fermentation is used to make products like sauerkraut, yogurts, and bread yeast.
• Pickling: this process can refer to either brine or vinegar immersion. The key feature of this process is a pH sufficient to kill most bacteria. In traditional pickling, antimicrobial herbs like mustard seed and garlic can also be added to the mix. Brine also draws out moisture from food, enhancing preservation. Pickling has been in use at least since the Indus Valley civilization around 2400 BC.
• Salting/Curing: this process works similarly to pickle brine, but uses dry salt, typically on meats. Salting was the main method for preserving meats until the advent of refrigeration. Salt draws water out of the meat to dramatically reduce spoilage.
Although these techniques are still used (in highly advanced and scaled-up form) in industrial-scale food processing, today's food processing companies have developed entirely novel processes.
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Advanced food processing methods
Some versions of industrial food processing (such as conveyorized ovens) are simply large-scale versions of traditional food processing techniques. However, the technologies available in industrial-scale food processors have opened up entirely new avenues for food processing.
• Freezing, Flash Freezing, and Freeze Drying: freezing dramatically improves freshness and shelf-life for a huge variety of foods, and techniques like flash-freezing help prep food at mass-production speeds and volumes.
• Irradiation: exposing food to ionizing radiation can improve food safety, delay the sprouting of plant products, and help control insects and other pests.
• Pasteurization: in this technique, invented by Louis Pasteur in 1864, food is rapidly heated and then cooled, a reliable method for killing potentially harmful microorganisms.
• High-Pressure Processing: sometimes called Pascalization, this process processes food in high-pressure conditions which kills many bacteria types, improving safety and shelf life. This process is desirable for its energy efficiency, decreased processing time, and the absence of additives. This relatively new process was invented starting being used commercially in the 1990’s and is still being perfected.
• Extrusion: mixed ingredients are forced through an opening to form a continuous shape that can subsequently be cut into a specific size by a blade. This method allows for efficient mass production of food that can be easily cut to size after it is produced.
• Modified Atmosphere Packaging: air inside a package can be substituted with a special gas mix designed to slow spoilage, extend shelf-life, and improve food safety.
• Chemical Additives: In addition to vitamins, antioxidants help prevent oil from going rancid. Emulsifiers can help products like salad dressing from separating into oil and water in the package.
As is the food processing equipment
All the above processes require special equipment. Depending on how a food product is processed, food needs to be carefully cleaned, prepared, and packaged -- each of these tasks creates a need for more equipment. Below we list just a few of the vast array of highly-specialized equipment used in food processing.
• Cleaning: Sprayers, Ultrasonic Cleaners, Magnetic Separators
• Grading Equipment: lab-like equipment to test food quality.
• Preparation: rollers, peelers (blade/steam/flame), sorting equipment
• Mechanical processing: mills, crushers, strainers, pulpers, slicers, grinders, and saws.
• Extruding Equipment
• Agglomeration Equipment: Pelletizers, Rotating Drums, and High-Speed Agitators
• Forming Equipment: Molders, Formers, and Enrobing Machines
• Mixers: paddle, turbine, anchor, and agitated tank mixers.
Examples and equipment of food packaging The types of packaging used for food are as varied as the food itself. A few prominent examples include trays, bags, cans, coated paper cans, pallets, and plastic wrap. For many food products, each salable item will require multiple packaging techniques, such as frozen foods with a tray, plastic wrap cover, and outer box (and this means multiple packaging machines for just one production line). To package processed foods on an industrial scale, food companies use a variety of specialized equipment. Some important examples include:
• Vacuum-packaging machines remove air from plastic packaging to reduce atmospheric oxygen, limiting microbe growth and evaporation to improve shelf-life.
• Cartoning machines that automatically fold paper cartons, applying adhesive as necessary.
• Coding and labeling machines not only apply repetitive graphics like marketing labels but also autocade information that is essential for tracking food freshness.
• Filling and bottling machines for beverages and other liquid products.
• Capping machines to seal and cap bottled liquids.
A single food manufacturing facility may only need to employ many of the machines highlighted above on a single production line. Food manufacturers face the challenge of keeping all this equipment up and running in a manufacturing environment with some unique challenges. Today there is no substitute for food processing and packaging in food preservation and multiple uses of food.
- SZK based on online information
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