Prevention of Food Poisoning
The primary purpose of your refrigerator and freezer compartments is to to store your food at the proper temperatures to prevent spoilage. But what is spoilage anyway? And when does it become toxic?
When we deal with food preparation and storage, we generally all rely on our previous experiences, habits, or methods passed down to us from previous generations. After all, if the evolution of this knowledge is based on the continuation of the successful techniques we have observed and learned, we should be able to continue on without ever having an incident. Right?
Not always. The last time you and your family had a stomach flue or virus, could it have been a mild case of food poisoning?
Your refrigerator is an important piece of equipment that provides the right internal environment for storing food in a healthy way. The reason this article has been included in this book, is to help you to know scientifically what the causes of common food poisoning are, and how to prevent them from happening in the first place. Imagine the embarrassment of poisoning your dinner guests. It has happened many times, even to people that keep their kitchens spotlessly clean and have cooked for their families with no previous problems for many years.
Be informed, don't let this happen to you.
Bacteria
Some bacteria cause food spoilage, some cause food poisoning. Bacteria are one celled micro-organisms, sometimes also known as germs, that are virtually everywhere. These entities are so small you could put over one million of them on the head of a pin and the truth of it is, all living things live in an environment teaming with bacteria all around them. Most bacteria are not harmful to us, in fact, certain bacteria are even present in our bodies that are critical to the digestive process. There are however a few common varieties, that if ingested in sufficiently high numbers, will cause food poisoning. These are known as pathogenic bacteria.
Sources of pathogenic bacteria
Pathogenic bacteria are in most cases already present in the food you buy from the store, however it can also be induced into food during preparation:
* by insects
* by particles that get into food such as pet hair
* transferred to the food by our hands
* placing our food in or on a previously contaminated surface
The presence of poisonous bacteria on food in small numbers is not going to cause us any harm, but when the right conditions are present for harmful bacteria to multiply, then we have a problem.
Conditions for bacterial growth
When we say that bacteria grow, it doesn't mean that they grow in size. What it actually means is that they increase in numbers. What happens is that one cell divides into two, then later these two also divide into two, making four, and so on. The mathematical principal involved when doubling the product of a number previously doubled causes massive numbers to be present in a short period of time. Fortunately for us, pathogenic bacteria only multiply under the right conditions.
The first condition is temperature
The ideal temperature for pathogenic bacteria to grow the fastest, is the temperature of our bodies. When other ideal conditions are present, the bacteria will double in numbers every twenty minutes. As temperatures rise, growth slows down, until at 122*F (50*C) very few can grow at all. If the temperature is increased to 145*F (62.7*C) degrees or above, bacteria will be killed. Most bacteria are killed in just over 2 minutes in boiling water, but not all. Also, some bacteria produce toxins that are left on the food that remain harmful even when the bacteria that produced it have been killed by high temperatures.
On the other end of the scale, bacterial growth slows down when temperature decreases until it stops at about the temperatures that are present in a refrigerator. It is important to note however that even though bacteria growth has stopped, the low temperatures even present in a deep freeze will not kill the micro-organisms. You could think of them as being in a type of suspended animation. As soon as the food is warmed up, the bacteria again start to multiply.
The second condition is food
Pathogenic bacteria are living organisms that need a certain type of food to exist. Some foods are better than others at creating the right conditions that bacteria can thrive in, which generally are ones that are high in protein and moisture.
Foods that normally sustain bacteria are:
* meat and meat products
* gravy
* dairy products
* stew
* fish
* cooked rice
* cooked vegetables
Foods that do not normally sustain toxic bacteria are:
* dehydrated and dry foods, biscuits, and flour
* butter, margarine, and cooking oil
* citric fruits
* salty foods such as potato chips, olives, anchovies
* sugar foods such as jams, jellies, syrups, and candy
* pickles, relish
Remember bacteria are very small and they can thrive on just a crumb of the right kind of food left in a dish or on the cutting board. Also, when foods are dried, such as flour or dehydrated soup, bacteria can still be present, but like in the cold temperatures of your refrigerator they are in suspended animation, ready to come back to life as soon as water is added and the right conditions are present.
Keep in mind that even though pathogenic bacteria do not normally multiply in the temperatures present in your refrigerator, there are many non-poisonous ones that do. These can cause wilting, rotting, and more generally, a gradual flavor change in foods. All stored food whether stored in the refrigerator, freezer section, or deep freeze have a limited life.
So now that you are equipped with some of the main principles involved and a basic knowledge of the causes of food poisoning, the rest of this article will take the question and answer form. This is to further clarify and expand your knowledge on this subject by bringing some specific details into play.
Can someone die from food poisoning?
Yes, but it is quite rare. In the cases where it does happen, it's usually in the sick, elderly, or in small children. When preparing food for people in this category, special care must be taken.
My freezer stopped working, can I still use the food?
If it is partially thawed or thawed and still cold, you could cook it and refreeze it for later use. Or if the surface temperature of the food is not above 40*F (4.4*C) you could refreeze it but quality will be lost due to cell wall disruption. See page 178 for more details.
How do I know if I have food poisoning?
When you consume food that has high levels of toxins, as soon as the danger presents itself to your internal chemical system, your body will set off a protective mechanism that triggers vomiting, diarrhea and abdominal pain. In more severe cases the toxins can enter the blood stream through the small intestine. This situation causes many other symptoms to take place.
How long after the toxic food is consumed till these symptoms occur?
This varies with the type of bacteria that caused the poisoning and the amount of it consumed. Generally speaking you could say from between 2 to 48 hours.
Is pathogenic bacteria the only cause of food poisoning?
No, food can also become toxic because of harmful chemicals present in it. This can happen in the home because of careless use of insecticides or detergents. Or it can happen when the food was prepared at the food processing plant, or when it was grown. Also, there are some plants that are naturally toxic such as rhubarb leaves, toad stools, and some varieties of mushrooms.
If I bring food to its boiling point will the danger of food poisoning be gone?
Not always. Some bacteria produce separate or free toxins. These type of toxins would only be killed after boiling for over 1/2 hour. The only way to prevent poisoning is to prevent bacterial growth from happening in the first place.
How much toxic food does one have to eat before illness occurs?
This depends on your relative state of heath. It is estimated that a healthy adult must eat one million bacteria before any symptoms occur, however in a child or a person in old age only one tenth this amount can cause problems. Don't forget, over one million bacteria can be present on the head of a pin.
How do pathogenic bacteria get into food in the first place?
In meat or poultry the bacteria is often present on the surface of the meat when the animal is butchered. Bacteria can be introduced into the food in the processing or preparing stage if bacteria is present on the hands of the person working with it. Bacteria can also be introduced from a tasting spoon placed back into the food during cooking, insects, especially flies, and animals carry pathogens that can be transferred to the food. The soil in your garden contains it. It can be transferred from one food to another by chopping boards, knives, hands, and dishes. Bacteria can be introduced by a sneeze, or an infected cut on a finger, or even by using your hands to scratch another part of the body while preparing food.
Remember, you can do all you can to prevent it from getting on the food in the first place, but you can do a lot more about not letting it grow.
How can I prevent it from growing?
Don't let food sit around too long at room temperature. Keep it either very hot or cold like the temperature of your refrigerator. Bacteria could be multiplying in food that is simmering on top of your stove or in a warming oven that is less than 140*F ( 60*C ). Reheat leftovers only once.
The cheese in my fridge has some mold on the surface, can it still be eaten?
Mold is not pathogenic, however it will spoil the flavor and it is undesirable. Its effect on cheese in a solid piece is rarely very far below the surface. Foods that can transfer the foul taste of mold such as bread or fruit and meat cannot be eaten.
Are dishes that are just washed bacteria free?
Dish washing detergent cannot kill bacteria, you wash to remove all food particles. Automatic dishwashers in good working condition are actually safer to use as they can get the dishes to the higher temperatures that kill bacteria.
Do's and don'ts when handling foods that can support the growth of bacteria
Do:
* Wash your hands often with soap:
* after using the washroom
* dealing with refuse and the refuse pail
* after a sneeze
* between working with different types of foods
* touching a pet
* touching your mouth or nose or a sore with your fingertips
* Throw out chipped or damaged plates or utensils.
* Wash, rinse, and wipe your dishes thoroughly.
* Wash fruit and vegetables that have been on display uncovered at the grocery store. It is possible that it could have been handled or touched by hundreds of people. Worse yet, it may have been sneezed on.
* Keep the utensils or dishes that you use for your pet separate.
* Except for fresh vegetables, cook your food thoroughly.
* Wash working surfaces often.
* Cool food quickly and keep it cold until it's ready to be reheated or served.
* Cook left-over foods for as long as possible.
Don't:
* Reheat leftovers more than once.
* Keep food on hold.
* Freeze food more than once. Once it thaws, use it.
* Use the same dish rag or tea towel to clean up for a different meal.
* Cook meats that are even a little bit frozen. Thaw thoroughly first because the center of the food may not be thoroughly cooked when the outside is, if it was cooked frozen.
* Return a tasting spoon into the food you are cooking.
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