Food preservation is a process by which foodstuffs are kept in a way that prevents them from getting spoilt for a long period span. Well-preserved food will retain its nutritive value, color as well as taste. The fundamental reason why food is preserved is connected to the obligatory care of harvest excess and the improvements in the sphere of food transportation and storage. It is important to admit that the presence of molds, bad smell (pungent), spongy growth, fermentation, brown and white spots in vegetables and fruits, and rotting is usually inherent to spoiled grains and food and leads to negative results and products’ damage within a short period (Manas & Pagan, 2005). The presence of microorganisms in foodstuffs such as bacteria, yeast, fungi, and other organisms such as insects, mice, and worms are considered to cause food spoilage. The principle of food preservation entails good methods that considerably slow down or bring to a stop the action of the agents of food spoilage. In addition, the method chosen should not damage the foods. Food is preserved at home using the following methods namely: dehydration, lowering the temperature, increasing temperature, drying, and using natural preservatives such as salt, sugar, lemon, vinegar, oil, and sugar (Lewis, 1989; Nakatani, et al., 1986). The variety of preservation techniques proves that people are interested in products’ safety and abilities to decrease the level of spoilage because there are still several conditions under which food may be spoiled. It is hard to imagine this life without food, to be more exact, without safe food. If a person makes use of food that is not safe and does not take care of conditions under which spoilage takes place, a number of threats to human health appear. People have to preserve food to be safe and promote this safety for a long period of time.
A food preservative is defined as any preservative method or substance that is subjected to food to make it last for a longer duration with a maximum of benefits (Rahman, 2007). As mentioned in the last paragraph, a preservative can be both natural and chemical. Chemical preservatives are either natural or synthetic. However, some common preservatives that are both natural and synthetic include citric acid, benzoic acid, sodium benzoate, parabens, sulfur dioxide, chlorine compounds among others. Among the variety of biochemical aspects, it is necessary to underline the role of sodium nitrite that is characterized as less hygroscopic and more soluble in water (Rahman, 2007)
The Role of Nitrite (NO2–) in Food Preservation
For many years, sodium nitrite has played a major role as the main cure of ingredients used in meat and fish preservation. The reaction involves the production of nitric oxide (NO) and the replacement of oxygen molecules in the meat heme group also referred to as pigment structure. They function to keep meat from turning brown and prevent toxic bacteria that cause food poisoning from developing (Cammack, et al., 1999). The highly reactive nitrite has been observed to retain meat flavor, stability of the microbial, retain color, and act as a potent antioxidant. The work of nitrite is complex enough: within a short period, after it gets the meat, it breaks down into NO and tries to connect to the iron atom that is in meat in order to reduce oxidation. The results of this connection are the changes in meat color when people start cooking.
Sulphur Dioxide as an Integral Part of Food Prevention
Some microorganisms such as bacteria and yeast can ruin a wine so that it is no longer pleasant for consumption. Sulphur dioxide and sorbic acid are commonly used in the wine industry to prevent spoilage and prolong the shelf life of wine. SO2 blocks the growth of bacteria by disrupting the normal functioning of their cell: fermented beverages require a controlling issue that can stop the process if necessary and choose the right direction. SO2 slows down the process of oxidation in wine so that phenol oxidation is stopped and the aldehyde is formed. Sulphur dioxide is an antimicrobial as well as an antioxidant agent. Sulphur dioxide has been used as a wine preservative along with sorbic acid. In addition, SO2 is used in dried fruit, dehydrated vegetables, fruit juice, fruit syrup, as well as pickles (Brul, et al., 2002). Sulfites also have limitations in that they destroy vitamin B1 and have been speculated to cause hyperactivity, and can cause severe reactions in people with asthma (Nguyen-Khoa, 2009). In 1986, many people died as a result of anaphylactic shock which was caused by sulfites on salad. Sulfite was thus banned from use by FDA. However, Food Standards Australia New Zealand (FSANZ) recommended the application of sulfite as food preservatives to meat products at a level up to 500 mg/kg.
Organic Acids as Powerful Preservation Techniques
Organic acids preservatives such as benzoic, sorbic, and propionic acid have been used for many years as food additives. Sorbic acid constitutes a straight-chained monocarboxylic acid with a chemical formula, C6H8O2, however, this very formula is more inherent to the cosmetics industry and personal care products that are acidic or in low acidic media. It was discovered by a German Chemist, Hoffman, in 1939 from un-ripe berries of the rowan or the mountain ash (Tiwari, et al., 2009; Luck, 1990).
Benzoic Acid and Sodium Benzoate. Benzoic acid is an FDA-approved antimicrobial compound available for food preservation. Benzoic acid is found naturally in fruits such as cinnamon, apples, and has antimicrobial properties. Sodium benzoate is much more preferred than benzoic acid due to its high solubility in water. It is effective at low pH below 4.5. The two organic substances, benzoic acid, and sodium benzoate have been used for decades as chemical preservatives for most fruit drinks, soft drinks, and certain foods whose pH are acidic. It is confirmed by FDA both benzoic acid and sodium benzoate have low toxicity in the terrestrial environment (Lado & Yousef, 2002). Sodium benzoate is absorbed by the food cell, and in case pH changes (lower than 5), the process of glucose anaerobic fermentation takes place. In case benzoic acid enters the human organism, it aims at inhibiting the growth of harmful elements like mold, yeast, and other types of bacteria.
Propionic Acid. Propionic acid is used as a mold inhibitor in foodstuffs such as bread, cheese, fresh dough, pudding, jams, and some meat products. It has been commended in the United States as Generally Recognized As Safe (GRAS) substances for food additives. Propionic acid is characterized by a pungent, rancid odor and also it is corrosive and flammable; hence safety measures should be adhered to while handling this acid. The concentration of propionic acid exceeding 1% will inhibit the growth of molds. The recommended level of propionic acid usage ranges from 0.2 to 0.4 % (Hackett & Gutman, 2005). The Federal regulation act has recommended 0.32% as the limit level in bread, flour, and rolls based on the weight of the flour.
The Role of Parabens in Organism. Parabens kill a variety of microorganisms in spite of the fact that they are therefore referred to as a group of broad-spectrum preservatives. Mostly, parabens have been used for years as preservatives to stop harmful microorganisms such as bacteria and yeast in food from growing. Considerable research has been done on parabens for over five decades and concluded as an effective preservative. Though these white powders with limited solubility are not frequently used for food preservation (Russell & Gould, 2003), their possibility to become useful suitable substances seems to be winning. As other significant substances, parables aim at preventing the growth of bacteria and fungi that may be rather harmful to people. There are a number of stuff from food products that are preserved by Parabens: mayonnaise, mustards, jelly, and some soft drinks. As preservatives, parabens have been proven to be safe by FDA as food additives. Parabens have a characteristic of being less sensitizer that enables them to be used in beauty products. Their toxicities are low with low irritating levels. Due to their safe application for the past 5 decades, the United States, Food and Drug Administration (FDA) recommended their use (Benedict, 2006). Further, the Cosmetic Ingredient Review Expert Panel (IREP) recommended their application.
Chlorine Compounds in Food. Some chlorine compounds are used for the disinfection of water as well as an ingredient of food. Such a compound is the disinfectant chlorine dioxide. It has been approved by EPA, FDA, FAO, and the ministry of health from many countries globally (Russell & Gould, 2003). Commanding features of this compound are free activation, not toxic, efficient, and safe to use. It has a unique oxidation feature that enables it to kill various bacteria, fungi, bacteria, and viruses. Stabilized chlorine dioxide is also known as sodium chloride is found in dental care products, and is essential for fighting bacteria in gums. In addition, FDA has approved benzoic salt in food industries as a sanitizer and a preservative to control bacteria and molds.
Important Aspects of Food Preservation
Food contact surfaces in food processing can include all equipment, utensils, and facilities used during processing as well as work clothing and hands and packaging materials. It is therefore important to check routine and chemical tests for the safety of food. This is typically accomplished by sanitizers. Acid sanitizers include acid-anionic, carboxylic acid, and peroxyacetic acid types. Being acids, they remove inorganic soils, such as hard water mineral scale, while sanitizing (Russell & Gould, 2003).
Hydrogen peroxide, octanoic acid, and peroxyoctanoic acid are components of antimicrobial washing treatments recommended by the joint Expert Committee of FAO/WHO for Food Additives. The recommended use of the components, as aqueous antimicrobial treatments, are for spraying, washing, and rinsing, dipping, chilling, and scalding operations of poultry, meat, fruits, and vegetables. Hydrogen peroxide is known to be a very powerful oxidizing agent that is in general effective against a wide broad spectrum that includes microorganisms such as bacteria, yeasts, molds, viruses and spore-forming organisms (Luck, 1985). They are fast-acting even at low temperatures and degrade organic soils to environmentally friendly by-products. In the commercial wash treatments of fruits and vegetables, the octanoic acid component has been claimed as a major antimicrobial agent at target concentrations of 37-180 ppm (Entis, 2002).
Consumers are concerned about additives to their food as evidenced by literature. Processed food contains many chemicals that are added to preserve food, add color, enhance flavour and kill insects, fungi, or bacteria. The United States Food and Drug Administration (F.D.A.) has allowed a wide variety of food preservatives to enter our food supply and at the same time recommended their daily dose (Eichholtz, 1954). However, many health practitioners, nutritionists as well as health-minded consumers tend to avoid preservatives, additives, and other chemical additives because it is not always possible to forecast possible negative consequences and effects on human health after the chosen substance enters the organism.
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