Presentation on theme: "Microbes, Foodborne Illness, and Food Preservation"— Presentation transcript:
1 Microbes, Foodborne Illness, and Food Preservation
2 Food Spoilage Foodborne Illness How do Microbes Affect Us?Food SpoilageFoodborne Illness
3 What is Food Spoilage?Microbes in food can cause the food to spoil (rot)Microbes cause millions of dollars of food to spoil each year
4 What is Foodborne Illness? What is it?A disease caused by consuming contaminated foods or beveragesContamination caused by bacteria or virusPathogen-harmful bacteria that can cause disease
5 What’s the Problem?Some microbes make us sick when we eat them. You can’t see these microbes!!!!!!The greatest dangers are microbes that produce toxins and causes human illness!
6 Is Foodborne Illness a Big Problem? Over 76 million Americans get sick from foodborne microbes each year!About 5,000 Americans die from foodborne illness each year.
7 What Happens? Microbes pass from stomach to intestines Microbes attach to intestine wall and prevent water from being absorbed, or nutrients from being absorbedCertain microbes release a toxin that will enter the bloodstream and travel through the entire bodyUp to 5000 people die every year
8 SymptomsRange from mild stomach & intestine problems to DEATH, includingUpset StomachAbdominal CrampsNausea and vomitingDiarrheaFeverDehydration
9 How Does Food get Contaminated? Food is exposed to pathogens-When grown or raised1. animals have pathogensin intestines already2. vegetables grown in dirtysoil, or watered with contaminated water-In factory or Slaughter House1. meat exposed to pathogens from other meats
10 Example of Bacteria in Food Bacteria naturally living in milk will spoil milk in two or three hours if left at room temperature.Putting milk in the refrigerator doesn’t kill bacteria already there, but it slows down the bacteria enough that the milk will stay fresh for a week or two.
11 How does Food get Contaminated? By humans in their own kitchen1. Poor hygiene2. Using used dirty utensils3. Using an old cutting board4. Not washing your counters5. Leaving food out of refrigerator6. Not washing food
12 How can we Prevent Foodborne Illnesses? 1. Proper Hygiene and Handling of Food to keep pathogens away2. Food Preservation Methods to keep food from spoiling
13 Why Does Preserving Food Help? The basic idea - food preservation either:Slows down the activity of disease-causing bacteriaKills the bacteria altogether
14 Is Food Preservation New? Food preservation is one of the oldest technologies used by human beings.Some food preservation methods have been around for thousands of years (e.g. pickling and sun-drying), while others are more modern (e.g. pasteurization and irradiation).
15 What is “sterile”? A food that is sterile contains no bacteria. Unless sterilized and sealed, all food contains bacteria.
16 How Does This Work?We preserve food by changing the environment that the food is in (e.g. changing the temperature, oxygen, pH or by removing water).
17 Can you think of the different ways that food is preserved?
18 Common Food Preservation Methods Include: Refrigeration and freezingCanningDehydration (Drying Food)Freeze-DryingSaltingPicklingPasteurizationFermentationChemical PreservationIrradiation
21 Refrigeration and Freezing Refrigeration and freezing are the most popular forms of food preservation in use today.Refrigeration = 32 ° F to 40 ° FFreezing = below 32° F
22 Refrigeration and Freezing a. Refrigeration slows the growth of bacteria1. bacteria is less active, but they are not killed2. Food will still eventually spoil in timeb. Freezing kills bacteria or cause it to become completely inactive
23 Canning Food -Used since 1825 =Food can be stored for long periods of timeb. Process1. Food is heated to a temperature that kills all bacteria2. Container is sealed to prevent new bacteria from getting to foodc. Can be in any sealable container1. Milk cartons, fruits in jars, vegetables in cans
24 CanningOnce you open the can, bacteria enter and begin attacking the food, so you have to "refrigerate the contents after opening"
25 DryingEvidence shows that Middle East and oriental cultures actively dried foods in the hot sun as early as 12,000 B.C..Drying removes water from the food. Since most bacteria die or become inactive when dried, dried foods kept in air-tight containers can last quite a long time.
26 Drying (Dehydration) a. Food can be stored for long periods of time b. Drying removes water from food1. Bacteria grown in moist environmentsc. Process uses fans and high temperatures to dry the foodd. Examples1. beef jerky, powdered milk, pasta, instant rice, fruit chips
28 Salting salt causes the moisture to come out of the food Eliminates water so bacteria can’t livb. one of oldest preservation method
29 Pasteurizationa. Food is heated to high temperature for a short time at °F to kill all microbesb. Used on milk and juicesc. Food must be refrigerated after pasteurization
30 Food IrradiationFood is sterilized by using energy in the form of radiation1. Does NOT make food radioactiveMicrobes are killed by radiationc. Used on fruit and vegetables1. Kills insects, fungi, andbacteria2. Delays ripening so food can be shipped
31 IrradiationIrradiation DOES NOT make food radioactive. The food never touches a radioactive substance. Irradiation destroys insects, fungi, and bacteria.
32 Vacuum Packing Air is removed from package before it is sealed b. Without oxygen, bacteria and mold can not grow
34 Pickling a. Acidic environments prevent the growth of bacteria. b. Usually uses vinegar, salt water, or an alcohol to preserve foodc. Will drastically change the flavor of food so is not good for all types of food
35 Pickling or Fermentation These leave food with a higher level of acid, making it an inhospitable environment for spoilage bacteria.
36 2. Fermentationa. encourages growth of “good” bacteria and prevent growth of “bad” bacteria b. Examples of fermented food: 1. bread, yogurt, wine, cheese, soy sauce c. Foods must be refrigerated
37 FermentationFermentation refers to the activity of bacteria and fungi.These microbes break food molecules into simple substances.
38 Smoked FoodsSmoking adds chemicals from smoke to food that help destroy potential spoilage organisms.
39 3. Smoking a. Used to preserve meats 1. Heat Kills bacteria 2. chemicals from smoke kill microbes3. Outer surface of meat is dried removing moisture
40 Food PreservativesIf you look at the ingredient labels of different foods, you will see different types of chemicals used.All of these chemicals either prevent the activity of bacteria or kill the bacteria.
41 Pancake syrup can sit out because of the ingredients it contains.
42 Chemical Preservation There are three classes of chemical preservatives commonly used in foods:Benzoates (such as sodium benzoate)Nitrites (such as sodium nitrite)Sulphites (such as sulphur dioxide)