Food Contamination and Prevention

Food Contamination

Everybody at one time or another has had the experience of eating food and sometime later becoming sick. This is called food poisoning. The symptoms may include nausea, vomiting, stomach pains, diarrhea, feeling weak, fever or chills/sweating and headache etc. Food poisoning can be caused by eating food contaminated with bacteria, viruses, chemicals or poisonous metals such as lead or cadmium. Food which has become contaminated with harmful bacteria does not always taste bad. Where it looks smells and tastes like it normally does in most of the times. However, some food poisoning diseases are more common than others, i.e. disease caused by Staphylococcus aureus occurs a lot more often than disease caused by Clostridium botulinum. Thus food contamination is a major problem in the consumer market which may be considered as the occurrence of any obnoxious problem within or on the food. i.e. slaughtered carcasses may be contaminated with spoilage or food poisoning bacteria while grains can be contaminated with rodent droppings or hairs. Thus prevention of consumption of such food is necessary to control food poisoning where minimizing the contamination from such sources is mandatory. On the other and contaminated food will create havocs in market where manufacturer loose the consumers while he is liable for the causes generated.

Food Safety Hazards

There are four kinds of food safety hazards or contamination types, which are:

Microbiological Hazards

Microbiological hazards caused by microorganisms such as bacteria, mould, viruses and parasites. The root causes of biological contaminations in food production facilities are usually occurs due to ignorance, poor design, inadequate space, or due to the wrong practices used by food handlers. These types of problems are not visible in the initial stages, but such contaminations are very dangerous which may result in food spoilage, food poisoning and death.

Physical Hazards

Physical hazards are occurs due to the foreign objects including insects. Physical contaminations are usually unpleasant or nuisance which leads to food is unfit or unsafe for consumption. The usual objects are plastic, glass, stones, paper, hair string or metal.

Chemical Hazards

Chemical hazards are basically due to the addition of unwanted or overdosed chemical compounds which may be used for other proposes within the manufacturing facility. The chemical contaminations also lead to food spoilage, food poisoning or death. This includes pesticides, herbicides, cleaning chemicals as well as overdosed preservatives or other additives.   

Allergenic Hazards

The allegiances happen due to extra sensitivity of certain consumer groups such as young and elderly or pregnant due to the abnormal reactions by the immune system where immune system generates antibodies by misjudging the certain food products. The allergenic reaction can cause minor irritation to the immediate death. The major food allergenic foods are milk, peanuts, eggs and cereals.       

Microbiological Hazards

Bacterial contamination of food is the most significant among all the food poisoning incidents, because bacterial growth is very fast and their environmental requirements are diverse where they spoil large amounts of food products in various processing steps while generating lots of food poisoning outbreaks.  The source of contamination of microbiological hazards can be listed as;

Raw materials such as fruits, vegetables, cereals, poultry, meat, milk, eggs or fish etc.;

Insects, rodents, animals and birds;

Working environment including soil or dust;

Food handlers or visitors;

The mould spores are present in the environment which includes air, surfaces and mould contaminated foods. Thus all the food must be coved or keep airtight while segregating them from the mouldy foods. In addition, mould growth over tabletops, walls, ceilings and window frames or window sills must be prevented which happens due to the optimum temperature for growth, high humidity and availability of food source as well as excess of recommended shelf life. The other major reason is mechanical damages to the product packaging expose food to the environment which create contamination opportunities and mould growth inside the product.  

The viruses are usually contaminated through food handlers and visitors, or through raw materials such as shellfish which have been grown in sewage-polluted water.

Microbial Food Spoilage

Damage to food that is caused by microorganisms (bacteria, moulds and yeasts) and they can grow in almost all kinds of food products. As they occur everywhere around us, there is always a risk of microbial spoilage and most of them can grow in a variety of products under the right conditions. The growth is dependent of the kind of food, the type of microorganism, the temperature and other factors.  I.e. Dry products such as bread and cookies do not have enough moisture to allow bacterial growth where spoilage to these products is usually caused by moulds. Sour, salted or sugary products do not provide good growth environments for most microorganisms. They can be harmed by specific spoilage flora that have adapted to them.

 

Bacteria are round, rod or spiral shaped microorganisms. Bacteria may grow under a wide variety of conditions. There are many types of bacteria that cause spoilage which can be further divided into spore-forming and non-spore forming. Bacteria generally prefer low acid foods like vegetables and meat. In order to destroy bacteria spores in a relatively short period of time, low acid foods must be processed for the appropriate length of time at 116°C (240°F) in a pressure canner.  Yeasts growth causes fermentation which is the result of yeast metabolism. There are two types of yeasts true yeast and false yeast. True yeast metabolizes sugar producing alcohol and carbon dioxide gas. This is known as fermentation. False yeast grows as a dry film on a food surface, such as on pickle brine. False yeast occurs in foods that have a high sugar or high acid environment. Moulds grow in filaments forming a tough mass which is visible as `mould growth'. Moulds form spores which, when dry, float through the air to find suitable conditions where they can start the growth cycle again. Mould can cause illness, especially if the person is allergic to molds. Usually though, the main symptoms from eating mouldy food will be nausea or vomiting from the bad taste and smell of the mouldy food. Both yeasts and moulds can thrive in high acid foods like fruit, tomatoes, jams, jellies and pickles. Both are easily destroyed by heat. Processing high acid foods at a temperature of 100°C (212°F) in a boiling water canner for the appropriate length of time destroys yeasts and moulds.

Modes of Bacterial Contamination   

The contamination of bacterial cells are mostly depend on the carriers rather than direct contamination from the source to high risk foods, because bacteria are largely static and the source is not directly in contact with food product. Thus bacteria have to rely on other sources of transportation to the food product which are called as vehicles of contamination. The major vehicles are;

Hands

Hand-contact surfaces

Cloths and equipment

Food-contact surfaces

The contaminations routes are mostly indirect where cross contamination is the major route. The cross contamination is called as transfer of bacteria or spores from contaminated food to uncontaminated foods. The path which was used by bacteria to transfer from the contaminated food into uncontaminated food is called route. Thus creation of awareness on sources, vehicles and routes are very important in prevention of microbiological contamination. I.e. if the food handler understand that, use of unwashed hands between raw and cooked foods preparation, or use of the same equipment without cleaning or non-sanitized table tops can transfer bacteria from raw foods to cooked foods, he will sanitize his hands as well as with other necessary precautions to eliminate the problem.

If you are really considering of preventing microbiological contaminations, you must assume that, all the equipment, machinery, work surfaces and the environment are contaminated with bacteria where you will control all of them before start the production.  The prevention of contamination based on the removal or eliminating of the sources or building barriers between bacteria and the vehicles or source and the foods where human access to food must be restricted, while raw foods handle in separate areas with appropriate pest control mechanisms. Furthermore, work areas must be enclosed into properly designed, suitably constructed and ventilated buildings and movements of vehicles must be minimized as much as possible and handling of products must be minimized. Minimize the use of wiping cloths or destroy them immediately after each use, hand contact surfaces. Use knee, elbow or electronically operated taps in the production areas instead of hand operated taps. Limit the number of surfaces to be contacted while preparation of foods. However, routes between sources and vehicles survive giving rise to the contaminated vehicles where routes must be disrupted by cleaning and disinfection on a routine basis.

Preventive Controls for Contamination

Use of registered and certified suppliers who are well known and reliable for raw materials, ingredients and other food items.

Verify before accepting all the deliveries for the GMP which needs to be transported in properly cleaned and equipped vehicles with clean drivers wearing satisfactory protective clothing. Refrigerated vehicles and application of cold chain practices may be a necessity.

Verified goods must be transferred immediately to an appropriate cold or dry storage according to the raw material storage requirements.

Remove and return rejected materials to the suppliers, segregate chemicals, spoiled food items, refuse and store or discard them accordingly. Use food containers only for storing predefined materials.

Segregate high risk food items from raw materials and store separately, with separate utensils and equipments as well as with separate food handlers whenever necessary. Application of different colour codes will be helpful.  

Strictly maintain scrupulous personal hygiene at all levels and at all the times while handling food as little as possible and exclude potential carriers.

Keep food items covered or otherwise protected if it is not under preparation or processing, and don’t take out of stores if food items are not being utilized for processing. Don’t leave foodstuffs are lying around.

Maintain food hygiene on the premises, cleaning of utensils and equipment as well as repairs to be complete without delays. Disinfect the food contact surfaces, hand contact surfaces and cleaning equipment.

Ensure that all empty containers are clean and disinfected prior to re-filling with foodstuffs.

Control cleaning materials, particularly wiping cloths. Keep cleaning materials away from the foodstuffs. Remove foodstuff and food containers before cleaning where care must be taken ensure that all cleaning residues, including water are drained from equipment and pipes. The cleaning must be start from high risk areas to low risk areas.

Remove waste foodstuff and refuse from the food processing and storage areas as soon as possible which must be stored in appropriate containers away from food items.

Maintain an active pest control programme.

Control of visitors and food handlers in high risk areas are vital to control of food safety where application of hygiene disciplines to all operators including management is mandatory.

Inspection of food manufacturing areas, and processes in a predefined frequency is necessary where care must be taken to act fast on defects or unhygienic practices detected. Train the staff and use performance evaluations to see the impact where food handlers and engineers must be aware of the bacteriological and physical contamination and their impact on human health.

Ensure adequate thawing of foods, and separate from other foodstuff.

Make suitable provisions for cooling food items prior to refrigeration.