*4.3.5 Chemical preservatives*

Antimicrobial chemical agents are added for the long-term preservation of foods [3]. These chemical agents are added in small quantities, where large amounts can be toxic. For example, acid and benzoates are used for food preservation in acidic foods, such as jams, salad dressings, juices, pickles, carbonated drinks, and soy sauce. Sorbic acids and sorbates are used for cheese, wine, baked foods, and others. In the case of meats, nitrates and nitrites are used to prevent the botulism toxin [3]. For fruits and vegetables, sulfur dioxide and sulfites are used, whereas propionic acid and propionates are used for baked foods.

## *4.3.6 Pascalization*

In this process, the foods are exposed to very high pressure to the tune of high pressure, such as 70,000 lb. per square inch [3]. This process helps to retain the food's flavor, freshness, texture, and nutrients and destroys the microbes. After this treatment, the rate of food spoilage decreases significantly. This technique is mostly used for juices and meats.

#### *4.3.7 Biopreservation*

This process uses natural microbes or antimicrobials for preservation to improve the shelf life of foods [3]. In this process, beneficial bacterial or fermentation products are used to control and inactive the microorganism's growth [3]. Lactic and acetic acid bacteria are used as biopreservatives. These produce lactic acid, acetic acid, bacteriocins, and hydrogen peroxide, which act as antimicrobials and preserve the foods. D'Amico de Alcântara et al. [18] studied the antibacterial activity of *Lactobacillus rhamnosu* against *Pseudomonas fluorescens* and *Pseudomonas putida*, both isolated from refrigerated raw milk. These authors found that the antibacterial activity is due to organic acids produced.

#### *4.3.8 Hurdle technology*

In hurdle technology, more than one approach is used to inactive the microbes. The multiple preservation approaches act as hurdles for microorganisms and prevent their spoilage. Leistner [19] used hurdle technology, combining various hurdles that secure food from spoilage and preserve nutritional quality. Also, the hurdles do not induce smell or change the texture of preserved foods. Some of the hurdle approaches are high temperature, in combination with pressure, acidity, and adding biopreservatives. The selection of hurdles depends on the food's nature and potential pathogens.

#### *4.3.9 Nonthermal plasma*

In this process, the food surface is exposed to a flame of ionized gas molecules, such as nitrogen or helium to kill the microbes on the food's surface [3].

#### *4.3.10 Modified atmosphere*

In this process, the oxygen is reduced, and carbon dioxide is increased in the storage environment. For example, vegetable and fruit salad bags are stored in reduced oxygen and higher carbon dioxide environments [9, 20, 21]. These storage environments can result in the loss of some of the nutrients in the foods. This method is also used for the preservation of grains. The carbon dioxide used helps *Introductory Chapter: Food Processing, Preservation, and Packaging – A Brief Overview DOI: http://dx.doi.org/10.5772/intechopen.110229*

to prevent the growth of insects, molds, and oxidation reactions and prevent grain damage. In the sealed room, the oxygen levels are reduced by infusing nitrogen gas [3]. On average, oxygen is 21% in the air, whereas, in such facilities, the oxygen level is reduced to 1 and 2%. Hermetic storage is an airtight storage widely used for storing grains. This method reduces the grain's respiration and prevents the growth of insects, fungi, and pests [22].

#### **4.4 Benefits of food processing and preservation**

The key reason is to maintain the quality and stability of a product. Fresh juice, for example, will easily phase-separate after extraction, and enzymes start to degrade valuable components, such as antioxidants. If these enzymes are inactivated by pasteurizing (heat-treating) the juice, spoilage can be slowed down [23]. This also applies to products that include a large amount of fat, as they easily become rancid when enzymes are still active and oxygen is present. Processing also makes some foodstuffs more digestible by softening tissue or breaking it down [1].

Furthermore, processing increases the variety of food products available to the consumer and makes them more convenient, meeting the demands of our on-the-go lifestyle. Lastly, food processing is important in ensuring that food is affordable. Furthermore, proper storage of foods, such as fruits, vegetables, and grains, can help reduce the spoilage and waste of foods and solve the food shortage in developing and underdeveloped countries.

Some of the major benefits and drawbacks of food processing and preservation are as follows:

