Introduction

The science of processing food has developed as a result of the complex nature of food conbined with the ever increasing distance between where food is produced and where it may be consumed. The ancient methods used in processing and preserving of food which such as salting, drying smoking are still in vogue but what we will be discussing today is the modern day use of food processing and preservation. There is need for research to be made on how to process and preserve our food due to so many factors like food poisoning, food contamination which may be detrimental to our health. There are varieties of factors which contributes to food poisoning and contamination and therefore there are various means of preventing the main types of food poisoning. But before that, lets talk about the basic methods of processing food.

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Food processing

Food processing is the various methods implemented in achieving and changing our agricultural products so as to make them edible for immediate consumption and preserved for future consumption. In other words, food processing is divided into two parts (i) food preparation (ii) food preservation. Food is been processed for many reasons such as aiding easy digestion since many of the nutrients are not readily available until been heated, increases the flavour of the food, making it soft to be chewed easily, making it safer for our health by killing the micro organism present in them and preserving it to avoid spoilage and contamination.

Methods involved in food preparation and processing

Separation and subdivision

This is the first step involved in preparation of food, this is very important so as to make food appealing and desirable to eat. Separation is the act of removing the parts of our agricultural products that are not needed and are harmful when consumed e.g removal of corn husk, pilling of potato. On the other hand, subdivision is removal of parts within the edible portion that will cause deterioration through spoilage. The methods involved in separation and subdivision of food includes cutting, pounding, grinding, peeling, paring, grating etc.

Combination and Mixing

Food is been combined and mixed together so as to achieve a desired taste and palatability. The processes involved are blending, beating, creaming, stirring, pressing etc. All this are done in order to increase and circulate the flavour of the food.

Heating

This is the most important of all the processes involved in food preparation. All substances in the universe contains heat but in various degrees. In order to change the structure or texture of a substance, we need to add or subtract heat from it. So heating of food is the process of increasing the heat present in our food in order words increasing the temperature of it so as to make them edible. When food are heated, it makes them soft which aids easy digestion and easy release of nutrients.

Cooling

This is the opposite of of heating. This is the process of removing the heat present in foods by cooling the environment that are placed. Refrigerators are the devices involved in cooling of food.

Chemicals

In modern day food processing and preservation, the use of chemicals is predominant. Chemicals are used to increase the flavour of foods and in long term preservation of food for example the use of salt (NaCl), monosodium glutamate is to improve the taste of our foods and the use of baking soda in the production of bread so as to make it rise. In recent times, many of these chemical processes are been questioned since it increases health risk.

Micro Organisms

The use of micro organism in food processing has been so important most especially to the food industries. These micro organisms serves various functions ranging from fermentation, to rising etc. It is important that the right amount, temperature and condition are provided because as useful as micro organism are, they are also the cause of food spoilage which causes food poisoning.

Food spoilage

In order for we to achieve a healthy and nourished body, we have to be cautious of what we eat and the processes involved in preparing what we eat. Food spoilage is an undesirable change caused by various factors which makes foods complete unsafe to eat. This changes can be detected by the smell, taste, sight or texture of the food. Food spoilage is caused by internal and external factors.

Internal factors

Enzymes are the main internal cause of food spoilage. Enzymes are naturally occurring in foods and they serve great importance such as breaking down of complex plant and animal biomolecules and in ripening of fruits. But the continuous activities of these enzymes causes rot and spoilage making the food inedible.

External environment factors

There are various external factors that are involve in food spoilage and they are

• Temperature : Temperature changes in the storage of foods is very essential to be taken note of. This is because, change in temperature promotes and support the growth of food spoilage agents and it also causes direct damage to our food e.g our vegetables and fruits tissue breaks down after freezing making them venerable to attack by micro organisms.

• Living things: The activities of living things such as bacteria, moulds, yeast, insects and rodents plays a crucial role in food spoilage. Some moulds and bacterias produces toxic substances in our food which are not noticeable in the eating quality and this are very dangerous to our health. While insects and rodents contaminates food with their hair and faeces which are dangerous to how health as they may lead to various diseases and infections.

• Moisture: the addition or the the removal of water from the original water content of food also leads to food spoilage for example, the removal of water from bread will make it very hard and on the addition of water to it, it creates a supporting environment where micro organism can harbour which in turn leads to spoilage.

• Oxygen - The presence of oxygen encourages spoilage in some food substance such as our vegetable oils. Rancidity which leads to distasteful smell and taste is is caused by oxygen in an uncomplete or complete oxidation reaction when fat and oil are exposed to air.

• Light: when some foods such as fruits and oils are exposed to light, they deteriorate and get spoilt quickly. Lights causes changes in taste and colour of fats when exposed for a long time.

When an individual consumes food which is spoilt or has been contaminated will lead to various complications which are discussed below

Food Poisoning

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The various factors which contributes to food spoilage which are discussed above sometimes leads to illnesses known as food poisoning. Food poisoning is caused by eating contaminated food by pathogenic microorganisms, parasites and their eggs, toxic chemicals and toxins. Symptoms of food poisoning ranges from mild stomach problems to serious clinical conditions.

Food Intoxication

This is another type of food borne illness as a result of toxins present in foods. These toxins maybe be present in food due to accidental contamination by farmers or may be present due to bacterias releasing toxins in food e.g clostridium perfringens is a bacteria that when consume in large amounts, produces toxins and spores which causes illness. Another well-known bacteria which causes food intoxication is the escherichia coli, which causes haemolytic uremic syndrome a kidney disease. It can get into the body by eating uncooked contaminated beef.

Food infection

Food infection is the process by which pathogenic orgaisms gets into the body of an individual through the food they eat. This organism causes various kinds of diseases and illnesses. For example, Salmonella which is the most common cause of food infection when ingested causes vomiting, abdominal pain, diarrhea, muscle weakness and nausea. These bacteria can only cause illness when consumed in large amount and when contaminated food are consumed raw or uncooked. Another cause of food infection is consuming of parasites or their eggs for example, pork meat contains a parasite called trichinella spiralis that is present in the muscle of pigs. When a contaminated pork is eaten uncooked or not cooked up 77°C which is the maximum temperature this bacteria can survive in, this parasites then grows in the intestine causing various illnesses.

Preservation and prevention of food spoilage

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One of the factors contributing to food spoilage is negligence. Micro organism which causes food borne illnesses are everywhere, but if we can prepare our food in a sanitized environment and store our food safely most of these food borne illnesses can be avoided. Lets take a look at the various ways by which we can prevent food borne illnesses

Food handling

Good food handling is very vital in in order to help prevent food borne illnesses. Foods that are cooked should be kept at temperature higher than 66°C until it is been served and foods that are not ready to be eaten should be well preserved in the refrigerator at 3°C and below. Although, placing your food in the refrigerator doesn't kill these bacterias but it will reduce the activities of these bacterias and prevent them from multiplying. The washing of hands and keeping clean the environment where food is been prepared is also very essential.

Controlling light

Since high light affects food that contains high fat and vegetables, it is advisable to keep these types of food off the reach of light.

Drying or dehydration as means of preservation

The act of dehydrating or removing water from foods makes the food unfavourable for micro organism to grow. Although, removing water from foods doesn't kill these bacterias so it is advisable to always boil these food before eaten. Dehydration changes the taste of foods since it concentrates the flavours but it helps preserve foods for a very long period.

use of chemicals for preservation

The use of chemicals to preserve food is more predominant in the food industries. The various chemicals used in the preservation of food includes salt, alcohol, vinegar, nitrate, antioxidants, smoke, nitrogen and organic fruits. Let's take the use of sugar for instance, we all know sugar is used to add sweetish flavour to our food, but it can be used in the preservation of food at a very high concentration. Industries that produces jam and jellies makes use of fruit juices and pulp and high concentration of sugar to prohibit bacteria growth.

use of micro organism

The process of fermentation is of great importance because it is been utilized for food preservation. In the process of fermentation, micro organism converts sugars into lactic acid without forming any other unwanted products thereby making the environment unfavourable for other micro organism since they depend on sugar for growth.

Controlling Oxygen

This method is what is been used in canning of food and beer by food industries. The process involves heat of foods to dry off air, replacing oxygen with other gases that don't support combustion and sealing the can in vacuum. These sealed food or beer can be kept for a very long time without getting spoilt.

Moisture control

Food that gets spoilt under high environmental humidity can be prevented from spoilage by appropriate packaging. In the industries, foods that get spoilt under these conditions are monitored using hygrometer and the air is also kept dry using drying agents such as sillica gels and alumina.

References for further reading

• Poti J.M. et. al., (2015). Is the degree of food processing and convenience linked with the nutritional quality of foods purchased by US households? Am J Clin Nutr. 101(6). Retrieved Aug 30, 2018 from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4441809/

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• Food industry process

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