HAND WASHINGHAND WASHING

When was the last time you washed your When was the last time you washed your hands?hands?

What have you done since the last time?What have you done since the last time?

For the next two minutes discuss with your For the next two minutes discuss with your science group all you know about hand science group all you know about hand washing.washing.

Why should a person wash their hands?

How does hand washing affect microbes?

Can the microbes on your hands have a serious effect on your personal health?

How frequently should a person wash their hands?

How will your hand washing habits change?

Hand washing is the easiest way to prevent the spread of diseases and infection.

Studies have found that only 68% of Americans wash their hands after using the restroom.

There are millions of microbes on your hands. Many are harmless, but some are disease causing.

Hand washing with plain soaps suspends the microbes and allows them to be rinsed off.

Antibacterial soaps inhibit the growth of microbes.

Many studies have found that washing hands with soap and vigorous rubbing for as long as it takes you to sing Happy Birthday is the very effective in removing harmful bacteria.

Let’s Check Your Hands!Let’s Check Your Hands!

What is the method used to discover the What is the method used to discover the wonders in science that we have today?wonders in science that we have today?

Scientific MethodScientific MethodThe five steps are:The five steps are:QuestionQuestionStudy/HypothesisStudy/HypothesisExperimentExperimentCollect DataCollect DataConclusionConclusion***It is important to use only one ***It is important to use only one variablevariable when when

conducting an experiment.conducting an experiment.

DID YOU KNOW?DID YOU KNOW?

Seconds after you were born, tiny Seconds after you were born, tiny organisms surrounded and invaded your organisms surrounded and invaded your body.body.Millions of these organisms coat your skin.Millions of these organisms coat your skin.As you sit in your desk listening to this As you sit in your desk listening to this presentation, they swarm inside your presentation, they swarm inside your nose, throat, and mouth.nose, throat, and mouth.There are more of these organisms living There are more of these organisms living in your mouth than there are people who in your mouth than there are people who are living on Earth.are living on Earth.

The human body has The human body has more bacteria than more bacteria than

it has cells. An it has cells. An unborn baby is unborn baby is

completely free of completely free of bacteria, but the bacteria, but the instant they are instant they are

born they acquire born they acquire billions of bacteria. billions of bacteria.

Bacteria are Bacteria are essential for a essential for a healthy body.healthy body.

www.pregnancy-leads-to-new-babies.com/ images/

BacteriumBacteriumMicroscopicMicroscopic

Living and contains DNALiving and contains DNA

Live on earth- in Live on earth- in soil, air, water, plants, soil, air, water, plants, animals animals andand people. people.

Bacteria (plural form)Bacteria (plural form)

Group together in colonies (clusters or Group together in colonies (clusters or chains)chains)

Some help humans digest food and Some help humans digest food and protect against harmful bacteria.protect against harmful bacteria.

There are more than 10,000 kinds of There are more than 10,000 kinds of bacteria and an unknown number bacteria and an unknown number

still waiting to be discovered.still waiting to be discovered.

www.elements-of-design.net/

BACTERIA INFORMATIONBACTERIA INFORMATIONBacteria are classified Bacteria are classified into three groups into three groups according to their according to their shape: shape: roundround (cocci (cocci {kŏk‘sí}{kŏk‘sí}), ), spiralspiral (spirilla (spirilla {spí-rĭl'ə}{spí-rĭl'ə}), ), and and rodrod (bacilli (bacilli {bə-sĭlỉ}{bə-sĭlỉ}) ) shape. shape. Some round shape bacteria can Some round shape bacteria can

cause infections in people. cause infections in people. Some spiral shape bacteria are Some spiral shape bacteria are

used to make cheese. used to make cheese. Some rod shaped bacteria have Some rod shaped bacteria have

been known to cause food been known to cause food poisoning. poisoning.

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www.redcolony.com/ pics/content/bacteria.jpg

io.uwinnipeg.ca/.../ 27-03c-HelicalProkaryote.jpg

Bacteria MultiplicationBacteria Multiplication

Sexual reproductionSexual reproduction Two parentsTwo parents ConjugationConjugation (transfer of genetic material (transfer of genetic material

through bridge)through bridge)

Asexual reproductionAsexual reproduction Binary FissionBinary Fission - Simply splitting in two - Simply splitting in two

Bacteria are so small that about Bacteria are so small that about 1,000 could fit on the head of a 1,000 could fit on the head of a

pin. pin.

www.agen.ufl.edu

More on GrowthMore on Growth

Rapid reproduction, as Rapid reproduction, as fast as once every 20 fast as once every 20 minutesminutes

Continues until they run Continues until they run out of the basicsout of the basics

FoodFood AirAir SpaceSpace

Thrive in warm, damp Thrive in warm, damp places (e.g. human body, places (e.g. human body, uncovered food) uncovered food)

SURVIVAL NEEDSSURVIVAL NEEDSObtaining foodObtaining food AutotrophsAutotrophs-Make their own food-Make their own food

Some make food by capturing and using the sun’s Some make food by capturing and using the sun’s energy as plants do.energy as plants do.

Some use energy from chemical substances in Some use energy from chemical substances in their environment to make food.their environment to make food.

HeterotrophsHeterotrophs-Obtain food by consuming -Obtain food by consuming autotrophs or other heterotrophsautotrophs or other heterotrophs

Heterotrophic bacteria may consume a variety of Heterotrophic bacteria may consume a variety of foods- from milk and meat to decaying leaves on a foods- from milk and meat to decaying leaves on a forest floor. forest floor.

Respiration-bacteria need a constant Respiration-bacteria need a constant supply of energy to carry out their supply of energy to carry out their functions. This energy comes from food. functions. This energy comes from food.

The process of breaking down food The process of breaking down food to release its energy is call respiration.to release its energy is call respiration.

SURVIVAL NEEDS CONTINUEDSURVIVAL NEEDS CONTINUED

MOVEMENTMOVEMENT

The typical bacterial cell has The typical bacterial cell has flagellumflagellum (plural for (plural for flagella.) They may have many, one, or none.flagella.) They may have many, one, or none.

A A flagellumflagellum is a long, is a long, whipwhip like structure that like structure that extends from the cell wall and helps the extends from the cell wall and helps the bacterium move by spinning like a propeller.bacterium move by spinning like a propeller.

Most bacteria that do not have flagella cannot Most bacteria that do not have flagella cannot move on their own. Instead they depend on air, move on their own. Instead they depend on air, water currents, clothing, and other objects to water currents, clothing, and other objects to carry them from one place to another.carry them from one place to another.

PREVENTING HARMFUL BACTERIAPREVENTING HARMFUL BACTERIA

Food manufacturers use a variety of methods to Food manufacturers use a variety of methods to prevent harmful microbes from infecting foods.prevent harmful microbes from infecting foods. Heating or cooling will affect the number of bacteria Heating or cooling will affect the number of bacteria

that can grow in it.that can grow in it.Boiling liquids at high temperatures destroys microbes.Boiling liquids at high temperatures destroys microbes.

Freezing food makes it too cold for microbes to grow quickly.Freezing food makes it too cold for microbes to grow quickly. Six ways to control the growth of bacteria in foods Six ways to control the growth of bacteria in foods

are:are:PasteurizationPasteurizationDryingDryingRefrigerationRefrigeration

FreezingFreezingDehydrationDehydrationVacuum-packVacuum-pack

Pasteurization is a heating process to kill bacteria in foods.

Canning Canning first destroys bacteria through heating and then first destroys bacteria through heating and then the food is placed in a sterilized container and sealed.the food is placed in a sterilized container and sealed.

Drying Drying removes water from the food that bacteria need to removes water from the food that bacteria need to grow and reproduce.grow and reproduce.

Freezing Freezing slows down the spoilage process by changing slows down the spoilage process by changing water into ice; a form that the bacteria cannot use.water into ice; a form that the bacteria cannot use.

Pasteurization Pasteurization destroys most of the existing spoilage destroys most of the existing spoilage organisms by heating the food to a high temperature for a organisms by heating the food to a high temperature for a short duration.short duration.

Pickling or fermentation Pickling or fermentation (culturing) leaves the food with a (culturing) leaves the food with a higher level of acid, making it an inhospitable environment higher level of acid, making it an inhospitable environment for spoilage bacteria.for spoilage bacteria.

UHT UHT ((ultra-high temperature) uses heat higher than ultra-high temperature) uses heat higher than pasteurization: then pressure is applied resulting in a sterile pasteurization: then pressure is applied resulting in a sterile product.product.

Vacuum packaging Vacuum packaging uses a vacuum sealed, abrasion-uses a vacuum sealed, abrasion-resistant moisture-impermeable film that inhibits molds, resistant moisture-impermeable film that inhibits molds, yeasts, and bacterial growth on the surface of the things yeasts, and bacterial growth on the surface of the things such as meat. Since there is no air in the package, vacuum-such as meat. Since there is no air in the package, vacuum-packaged meat will have a darker, purple color before packaged meat will have a darker, purple color before being opened. Once the meat is exposed to oxygen, it will being opened. Once the meat is exposed to oxygen, it will turn the familiar bright red color, because of the natural turn the familiar bright red color, because of the natural reactions within the package. Fresh vacuum-packaged meat reactions within the package. Fresh vacuum-packaged meat will give off a slight odor when opened. The smell will will give off a slight odor when opened. The smell will dissipate within a few minutes. This should not be dissipate within a few minutes. This should not be confused with spoilage.confused with spoilage.

Smoking Smoking adds smoke-born chemicals to food that help adds smoke-born chemicals to food that help destroy potential spoilage organisms.destroy potential spoilage organisms.

Chemical additives Chemical additives are designed to destroy spoilage are designed to destroy spoilage organisms or inhibit their growth. Sugar and salt are organisms or inhibit their growth. Sugar and salt are examples of additives that have been in use for centuries. examples of additives that have been in use for centuries. Both of these work by drawing water out of the spoilage Both of these work by drawing water out of the spoilage organisms, thus preventing their growth.organisms, thus preventing their growth.

Irradiation Irradiation is a process that pasteurizes food by using is a process that pasteurizes food by using energy, just like milk is pasteurized using heat. Irradiation energy, just like milk is pasteurized using heat. Irradiation DOES NOT make food radioactive. The food never DOES NOT make food radioactive. The food never touches a radioactive substance. Irradiation destroys touches a radioactive substance. Irradiation destroys insects, fungi, and bacteria. Fewer nutrients are lost during insects, fungi, and bacteria. Fewer nutrients are lost during irradiation than in cooking and freezing. Food irradiation irradiation than in cooking and freezing. Food irradiation has been approved in 37 countries for more than 40 has been approved in 37 countries for more than 40 products. Astronauts have eaten irradiated foods for years.products. Astronauts have eaten irradiated foods for years.

Food additives Food additives are any substances added to food. Sugar, are any substances added to food. Sugar, salt, and corn syrup are the most commonly used food salt, and corn syrup are the most commonly used food additives. Food additives keep foods fresh, slow microbial additives. Food additives keep foods fresh, slow microbial growth, give desired texture and appearance, and aid in growth, give desired texture and appearance, and aid in processing and preparation.processing and preparation.

HELPFUL BACTERIAHELPFUL BACTERIA

FOODFOOD Cheese, yogurt, apple cider, sour creamCheese, yogurt, apple cider, sour cream

Environmental recycling Environmental recycling Bacteria that lives in the soil are Bacteria that lives in the soil are decomposersdecomposers

Organisms that break down large chemicals in dead organisms into small Organisms that break down large chemicals in dead organisms into small chemicals.chemicals.

Environmental CleanupEnvironmental Cleanup Some bacteria are used to convert the dangerous chemicals in an oil Some bacteria are used to convert the dangerous chemicals in an oil

spill into harmless substances.spill into harmless substances.Health and Medicine and preventioHealth and Medicine and preventio

Washing your hands, washing and protecting open wounds, and staying Washing your hands, washing and protecting open wounds, and staying healthy by exercisinghealthy by exercising are, ways to prevent bacteria from entering your are, ways to prevent bacteria from entering your body.body.

Vaccines are a Vaccines are a weakened form of the diseaseweakened form of the disease that are that are injected injected into a into a person.person. The The person’s bodyperson’s body then then makes antibodies to prevent the actual makes antibodies to prevent the actual disease.disease.

Diseases Caused by BacteriaDiseases Caused by Bacteria

Strep ThroatStrep Throat

Tooth DecayTooth Decay

E coliE coli

PlaguePlague

TetanusTetanus

AnthraxAnthrax