Preservatives are used to prevent bacteria, yeast and mould growth, preserve colour and flavour and keep food from going bad by preventing oxidation.
It can be hard to avoid preservatives as they can be found in almost any type of food or drink.
There are many natural preservatives such as salt, vinegar and sugar, but most of the preservatives used by food manufacturers are synthetic.
Potassium Sorbate (202) is used to prevent mould growth in foods such as cheese, cheese based products, yoghurt, wine, dried meat, pickles, apple cider, dips and many herbal dietary supplements.
In a study done in Turkey, potassium sorbate was found to be genotoxic to the human peripheral blood lymphocytes in vitro (ie: causes damage to the DNA).
Sodium Benzoate (211) is used in carbonated drinks, oral medications, mouthwashes and added to acidic foods such as pickles, fish and oyster sauces, salad dressings, jams and fruit juices to enhance their flavour.
Even though sodium benzoate is found naturally in cranberries, plums, prunes, apples, cloves and cinnamon, it does not play the role of a preservative in these fruits and spices.
Sodium benzoate has anti-fungal and anti-bacterial properties. It works by entering the individual cells in the food and increasing the overall acidity of the food, thus creating an environment in which microbes and fungi cannot grow and spread.
When mixed with vitamin C, sodium benzoate forms benzene, a known carcinogen. The rate at which benzene is formed is affected by exposure to light and heat, as well as the time spent on the shelf from production to consumption.
Some studies have shown that sodium benzoate along with artificial food colourings may increase hyperactive behaviour in some children.
Sulphur Dioxide (220) and Sulphites (221 – 228) are used to preserve the flavour and colour in fruits, dried fruits, vinegar, juices, cordials, soft drinks, sauces, beers and wines.
Sulphites inhibit bacterial growth, reduce spoilage, prevent browning of fresh food and help preserve medication.
Sulphites release sulphur dioxide, which is the active component that helps preserve food and medication.
According to The Australasian Society of Clinical Immunology and Allergy (ASCIA), sulphites can cause allergy and hay fever like reactions, wheezing in asthmatics, occasionally hives and very rarely severe, life-threatening anaphylactic reaction.
In Australia, Propionates (280-283) are commonly used to prevent mould growth in bread and bakery products.
Recently, propionates are also permitted in cheese, fruit and vegetable products.
Very few people realise they are affected by this preservative as most people only notice a difference if they switch to preservative free bread.
Reported side effects include migraine, headaches, stomach upsets, skin rashes, nasal congestion, depression, tiredness, irritability and restlessness.
Bakers who keep their baking equipment clean and mould-free by wiping with vinegar daily, do not need to use propionates as mould inhibitor because a freshly baked loaf of bread does not contain any mould.
However, in large scale, commercial baking factories, hot loaves of bread are commonly put in plastic bags and this predispose to mould formation.
Sodium Nitrate (250) and Sodium Nitrite (251) are used in processed meat such as bacon, ham, sausages, hot dogs, luncheon meats, cured meats and smoked fish to preserve the meats and inhibit the growth of bacteria that causes botulism.
They are also used as a colour fixative to give meat the bright red colour and makes old, dead meats appear fresh and appetising.
When used for curing, nitrates react with the meat tissues to form nitrites. Nitrites can react with amines in meats to form nitrosamines, a class of potent carcinogens found in cigarette smoke.
Food Standards Australia New Zealand restrict food manufacturers from putting these preservatives in baby foods but not on foods typically consumed by many children such as hot dogs and luncheon meat.
Infants are very susceptible to nitrate toxicity as they can develop methaemoglobinemia or “blue baby syndrome.” Nitrates may convert to nitrites in the digestive tract. Nitrites can combine with haemoglobin to form methaemoglobin which lacks the ability to carry oxygen in the blood.
So, are these preservatives safe?
According to the regulatory authorities, most of the synthetic preservatives are safe in the quantities in which they are found in individual food products.
However, think about all of the food and beverage you consume in a day. The quantities of those preservatives you are eating add up in a day and over your lifetime. There are no long term safety studies on the cumulative effects.
10 Tips on How to Avoid Harmful Preservatives in Your Diet
- Eat fresh, whole foods that are cooked by you.
- Avoid processed or pre-packaged foods as much as you can.
- If you do choose pre-packaged foods, read the ingredients on the label carefully and avoid foods that have harmful preservatives.
- Choose foods that contain natural preservatives such as ascorbic acid, citric acid, vinegar, salt and sugar. However, do watch and limit your overall intake of salt and sugar as overconsumption is detrimental to your health.
- Avoid processed or cured meat as much as possible.
- If you feel like having the occasional ham & bacon , look for nitrate- and nitrite-free bacon and other processed meats at your local butcher shop.
- You can make your own cold meat for sandwiches. When you cook a roast, why not cook a bit extra, slice it into portions and then thaw and use as required.
- If you want to avoid preservatives in bread, you can bake your own bread at home. Invest in a bread maker which is easy to use. Nothing beats the wonderful aroma of freshly baked bread!
- Ask for preservative-free bread and bread products at your local bakery.
- Go organic. One of the safest and easiest ways to avoid preservatives is by eating certified organic food and food products.