Certain preservatives are harmful if abused – Olayinka

Food preservatives have been used for centuries and have become quite indispensable. On different occasions, however, people have worried about how safe they are. In this interview with Akoleowo Olayinka, a dietitian at Lagos University Teaching Hospital (LUTH), she enlightens on food preservatives and their effects on human health. GERALDINE AKUTU reports.

What is food preservative?
Food preservation can be defined as the science, which involves application of scientific and engineering principles to the practical control of food deterioration. It is also the methods of treating foods to delay the deterioration of the food or a way of changing raw products into more stable forms that can be stored for longer periods.

Food preservation allows any food to be available any time of the year in any area of the world. Preservation process includes, heating or boiling to destroy micro-organisms, oxidation, toxic inhibition, dehydration or drying, osmotic inhibition, freezing, a sort of cold pasteurisation, which destroys pathogens and various combinations of all these methods. The vast majority of instances of food spoilage can be attributed to one of two major causes:

The attack by pathogens (disease-causing microorganisms), such as bacteria and molds, or oxidation that causes the destruction of essential biochemical compounds and/or the destruction of plant and animal cells. The various methods that have been devised for preserving foods are all designed to reduce or eliminate one or the other (or both) of these causative agents.

What are the benefits of food preservatives?
Preservatives are natural or man-made chemicals that are added to foods to stop them from spoiling. To prevent spoilage of foods by molds, yeast and bacteria, preservatives have an acidic nature that makes the organisms unable to grow in food. Preservatives may act as the antioxidants, make the food more acidic, reduce the moisture level of the food, slow down the ripening process and they prevent micro-organisms growth.

Do they pose any health risk?
Although preservatives and food additives are used to keep the food fresh and to stop the bacterial growth, but there are certain food preservatives that are harmful, if taken in more than the prescribed limits. These harmful food preservatives are:

Benzoates
This group of chemical food preservative has been banned in Russia because of its role in triggering allergies, asthma and skin rashes. It is also considered to cause brain damage. This food preservative is used in fruit juices, tea, coffee etc.

Butylates
This chemical food preservative is expected to cause high blood pressure and cholesterol level. This can affect the kidney and liver functions. It is found in butter, vegetable oils and margarine.

BHA (butylated hydroxyanisole)
BHA is expected to cause liver diseases and cancer. This food preservative is used to preserve fresh pork and pork sausages, potato chips, instant teas, cake mixes and many more.

Caramel
Caramel is the colouring agent that causes vitamin B6 deficiencies, genetic effects and cancer. It is found in candies, bread, brown coloured food and frozen pizza.

Healthy, safe food preservatives
The following are some healthy, safe food preservatives to look out for: alpha tocopheral (vitamin E), ascorbic acid (vitamin C), calcium propionate, nisin, tartaric acid, and TBHQ.

Natural alternatives for food preservatives
In the category of natural food preservatives comes salt, sugar, alcohol, vinegar, etc. These are the traditional food preservatives that are also used at home, while making pickles, jams and juices, etc. Also freezing, boiling, smoking, salting and drying are considered to be the natural ways of preserving food. Coffee powder and soup are dehydrated and freeze-dried for preservation. Sugar and salt are the earliest natural food preservatives that very efficiently drop the growth of bacteria in food.

To preserve meat and fish, salt is still used as a natural food preservative. Modified packaging techniques, such as vacuum packing and hypobaric packing also work as food preservatives. Spices are also used for centuries to preserve food, most spices contain anti-microbial properties, as well as antioxidants, which slow the rate of oxidation. Commonly used for flavour and preservation garlic, cloves, cinnamon, onion, rosemary, bay leaf, oregano, thyme, mustard and sage. It is important to note that smoking of food is associated with cancer. Boiling leaches nutrients and highly salted foods are not recommended for those with elevated blood pressure.