Food Perishability and Preservation

Food Perishability and Preservation


Long term exposure of foods to oxygen from air, light, and heat, enable microbial proliferation, and change food ingredients. Such food can be poisonous. The signs of rotten food include:

1. Rancid smell and taste; fats develop a penetrating and unpleasant odor, bitter flavor, and change in color.

2. Rooting food loses its nutrients (essential fatty acids, vitamins).

Antioxidants in Food

Antioxidants, known as oxygen “catchers” prolong the durability of food by protecting it against deterioration caused by oxidation.

Natural Antioxidants protect food against oxidative changes. The best natural antioxidants are in sesame oil, cottonseed oil, and some spices (rosemary, sage).

The protective substances that clean and fight free radicals in our body are vitamin E, vitamin C, carotene, and selenium.

Food Additives

Food additives are substances added to food products during processing, packaging, transport, and storage, in order to extend its durability.

Additives that have been used since ancient times include preservatives and flavorings for better appearance and consistency, both natural and artificial colors, emulsifiers, and more.

With the development of the food industry, from the19th century onwards, there has been a steady increase in the use of chemicals in food production and additives.

Today, each country has its own special regulations regarding additives.

The additives include sugar, salt, and ingredients in order to improve the nutritional value (vitamins, minerals, inulin, etc.).

Additionally, liquid pectin, dextrin, starch, gelatine, casein and other milk protein, gluten, blood plasma, amino acids (except for glutamic acid, cystine, cysteine, and glycine), can all be used as additives.

Additives can be found in almost all kinds of food we consume such as milk and dairy products, chocolate, vegetables, cereals, bakery products, etc.

To Identify additives we use E-numbers that are generally accepted worldwide. The labeling refers to the toxicological evaluation and classification of additives.

 Additive-free food: honey, unprocessed fresh meat, organic vegetables, and fruits. 

Joint Expert Committee on Food Additives put on a positive (additive) list hundreds of different substances! 

They say there is no health risk of use of food additives and that additives do not represent a major threat to human health except for those individuals with specific sensitization.

Side Effects Of Food Preservatives and Additives

Sulfur dioxide (SO2), which has been used for thousands of years in wine production, as a means of preventing the development of undesirable microorganisms, in people sensitive to the sulfite may cause bronchospasm, asthmatic attacks, urticaria, anaphylactic shock, and other serious conditions.

Nitrites and nitrates (NaNO2, KNO2, KNO3) are preservatives in combination with kitchen salt in a certain proportion. They are used for preserving fish and curing. Given the toxicity of nitrite, special attention should be paid to the production, distribution, and control of these additives. Incorrect quantities of nitrite mixture (with salt) can adversely affect health.

Bactericides/Antibiotics: Antibiotic Nisin, effective against gram-positive bacteria (Listeria, etc.) is used for preserving milk, cream, and melted cheese.

Primaricin, an antifungal agent, is used for the crust of cheese and sausages. Experts warn that the overuse of antibiotics in food may lead to antibiotic-resistant bacteria.

Aromas & Enzymes In Food Industry

Aromas (flavors) are substances derived from physical, enzymatic or microbiological processes from plants and/or animal origin, used or intended for use in the manufacture of food products in order to be given a smell or taste. They include flavoring substances, flavoring products, and smoke flavorings and their mixtures. There are natural and artificial flavors, obtained by chemical methods, but chemically identical to natural substances.

Surface Active Agents

  • Thickeners increase food viscosity
  • Stabilizers allow the maintenance of the physical and chemical state of food
  • Emulsifiers enable the establishment or maintenance of a homogeneous mixture of two or more phases that do not interfere, such as oil and water in food
  • Emulsifying salts are substances that allow for homogeneous mixing fats and proteins with other food ingredients
  • Gelling agents are substances that give foods a gel-like consistency
  • Gums
  • Salts
  • Lecithin
  • Starches, etc.

EU regulations prescribe the conditions and maximum permitted levels of these substances that do not represent a risk to human health (its chemical name of the aromatic substances, synonymous title, chemical and structural formula, stability, interaction with food components, etc.).

The prescribed maximum allowed quantities of heavy metals and benzopyrene are as follows:

  • 3 mg/kg of arsenic, 10 mg/kg of lead, 1 mg/kg of cadmium in added flavors
  • 03 g/ kg 3,4-benzopyrene in flavored products and beverages

The following questions still remain unclear:

  1. Do the regulations on labeling of flavorings oblige producers to declare whether it is natural aroma (traditional food preparation methods such as natural lemon flavor) or obtained by artificial substances/processes?
  2. Is it mandatory to label aromas derived from genetically modified organisms?
  3. Is the use of aromatic agents regulated in detail?

Food Colouring 

Various colors are added to foodstuffs to change the way they look natural and make them more appealing. People now associate the color of food with its health benefits; for our ancestors, it would be an indicator of something toxic or unsafe! The most appealing food colors, i.e. that makes you more hungry, are said to be green and red, while the least appetizing is blue.

Today dyes for food coloring may be produced from natural raw extracts (carotenoids, chlorophyll, etc.) or synthetic origin, derived from coal tar.

Natural colors are more stable, have a uniform coloration, and are more expensive.

Synthetic colors caramelize and are used mostly in the food industry (E 150a, E 150 b, E 150c E 150d) and the toxicity is mainly related to synthetic dyes.

However, there are many food safety incidents each year including colorants such as the one reported in China when unapproved colorants were found in red (coloring) spices, chili powder, curry, Worcestershire sauce, chicken in KFC, and raw materials originating from China.

Pesticide in textile aniline have potential carcinogenic effects and is prohibited in the US and England.

Approximately 0, 01-0.1% of the chemically sensitive population to artificial colors may develop serious allergic reactions (eczema, asthma, hyperactivity).