For starters, here are some facts that are often not clearly understood
- Vegetarian food can be just as dangerous as meat based foods if not handled correctly
- Bacteria can multiply (slowly) in the refrigerator and are not killed by freezing
- Some bacteria produce toxins and spores that can survive boiling temperatures
- When food is contaminated with food poisoning bacteria there is no distinguishable change in flavor or appearance
- Bacteria all have different lifestyles; some like to be hot, some cold, some survive only with oxygen and some without. What is more, pH, salt and sugar levels are important factors
- Symptoms appear anywhere from one to fifty hours after eating contaminated food, making it difficult to identify the culprit
- Typical symptoms are nausea, vomiting, diarrhea and stomach cramps
- Symptoms can be fatal at worst but can also damage vital organs such as the kidneys

Most bacteria are harmless and many are needed to produce the diverse range of foods that people like to eat. Cheese, yogurt, beer, wine, bread and sauerkraut are just a few of the foods that we would be unable to make without them. Friendly bacteria are used in the food industry in a controlled way making the end product perfectly safe to eat.

Meat, poultry and fish are all high risk foods as they harbor their own specific bacteria and are easily further contaminated during preparation and storage. If you shop in traditional markets in Taipei, go early especially in the summer and take an insulated bag (including, if possible a freezie) with you to store perishable foods in. Bacteria, given the right environment and time, will double in number every twenty minutes. This may not sound that scary but since low levels of bacteria are counted in thousands in every gram of food, for bacteria to be present at a dangerous level per gram of food, figures in excess of 100,000 are the norm. Considering that there are 28 grams in an ounce and that you could easily consume eight to ten ounces of any given food at a meal, then scary is right back in there!

Food poisoning occurs in two ways; it depends on the type of food and bacteria responsible. These are known as food infection and food intoxication. Salmonella is an example of food infection as it is the high numbers of bacteria present in the food that cause the symptoms. The bacteria irritate the stomach lining and the intestines. Symptoms can be immediate or delayed depending on how empty your tummy was before you ate or your overall health. Babies, children and the elderly are more at risk from fatality from food poisoning than healthy adults. Two people eating the same infected food may not suffer in the same way, which often leads people to think that it was not the food they had eaten together that was responsible for their illness.

Food intoxication is caused by the bacteria producing a toxin (a poison) as a by-product when they are reproducing in food. Staphylococcus aureus, found in the nose and cuts and boils, and bacillus cereus found in all rice and other cereal products like pasta are just two culprits. Given the right environment, the bacteria grow in the food and toxin is produced. If the food is heated the bacteria will die but some toxins are able to withstand quite high temperatures. Many of the foods associated with this type of illness are those which are not always served hot like custard and cream cakes and salads with creamy dressings.

Rice is a food that should always be handled with respect. Poorly handled rice is responsible for many outbreaks of food infection around the world. Rice contains a bacterium called bacillus cereus which is present from when it is harvested. Bacteria cannot survive without water but some are able to develop a protective coating and survive in a dormant state until the environment is right for them. The ability to do this is known as spore forming. The spores of this bacteria are present in all rice and since rice is cooked in water that is when the problem can start. Rice in the home is usually cooked in small amounts then eaten immediately or used for a salad. If rice to be used later is cooked, quickly cooled and stored in a refrigerator it is safe to eat. If rice is cooked and then cooled slowly in a warm kitchen the spores, which will have survived boiling temperatures, will start to become active again and reproduce. At around 37 degree celcius (body temperature) the activity will be the fastest. Heat stable toxins will become present in the food. If the rice is cooked in large batches (as it is in restaurants) and cooled in the kitchen it can become unsafe to eat even if it is to be reheated before serving. The safest way to prepare rice for eating at a later stage is to cook it and then cool in a colander under running cold drinking water then place in a covered container in the refrigerator.

Time and temperature

In food hygiene training we talk a lot about time and temperature. This is because they are crucial in food becoming unsafe to eat. All food has bacteria in it but not all food is given the chance to become unsafe. Food becomes dangerous if it is allowed to sit in the danger zone - 5- 63 dgree celcius - for long periods of time (an hour or more). The optimum temperature for many bacteria is 37 (which is also body temperature) so if you are unlucky enough to eat contaminated food they will keep on reproducing in your stomach and intestines, although they will also have to combat stomach acidity and other bacteria.

I cannot conclude this article without mentioning cockroaches. We have to tolerate them in Asia they are part of the territory. Luckily they usually come out at night and we don't have to spend much time with them, but they do have a nasty habit of wandering over work surfaces looking for scraps of food, hair or nails. They are the lowest form of life and they certainly live up to this reputation by eating anything including faeces (their own or others', dead cockroaches or dead anything, as well as our food. They trample around with a cocktail of bacteria on their legs, so even if you wash your work surfaces before bed the chances are they will be contaminated by morning. You will not know for certain if you've been visited so do not take a risk. On the bright side, physical removal of bacteria is very easy and does not require chemicals, just hot soapy water and a clean cloth. Using spray-on sanitizers can contaminate food with chemicals and is quite simply a waste of money.

Remembering all foods contain bacteria, some more than others, follow these simple guidelines to make sure your kitchen is a safe place this summer!

- Keep your kitchen squeaky clean and always wash work surfaces prior to preparing food
- Only buy the freshest meat and fish from a reputable supplier (if you buy from the markets go early and take a cool-pack with you)
- Wash all fruit and vegetables before use to remove dirt and pesticide residues (removing skin if applicable is also a good idea)
- Refrigerate perishable food as soon as you get home
- Leftovers should be chilled as soon as the meal has finished ?never leave food lying uncovered if it is to be eaten later on
- Change tea towels and kitchen cloths that can harbor bacteria daily
- Never leave cooked food for more than thirty minutes to cool before chilling (large quantities should be portioned up to speed this up)
- Make sure your refrigerator is cleaned regularly and is not more than three quarters full, otherwise it will not work properly as air needs to circulate inside
- Keep raw and cooked foods separate in the refrigerator
- Try to keep your kitchen as cool as possible whilst you are preparing food
- Food should be kept out of the danger zone either cold (below 5 or hot , above 63 degree celcius)