Exercise 5: Antimicrobial Action of Spices

Exercise 5: Antimicrobial Action of Spices

Food can be a significant mechanism for disease transmission. The Center for Disease Control (CDC) in Atlanta, GA estimates that each year 76 million people in the United States become sick, 300,000 are hospitalized, and 5,000 people die from food borne illnesses.

Foodborne illnesses usually result when pathogenic bacteria are introduced during the processing or preparation of food. Symptoms of food borne illnesses may vary from an upset stomach to more serious symptoms, including diarrhea, vomiting, abdominal cramps, and severe dehydration.

Bacteria occurring in the environment may lead to food contamination, which can take place during growing, harvesting, storing, shipping, or final preparation of food products. People that handle food can transmit opportunistic pathogens associated with the human body, like Staphylococcus aureus, because of unsanitary practices such as failure to wash their hands. Most cases of foodborne illnesses can be prevented through proper cooking and handling of food, which kills bacteria.

Bacteria are naturally associated with some foods and these bacteria are not necessarily harmful to humans. The chalky appearance of grapes is due to yeasts that are naturally associated with grapes as well as many other fruits. When certain crops are harvested, such as potatoes and green beans, they will have soil bacteria associated with them. If these foods are frozen, both the food as well as any associated bacteria will also be preserved.

Certain foods have high numbers of bacteria associated with them because microorganisms are used in their production. Yogurt, sauerkraut, and summer sausage are examples of foods that may have high numbers of bacteria.

Many bacteria in meat are harmless, but certain strains of Escherichia coli are found in the intestines of cattle and can become associated with meat if contamination occurs during the butchering process. Hamburger meat may have high counts of bacteria which can be introduced during the meat grinding process. Serious foodborne illnesses result from eating improperly cooked hamburger because the meat must be heated long enough, and at a high enough temperature, to kill any harmful bacteria.

Transmission of this pathogen can also occur when fecal matter of cattle contaminates fruits and vegetables. Both lettuce and spinach have been recalled in recent history due to concerns over E. coli contamination.

Bacteria can easily spread from one food product to another in the kitchen by contacting cutting boards, sponges, knives, and countertops. The easiest way to prevent food borne illness is to properly handle and cook foods. This not only includes cooking meat thoroughly, but also includes washing your hands and kitchen utensils carefully during the food preparation process.

Food practices have developed over many years to prevent growth of microbes, both bacteria and fungi (mold). Drying, curing, salting, and pickling, for example, create an environment which cannot support microbial growth in foods. People living in warm climates, where food spoils faster, developed cuisines that employ spices and seasonings to retard spoilage.

Spice Lab Report

In this exercise you will attempt to demonstrate the ability of added spices to prevent the growth of mold (fungus) on applesauce.

Materials

(1) One six-pack of applesauce cups, any brand, unsweetened, “natural” style. These cups are typically 4 oz. each. All six cups need to come packaged together. They need to be the same variety with the same expiration date.

(2) Five different types of powdered seasonings; one should be cinnamon. Other suggestions are garlic, paprika, ginger, salt, onion, and curry.

(3) A small measuring spoon, 1/8 tsp. is recommended.

(4) Identify a shelf or location where the cups will not be disturbed or attract vermin (or pets) and away from a fan.

Procedure

Using a six-pack of small applesauce cups, you will set aside one to be used as a control, adding no spices to it. Cinnamon will be added to another cup. You will choose a different powdered spice for the remaining four cups.

All six cups will be left uncovered in the same location for a minimum of one week. They will be observed daily, mold growth will be recorded and photographed.

Leave them in an undisturbed area, one that is not likely to attract insects, wildlife or pets. The cups should be positioned close to each other to make sure that they are exposed to the same conditions.

The amount of spice that you add needs to be identical for each cup and you must thoroughly stir each with a clean utensil.

(1) Label each applesauce cup, numbered 1-6.

(2) Remove the cover from each and discard.

(3) Stir 1/8 tsp. of a different powdered spice into each of five applesauce cups.

(4) The control cup of applesauce, with no spice added, should also be stirred.

(5) Use a clean spoon or coffee stirrer for each cup.

(6) Put all six cups in the same location.

(7) Check them daily for growth.

(8) Photographs will be required for the appearance of the cups on days 1, 4 and 7.

What to Submit – All submissions should be single Word documents.

(1) An introduction describing the spices and applesauce that you selected and the location that you left the cups during the study.

(2) Any unforeseen complications.

(3) Photographs of all six cups, clearly labeled, taken on the first, fourth, and seventh day of the study.

(4) Points will be deducted if I cannot easily read the legends of the photographs; I need to know which treatment (spice) each cup represents.

Photographs need to be embedded as images into your Word document. Your photo ID needs to be placed next to the cups in the pictures.

(5) Your conclusions. What did you learn from this study?

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