Food preservatives

Preservatives are a type of food additive added to food to prolong shelf life and keep the products from being broken down by microorganisms (yummy). Mold, bacteria, and yeast can cause food spoilage and are found practically everywhere (including the air we breathe). And these modern additions have certainly made an impact. In fact, some researchers believe preservatives have changed eating habits and food production patterns more than any other type food additive . Before running to the pantry to look at what preservatives are listed on those yummy snack packs, let’s highlight some of the preservatives to keep an eye out for.

Food preservatives are substances ‘that are added to food items in order to inhibit, retard or arrest the process of fermentation, acidification, and decomposition of food items’. Or, in other words, preservatives in food help keep the food safe, without spoiling, for longer.
Food preservatives are classified as:

Class I preservatives or the natural preservatives such as salt, sugar, vinegar, syrup, spices, honey and edible oil; and

Class II preservatives or the chemical preservatives such as benzoates,Sorbic acid Salt, nitrites and nitrates of sodium or potassium, sulfites, glutamates, glycerides and the like.
Both, natural and chemical preservatives are categorized into 3 types:

Antimicrobials that destroy or delay the growth of bacteria, yeast and molds. E.g. nitrites and nitrates prevent botulism in meat products. Sulfur dioxide prevents further degradation in fruits, wine and beer. Benzoates and sorbates are anti-fungals used in jams, salads, cheese and pickles.

Anti-oxidants that slow or stop the breakdown of fats and oils in food that happens in the presence of oxygen(Oxidation) leading to rancidity. Examples of anti-oxidants include BHT, BHA, TBHQ, and propyl gallate.

Anti-enzymatic preservatives that block the enzymatic processes such as ripening occurring in foodstuffs even after harvest. E.g. Erythorbic acid and citric acid stop the action of enzyme phenolase that leads to a brown color on the exposed surface of cut fruits or potato.

Although preservatives can extend the shelf life of food, but most preservatives is harmful to our body, we should try to avoid eating foods containing preservatives.

What’s Sorbic acid?

Sorbic acid, or 2,4-hexadienoic acid, is a natural organic compound used as a food preservative. It has the chemical formula C6H8O2. It is a colourless solid that is slightly soluble in water and sublimes readily. It was first isolated from the unripe berries of the rowan tree (Sorbus aucuparia), hence its name.

Sorbic acid is a natural, organic preservative frequently used to maintain the freshness of a variety of human foods, drugs, and cosmetic products. Potassium sorbate and sorbic acid possess antifungal, and to a lesser extent antibacterial, properties.

Sorbic Acid is derived from the berries of the mountain ash tree, and has traditionally been used as a preservative for food and wine due to its ability to prevent spoilage caused by yeasts, fungis and molds, as well as some other bacterias (Wikipedia). Although it is considered an effective preservative, “Several microorganisms can metabolize sorbic acid particularly when it is present in small concentrations. For this reason, it is not a suitable preservative in foods with high microbial counts,”

Sorbic acid is a preservative found in many foods and skin products. It is considered non-toxic, so you are unlikely to experience problems eating foods containing the chemical. However, you might suffer a sensitivity reaction when substances with sorbic acid come into contact with your skin, eyes or lungs. These reactions are typically minor and not life-threatening.
Sorbic acid and its salts, such as sodium sorbate, potassium sorbate, and calcium sorbate, are antimicrobial agents often used as preservatives in food and drinks to prevent the growth of mold, yeast, and fungi. In general the salts are preferred over the acid form because they are more soluble in water, but it is the acid form that is active. The optimal pH for the antimicrobial activity is below pH 6.5. Sorbates are generally used at concentrations of 0.025% to 0.10%. Adding sorbate salts to food will, however, raise the pH of the food slightly so the pH may need to be adjusted to assure safety. It is found in many other foods, such as cheeses and breads.