(FBIC) Effects of Ingredients on Microbes, Processing Time and Temperature Lesson

Effects of Ingredients on Microbes, Processing Time and Temperature

Microorganisms are all around us, and they are capable of surviving in a wide array of environmental conditions.  They are a necessary part of our world and perform a variety of useful functions. Some microorganisms are harmful and cause disease while others are benevolent, neutral or even helpful.  Some help us to produce certain foods, break down toxins in our environment, while others can kill us.  

Have you ever checked to see how many foods you can find that contain microorganisms or were produced with the help of microorganisms? The chart below displays some common microbes found in foods and an indication of whether each item needs special handling such as refrigeration to keep from spoiling.

Common Microbes

Food Items	Microbe Responsible	Does this food product need special handling?
Cheddar cheese, swiss cheese, feta, sour cream, buttermilk, yogurt, vinegar	Bacteria	-Refrigerate all cheese between 35-40 degrees Fahrenheit in its original wrapping and in a drawer. -Store yogurt in the refrigerator in its original sealed container. -The safest container to store vinegar is a glass.   Store it in a cool and dark place for around 6 months.
Blue cheese, mushrooms	Fungi	-Prepackaged mushrooms should stay in a package but loose mushrooms should be stored in a paper bag or in a cloth bag in the refrigerator. -Blue cheese should be wrapped in plastic wrap or foil after its opened.
Ice cream, salad dressings	Algae	-Ice cream should not be repeatedly softened and refrozen.   It should be in the main part of the freezer between -5 and 0 degrees Fahrenheit. -Salad dressings are best stored in the refrigerator after opening.   Changes in temperature can cause dressings to spoil sooner.   Many oil based dressings like Italian do not require refrigeration.
Bread, other dough products	Yeast	-Bread can be stored in a bread box, plastic or frozen for longer storage. -Dough can be refrigerated for up to two days covered with foil or plastic to prevent from drying out.

Food Preservation Techniques

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

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

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

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

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

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

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

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

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

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

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

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