Kitchen Hygiene and Food Safety
There are strict laws and regulations which control the standard of food. These deal with the production, distribution and sales, ensuring that the food is safe for us to buy. It is then our responsibility to choose, store, handle and prepare food in a safe and hygienic way to keep it safe for our family and friends to enjoy.
It is thought that many food poisoning cases originate in our own homes and with some basic knowledge of safe practices, the numbers of cases could be substantially reduced.
This module will explain some basic rules to follow when you are preparing food, to keep it safe to eat. It will also answer some questions about food poisoning – how it can happen, what causes it and how to recognize the symptoms. It is good to know that all forms of food poisoning are preventable and by understanding what the causes are then you, as the cook, will know how to produce safe food.
Buying Safe Food
Buy your food from reputable retailers with good standards of hygiene practices.
Ensure the dates, which are marked on the food (either use by or best before), are within the time scale that you need.
Do not buy too much highly perishable food unless you are absolutely sure that you can use it within the stated time.
Once you have bought your food, if any of it is chilled or frozen, it needs to be taken home as quickly as possible, to return it to chilled or frozen storage.
Don’t buy food in faulty or damaged packaging as this increases the likelihood of it becoming contaminated.
Food Handling and Kitchen Hygiene
However carefully you select your food, you must remember to store it and handle it hygienically at home.
Your kitchen and storage areas should be kept scrupulously clean. This does not been they have to be sterile, a certain amount of bacteria are everywhere. Many people are concerned that we are living in a too clean environment.
However there is a balance to be reached and where you are dealing with food, then it has to be agreed that a good level of cleanliness will help to prevent a case of food poisoning. Modern kitchens and the materials used have helped make cleaning much easier than it used to be, but cleaning still has to be done.
Detergent – e.g. washing up liquid. This is used with hot water to remove grease and dirt from equipment or surfaces.
Disinfectant – this is a chemical which reduces bacteria to a safe level. It is important to check that there is no grease or dirt present before using a disinfectant.
Anti bacterial products – these are often a combination of cleaner and disinfectant, but check on the instructions usage advice.
A Cleaning Checklist
Always clean your worktops before preparing food.
Clean your worktops thoroughly after you have prepared food, particularly if you have been using raw meat, poultry, fish or unwashed vegetables.
Dishwashers are a very effective way of disinfecting dishes, utensils and you will probably find that most chopping boards can be washed this way.
Dishcloths can be a perfect place for bacteria to multiply, so get into the habit of cleaning them often, then rinsing in very hot water, squeezing them dry, then allowing them to air dry. Don’t leave them in a damp bundle on the sink.
Disposable kitchen towels are very useful and can be used to dry down surfaces that have been cleaned, then just throw the paper away.
Tea towels can harbour bacteria if allowed to be stored in a damp state. There will be little need for them if you rinse your dishes in very hot water and allow them to air dry.
Keep you hands clean, they are an effective way of passing on bacteria from one food to another.
The best advice would be to Clean As You Go.
Storage of Food
Earlier, mention was made about the importance of placing chilled and frozen food into the fridge or freezer without delay after you have brought the shopping home. In this section we will discuss how to store this food.
It is advisable to have a fridge thermometer which should show that the temperature inside your fridge is below 5C. This will in most cases stop the growth of bacteria, and certainly slow it down so they will not multiply to dangerous numbers.
Do not have too much food in the fridge, this will not allow the air to circulate properly and the fridge will then not operate efficiently.
Always keep raw food on the lower shelves and the cooked food above, this way any ‘drips’ cannot contaminate ready to eat food.
Never put hot food into the fridge. This will cause the temperature of the fridge to rise, and the refrigerated food already in there will begin to warm up.
Cover food well, to prevent it from becoming contaminated and it will also prevent it from drying out so that the quality will be maintained.
Check the contents often, to ensure you are not keeping foods for too long, remember all of those jars etc. will have recommendations on the label, e.g once opened, refrigerate and use within 3 days, or weeks etc.
Never put open tins into the fridge, any contents left should be put into a suitable container, covered and then refrigerated – the reason being that it is a possibility that the food could become contaminated by the aluminium in the can.
Get into the habit of always closing the fridge door immediately after you remove anything. This will help to maintain the correct temperature in the fridge.
Clean your fridge often, paying particular attention to the handle. Use an odourless cleaner – bicarbonate of soda is highly recommended even though this is seen as old fashioned – anything strong smelling will linger in the fridge and possibly taint foods which are stored there.
The temperature which your freezer should be operating at is –18C. You may consider that a thermometer would be useful in your freezer as well.
Never re-freeze foods which have been thawed and not used. This is because the food will have risen in temperature which could allow bacteria on it to become more active and begin to grow and multiply.
You must wrap food well for the freezer. Remember cross contamination can still occur in the freezer. Also, foods not wrapped adequately could suffer from freezer burn, which, inn effect, dries up the surface of the food which particularly reduces the quality of the food, but also can result in the food becoming ‘spoiled” and a reduction of the nutritional quality.
This point relates more to the efficiency of the freezer, but it is best to keep it fairly full. Only allow the quantities to run down if you are expecting to do a major shop, or you grow your own produce and you are expecting to have a glut of fruit and vegetables.
Always, when freezing your own food, remember to label it with the date and what it is, otherwise you will end up trying to guess a few weeks later – the food can look totally different sometimes in its frozen state.
When thawing food, follow manufactures advice if there is any. Produce like raw meat or poultry should be placed in a container and placed in the fridge. You could defrost in the microwave, but if so, cook it straight away.
About Food Poisoning
Food poisoning is a very unpleasant illness for which the main symptoms are stomach pain, vomiting and diarrhoea. It usually occurs between 1 and 36 hours of eating the contaminated or poisonous food and the illness usually lasts between 1 day and a week. In some cases the illness can cause permanent disability or can even be fatal, particularly to those groups of people that are known to be vulnerable i.e. the elderly, the very young, pregnant or nursing mothers or those who are already ill or may be immune deficient.
Food poisoning is caused by :-
Bacteria or their poisons
Remember, food poisoning does not just happen – it is caused – and this is due to something going wrong in the chain of events before the food is eaten. It is thought that many food poisoning incidents occur in people’s own homes, as was mentioned earlier.
Food poisoning caused by bacteria is most common.
Foods which have been contaminated by these harmful pathogens look, smell and taste quite normal.
One of the main reasons for food poisoning is the storage of high risk foods at room temperature for too long e.g. sandwiches made up in advance and not chilled.
Other reasons are:
Cross contamination between raw and cooked foods
Poor hygiene practices of the person handling the food
Careless use of left-overs
Not reheating food thoroughly
Bacteria – What are they?
They are microscopic organisms which are found everywhere and are invisible to the human eye, although they can be seen through a microscope.
Not all bacteria are harmful – in fact the majority are harmless, many are beneficial, for example those naturally present in milk which are responsible for the production of yogurt and cheese. We also require bacteria in our bodies to help us digest food.
Then there are some harmful bacteria which cause food spoilage and then the pathogens which cause illness like food poisoning.
Bacteria need certain conditions to multiply and grow – these are
In perfect conditions these bacteria can multiply very quickly – every 10 to 20 minutes. They multiply by dividing in two and this is known as binary fission. In effect, this means that in perfect conditions 1 bacterium could become more than 1 million in less than 4 hours.
Bacteria thrive in warm temperatures, 37C would be perfect. This is why it is recommended that those foods which are most at risk from bacterial growth are kept refrigerated, below 5C. If you are cooking food and keeping it to eat later, either keep it hot – above 63C, or cool it quickly and refrigerate it. Then reheat it quickly and thoroughly.
Bacteria prefer foods with a high protein content. Examples would be:
Cooked meat and poultry
Home made stocks – gravies and soups
Dairy foods and dishes made with them
Rice and pasta dishes
All of these foods should be refrigerated whilst they are being stored.
Moisture is also needed, but any of the foods listed above would contain sufficient moisture to support the bacterial growth.
Salmonella - There are many different species of salmonella and all in all they account for a very large proportion of the reported cases of food poisoning. Typical incubation time would be between 12 and 48 hours, but this could differ to be less or more time. The symptoms would be diarrhoea, vomiting, fever and stomach pain. The usual sources would be raw poultry and meat, raw eggs and cross contamination from faeces, rodents, insects, birds and maybe even your pets.
To prevent this bacteria from causing food poisoning:
Cook foods thoroughly – salmonella are readily destroyed by heat
Avoid raw foods coming into contact with cooked foods
Thorough cleaning and disinfecting
High standards of personal hygiene – WASH YOUR HANDS OFTEN
Staphylococcus Aureus - About 40% of the population are carriers of this type of bacteria. It is carried in the nose, throat and mouth and also present around septic cuts, wounds boils and grazes. The symptoms are severe but only for a short period. You would be vomiting within hours of eating the contaminated food, but it rarely lasts longer than 24 hours. It is therefore extremely important for food handlers remember to wash their hands thoroughly – often.
When it gets on to food it produces a toxin, which makes the food poisonous.
To prevent this type of food poisoning:
High standards of personal hygiene
Handle food as little as possible, using tongs or other suitable equipment
Never use your fingers to taste food, and if you use a utensil, thoroughly wash and disinfect before using again.
If the food is not going to be eaten immediately the refrigerate it, or if it is hot food, keep it hot.
Clostridium Perfringens - This is different from the previous 2 types of bacteria in that it is not completely destroyed by heat. At higher temperatures it can form spores which can withstand extremes of temperature and cannot be destroyed by normal cooking.
If the contaminated food is then allowed to stand at room temperature the outer shell is dissolved and growth and multiplication starts again. Symptoms of this type of food poisoning would be stomach pain and diarrhoea and these would begin 12 to 48 hours after eating the contaminated food. It is found in raw meat, vegetables, soil and dust. It is quite often associated with reheated foods like casseroles or meat pies.
To help prevent this from happening:
Always keep your raw foods and cooked foods separate, including vegetables
Cool cooked foods quickly, then refrigerate
Avoid reheating food, but if necessary bring it to a high temperature as quickly as possible and serve as quickly as possible.
Never reheat foods more than once.
Bacillus Cereus - This is another type of bacteria which is a spore former and therefore is not destroyed by normal cooking. The symptoms of vomiting and stomach pain usually occur a few hours after eating the contaminated food. The most common foods associated with this type of food poisoning would be cooked rice, pasta and sauces made from cornflour.
To avoid this type of food poisoning:
Avoid reheating – certainly do not reheat more than once (a common problem is reheated rice)
Chill foods rapidly and refrigerate if not eating straight away e.g. rice and pasta salads, custards.
If you do reheat, then do it quickly and to a high temperature.
E.Coli (Escherichia Coli) - This is a bacterium naturally found in the intestines of man and animals. Only certain strains are known to cause food poisoning – these can cause severe abdominal pain and diarrhoea, being particularly dangerous to those who are vulnerable to illness. The particular strain which has been involved in recent outbreaks is known as E.Coli 0157 and is classed as a food borne infection – this means that it is carried on the food and then when you eat the food you become ill.
To prevent this causing food poisoning:
Thoroughly cook the food – remember it is carried on the surface of food like raw meat, so make sure that the surface reaches a high temperature. This is often associated with minced meat products because the meat is all chopped and minced, and therefore what was once on the surface could now be in the centre, so thoroughly cook – all the way through – for dishes made with minced meat, e.g. burgers and sausages
Make sure you completely separate raw meat and cooked
Thoroughly wash your hands before preparing food
Campylobacter - There are many different types of this, Campylobacter Jejuni is the one linked with many outbreaks of food poisoning in this country. It causes diarrhoea and is generally thought of as a food or water borne infection rather than food poisoning.
If these bacteria are present in food or water they do not tend to multiply in it, however, once swallowed the bacteria can multiply in the gut causing illness. They are easily killed by heating. As they are often found on chickens, this emphasises the need for thorough cooking and washing hands after handling raw poultry. However it has also been associated with milk, which is often used as it is.
One particular way that milk has been known to become contaminated is by birds pecking at the foil top. If you suspect that this has happened, do not use the milk for safety – or only use it for cooking.