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 odour, bitter flavour, and change in colour.
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, cotton seed 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 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 flavourings for better appearance and consistency, both natural and artificial colours, emulsifiers, and other.
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 labelling 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 sensitisation.
Side Effects Of Food Preservatives and Additives
Sulphur 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 sulphite 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 anti fungal agent, is used for the crust of cheese and sausages. Experts warn that the overuse of antibiotic in food may lead to antibiotic resistant bacteria.
Aromas & Enzymes In Food Industry
Aromas (flavours) are substances derived from physical, enzymatic or microbiological processes from plantsand/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 flavouring substances, flavouring products, and smoke flavourings and its mixtures. There are natural and artificial flavours, 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
- 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 flavours
- 03 g/ kg 3,4-benzopyrene in flavoured products and beverages
The following questions still remain unclear:
- Do the regulations on labelling of flavourings oblige producers to declare whether it is natural aroma (traditional food preparation methods such as natural lemon flavour) or obtained by artificial substances/processes?
- Is it mandatory to label aromas derived from genetically modified organisms?
- Is the use of aromatic agents regulated in detail?
Various colours are added to foodstuffs to change the way they look naturally and make them more appealing. People now associate the colour of food with its health benefits; for our ancestors it would be indicator of something toxic or unsafe! The most appealing food colours, i.e. that makes you more hungry, are said to be green and red, while the least appetizing is blue.
Today dyes for food colouring may be produced from natural raw extracts (carotenoids, chlorophyll, etc.) orsynthetic origin, derived from coal tar.
Natural colours are more stable, have a uniform coloration and are more expensive.
Synthetic colour caramelis 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 (colouring) spices, chilli 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 colours may develop serious allergic reactions (eczema, asthma, hyperactivity).