Light exposure could result in color and vitamin loss. Light also may be responsible for the oxidation of fats. These creatures require food to survive and damage food, making it more vulnerable to further deterioration. Bruises and cracks on raw produce leave areas where microorganisms easily may grow.
Improperly packaged foods, dented cans and broken packages provide places for microorganisms, air, light and creatures to enter. Gentle handling of food items will help maintain food quality and safety longer. Temperature affects storage time, and food deteriorates faster at higher temperatures. Recommended temperatures for storage areas are:. Microorganisms, both spoilage and pathogenic, grow rapidly at room temperature.
An external thermometer will let you keep tabs on the fridge or freezer temperatures without opening the doors. Bacteria need moisture, oxygen and the proper temperature range in order to multiply. Dehydration is the process of removing moisture from foods, thereby slowing or stopping the growth of spoilage bacteria.
To dehydrate food properly, you need low humidity and a source of heat. You can use a conventional oven set to warm with the door open or an actual food dehydrator. The food needs to be heated to about F. Dry, circulating air helps draw moisture out of the food. Dehydration also makes foods lighter, smaller and easier to store and transport. You can preserve high-acid foods using a traditional process called canning.
Apples, berries, peaches and tomatoes are just a few foods that may be canned safely. Boiling water kills spoilage bacteria and creates a vacuum seal around the jar lid. Canned food items must be cooked for a minimum amount of time to ensure that all bacteria are killed. Welcome, Blair! Rotten food definitely is nasty! We must be sure not to waste food and always dispose of it properly to try and avoid this problem.
Thanks for sharing! Hi Charlesthompson! You're right. When we don't eat food and don't dispose of food, it can rot. Then it's a nasty thing to clean up! Thanks for commenting! We are undergoing some spring clearing site maintenance and need to temporarily disable the commenting feature. Thanks for your patience. Drag a word to its definition. You have answered 0 of 3 questions correctly and your score is:. Want to add a little wonder to your website?
Help spread the wonder of families learning together. We sent you SMS, for complete subscription please reply. Follow Twitter Instagram Facebook. Why does food rot? What is photodegradation? How can you prevent food from spoiling? Tags: See All Tags chemical , decay , enzyme , food , light , microbial , microorganism , moisture , mold , oxygen , photodegradation , preservative , reaction , rotten , science , smell , souring , spoilage , taste , temperature , yeast. Wonder What's Next? Keep learning even more when you check out the following activities with a friend or family member: Ready for a field trip?
Ask an adult friend or family member to take you on a field trip to a local grocery store. These workers have to be very familiar with food freshness. What steps do they take to make sure that all food sold is fresh and healthy? Do they ever have problems with food rotting? What do they do with rotten food? How do you keep food from rotting at your house?
Talk with an adult friend or family member about the steps they take to ensure that all food is kept as fresh and as safe as possible. What are some of the methods used? Which are most effective? Which foods tend to rot fastest and need to be replaced most often? Up for a challenge? Try this interesting Rotting Food science experiment! You'll need a clear jar with a lid and a few basic foods, including cheese, bread, fruit, and vegetables. Be sure to follow the directions carefully.
You'll probably want help from an adult friend or family member, too. Which food do you think will rot fastest? Did your experiment prove your guess to be correct or not?
Did you get it? Test your knowledge. Wonder Words mold yeast borne fuel seed battle enzyme decay nutrient tactic environment inhibit percentage deterioration microorganism photodegradation refrigerating preservative Take the Wonder Word Challenge.
Join the Discussion. Love the info. Jan 16, Dec 17, It is interesting. Thanks for sharing, storm! Dec 9, You're welcome, skylee! How are you using Wonderopolis today? Angela cox Nov 10, Nov 10, You're welcome, Angela! Nov 5, We're glad you like it, lottie! Soil is a particularly rich source of Clostridium bacteria. Water may be contaminated by faeces. Plants may also be contaminated by faeces if untreated sewage has been used as a fertiliser. The intestines of all humans and animals are full of microorganisms, some of which are beneficial but others are pathogenic.
Bacterial pathogens such as Salmonella, Campylobacter and Escherichia coli strain OH7 are common examples. Contamination of foods by faecal material is the major cause of food poisoning events. Escherichia coli abbreviated to E.
The strain called E. Many foodborne microorganisms are present in h ealthy animals raised for food, usually in their int estines, hides, feathers, etc. Meat and poultry carcasses can be contaminated during slaughter by contact with small amounts of intestinal contents. Animal hides are an important source of contamination of the general environment, the hands of meat worker s, and skinned meat carcasses.
Hides are a primary source of E. Hides become contaminated either because the outside of the hide is dirty, or because once removed from the animal, the inside of the hide is a good breeding place for microorganisms. Animal feeds are a source of microorganisms, especially Salmonella , which can contaminate poultry and other farm animals. The organisms in dry animal feed spread throughout the local environment and may get on to animal hides, hair and feathers, as well as on people who handle the feeds.
The term food handler can be applied to anyone who touches or handles food, and this includes people who process, transport, prepare, cook and serve food. The microorganisms transmitted to foods by food handlers may come from the hides of animals, soil, water, dust, gastrointestinal tracts and other environmental sources.
In food preparation at home, foodborne microorganisms can be introduced from the unwashed hands of people who are infected by bacteria and viruses, and who cook and serve the food to family members. Food utensils are cutting boards, knives, spoons, bowls and other equipment used in food preparation, which may become contaminated during food processing and preparation.
For example, in families where there is no access to running water, the food utensils may not be properly cleaned, stored and handled, and may become a major route of food contamination. Cross-contamination of food is the transfer of harmful microorganisms between food items and food contact surfaces. Prepared food, utensils and surfaces may become contaminated by raw food products and microorganisms.
These can be transferred from one food to another by using the same knife, cutting board or other utensil without washing it between uses.
A food that is fully cooked can become re-contaminated if it touches raw foods or contaminated surfaces or utensils that contain pathogens. For example, you should never:. An unsafe temperature for food storage is a major factor in food contamination. Many microorganisms need to multiply to a very large number before enough are present in food to cause disease in someone who eats it. However, if bacteria can have warm, moist conditions and an ample supply of nutrients, one bacterium can reproduce by dividing on average every half an hour and can produce 17 million bacteria in 12 hours!
So, if you leave lightly contaminated food out overnight, it will be highly contaminated and infectious by the next day. Poor personal hygiene of food handlers is another major factor in food contamination. The most important contaminants of food are the microorganisms excreted with faeces from the intestinal tract of humans. These pathogens are transferred to the food from faecal matter present on the hands.
We have already mentioned failure to wash hands after visiting a toilet as a source of food contamination. Can you suggest other times when food handlers should wash their hands? Hands should be washed before starting work on preparing food, and after touching any food, surface or equipment that may be contaminated e. Bad personal habits like scratching your hair and nose with your fingers also contributes to food contamination.
Sneezing and coughing spreads contaminants and microorganisms through the air and onto uncovered food, and onto surfaces and hands that can transfer the infectious agents into food.
Foods can be damaged and also contaminated by pests. Many stored grains are lost through the damage done by pests, including termites mist , beetles, locusts, cockroaches , flies and rodents such as rats and mice. Pests can damage and co ntaminate foods in various ways, such as boring into and feeding on the insides of grains, or tunnelling into stems and roots of food plants. For example, weevils cause large losses of stored grains, especially in warm and humid conditions such as in lowland areas of Ethiopia.
Pests also dama ge the protective skin of foods allowing microorganisms to get inside the food and causing it to rot more quickly. Pests can pollute food with their excreta, and with bodies and body fragments when they die. They also transfer microorganisms on to food while walking on it Figure 8. Flies and cockroaches readily move between wastes and foods, transporting microorganisms with them as they go.
You now know that food can be contaminated from sources in the natural environment, people, food preparation surfaces and utensils, raw and uncooked food, animals, pests, and waste material. To prevent contamination, food production and preparation operations need to be carefully controlled.
Attention also needs to be given to possible chemical contamination of food. Food can be contaminated through the misuse or mistaken handling of chemicals, including pesticides, bleach and other cleaning materials. All chemicals detergent, disinfectant, sanitiser used in the food preparation area should be removed before food preparation begins, to prevent any chemical contamination of the food.
Physical contaminants include stones, pieces of glass, and metal. Physical contamination can occur at any stage of the food chain: for example, stones, bones, twigs, pieces of shell or foreign objects can enter food during handling and preparation. These materials should be removed, if possible, for example by sieving or picking out the items with clean fingers. Food spoilage is the process of change in the physical and chemical properties of the food so that it becomes unfit for consumption.
Food spoilage is any undesirable change in food. Most natural foods have a limited life: for example, fish, meat, milk and bread are perishable foods, which means they have a short storage life and they easily spoil. Other foods also decompose eventually, even though they keep for a considerably longer time. The main cause of food spoilage is invasion by microorganisms such as fungi and bacteria.
Microbial spoilage is caused by microorganisms like fungi moulds, yeasts and bacteria. They spoil food by growing in it and producing substances that change the colour, texture and odour of the food. Eventually the food will be unfit for human consumption. When food is covered with a furry growth and becomes soft and smells bad, the spoilage is caused by the growth of moulds and yeasts look back at Figure 8.
Microbial spoilage by moulds and yeasts includes souring of milk, growth of mould on bread and rotting of fruit and vegetables. These organisms are rarely harmful to humans, but bacterial contamination is often more dangerous because the food does not always look bad, even if it is severely infected.
When microorganisms get access to food, they utilise the nutrients found in it and their numbers rapidly increase.
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