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Fresh Coffee Company A Grading

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3 French Hens A Grading

Café Destiny A Grading

Charlie’s Café A Grading

Cambroudi’s Café A Grading


Nutrient Agar:  

Will grow the largest number of different types of microbes - fungi and bacteria. Yet, not all bacteria can grow on these. Some find it too rich, and others find it deficient.An Introduction to Agar

With its distinctive smell, one can easily distinguish agar from the other materials commonly found in a laboratory. Chemically, agar is a polymer made up of subunits of the sugar galactose, and is a component of the cell walls of several species of red algae that are usually harvested in eastern Asia and California. Dissolved in boiling water and cooled, laboratory agar looks gelatinous. Although agar's chief use is as a culture medium for various microorganisms, particularly for bacteria, its other less well-known uses include serving as a thickening for soups and sauces, in jellies and ice cream, in cosmetics, for clarifying beverages, and for sizing fabrics.(1)

One might ask why agar, as opposed to regular gelatin (like that found in Jelly), is used for culturing bacteria. The answer is agar, unlike gelatin, won't be degraded (eaten) by bacteria. Also, agar is firmer and stronger than gelatin. It's still possible, however, to use gelatin as a culture medium for bacteria if agar is unavailable.(2)

The Difco& BBL Manual gives more details about agar and its usage:(3)

Agar is a phycocolloid extracted from a group of red-purple marine algae (Class Rhodophyceae) including Gelidium, Pterocladia and Gracilaria. Gelidium is the preferred source for agars. Impurities, debris, minerals and pigment are reduced to specified levels during manufacture.

 

Agar is a gel at room temperature, remaining firm at temperature as high as 65°C. Agar melts at approximately 85°C, a different temperature from that at which it solidifies, 32-40°C. This property is known as hysteresis. Agar is generally resistant to shear forces; however, different agars may have different gel strengths or degrees of stiffness.

 

Agar is typically used in a final concentration of 1-2% for solidifying culture media. Smaller quantities (0.05-0.5%) are used in media for motility studies (0.5% w/v) and for growth of anaerobes (0.1%) and microaerophiles.

 

Specifications for bacteriological grade agar include good clarity, controlled gelation temperature, controlled melting temperature, good diffusion characteristics, absence of toxic bacterial inhibitors and relative absence of metabolically useful minerals and compounds.

A large class of plants, commonly called red algae, coextensive with the division Rhodophycota. Most red algae are found in the ocean, growing on rocks, wood, other plants, or animals in the intertidal zone and to depths limited by the availability of light. A few genera and species occur in fresh water, and these are usually found in rapidly flowing, well-aerated, cold streams. Some, however, grow in quiet warm water, while a few are subaerial. Most red algae are photosynthetic, but some grow on other algae with varying degrees of parasitism. Approximately 675 genera and 4100 species are recognized. See alsoAlgae.

 

http://www.sciencebuddies.org/science-fair-projects/project_ideas/MicroBio_Agar.shtml

http://www.answers.com/topic/rhodophyceae-1?cat=technology

 

Classification of Bacteria

Until recently classification was done on the basis of such traits as:

        shape

            bacilli: rod-shaped

            cocci: spherical

            spirilla: curved walls

        ability to form spores

        method of energy production (glycolysis for anaerobes, cellular respiration for aerobes

        nutritional requirements

reaction to the Gram stain.

http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/E/Eubacteria.html

 



http://www.cfsan.fda.gov/~dms/a2z-b3.gif

Agar Petri Dishes

        1 Petri dish (4 inch size)

        Water

        Agar nutrient (5 grams)

        Container to boil water

        Plastic wrap

        Cotton swab

        Hand sanitizer

 

You'll need a clean, microwave-safe container (quart-size bowl works great) to mix and heat the agar with water. These mixing proportions make enough nutrient agar to prepare two halves of the Petri dish. Mix 1/2 teaspoon agar (about 1.2 grams) with 1/4 cup (60 mL) of hot water and stir. Bring this mixture to a boil for one minute to completely dissolve the agar. CAUTION: Adult supervision is required to boil water. If you are using the microwave oven to boil the mixture, be careful not to let the solution boil over. The mixture should be clear “ no particles floating around in the solution. Allow the mixture to cool for 3 to 5 minutes before moving onto the next step.

 
Carefully pour equal amounts of the warm agar nutrient solution into both halves of the Petri dish. Loosely cover each Petri dish with plastic wrap and allow the solution to cool and harden for at least an hour.

It's time to collect some bacteria on the end of a cotton swab. The classic test is to roll a clean cotton swab in your mouth and then to lightly draw a squiggle with it on the gelled agar. However, many people like to test something even more gross like the keys on your computer or the television remote control. Unless someone recently cleaned the buttons on the TV remote, you're in for some real YUCK in a few days.

         
Since you poured agar into each half of the Petri dish, you have two places to grow bacteria. Consider all of your options below (or come up with your own) to collect samples. You might want to collect a sample from a computer keyboard for one half of the Petri dish and collect a sample from a door handle for the other half. Remember, you must use clean cotton swabs for each sample. In order to get a good sample collection, dampen the end of the cotton swab with water. Be sure to wipe the end of the cotton swab all over the surface to be test. Cover the end of the swab with invisible bacteria! Things that you might want to test Door handles, your hands, under your fingernails, your mouth, the top of a desk, computer keyboard, remote control, pencil or a pen, area around a bathroom sink, fax machine, calculator or your favorite toy.

Pull the plastic wrap covering away from the Petri dish and LIGHTLY draw a squiggly line in the agar with the end of the cotton swab. Cover the Petri dish with plastic wrap, use a piece of paper or tape to label the dish
with the name of the item you tested and place the Petri dish in a safe, dark place to let the bacteria grow.

Here's a clever test try placing a drop (no more) of hand sanitizing gel in the middle of one of your squiggles. Your hypothesis might be that the antibacterial chemical in hand sanitizer will keep any bacteria from growing. We'll see if you're right.

Cover the Petri dish with plastic wrap, use a piece of paper or tape to label the dish with the name of the item you tested. Place the plates in a warm dark place to grow - not too warm, but anything up to about 98 degrees F (37 degrees C) should be fine. In a short time, you'll be greeted by an amazing variety of bacteria, molds, and fungi. You should continue to see more and larger colonies for the next few days, but you should not see any growth where the disinfectants (hand sanitizers) are. You might even see a "halo" around each spot where you placed the hand sanitizer. This halo is called the "kill zone" - measure and compare the size of the kill zone to determine effectiveness of different antibacterial agents.

http://www.stevespanglerscience.com/content/experiment/00000165

Bacteria (singular: bacterium) are unicellular microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods to spirals. Bacteria are ubiquitous in every habitat on Earth, growing in soil, acidic hot springs, radioactive waste,[1] seawater, and deep in the Earth's crust. There are typically 40 million bacterial cells in a gram of soil and a million bacterial cells in a millilitre of fresh water; in all, there are approximately five nonillion (5×1030) bacteria on Earth,[2] forming much of the world's biomass.[3] Bacteria are vital in recycling nutrients, and many important steps in nutrient cycles depend on bacteria, such as the fixation of nitrogen from the atmosphere. However, most of these bacteria have not been characterized, and only about half of the phyla of bacteria have species that can be cultured in the laboratory.[4] The study of bacteria is known as bacteriology, a branch of microbiology.

http://en.wikipedia.org/wiki/Bacteria

GROSS!

Studies show that kids touch their faces every 3 minutes. You could get very ill from eatin            g at a dirty restaurant table.

Did you know?  Studies show that:

90% of mums are concerned about germs that their children encounter in public.

Cleanliness is one of the top 3 factors that people use to decide where to dine out?

4 out of 5 illnesses are spread by touch.

The average restaurant table contains more germs per square inch than  changing tables, elevator buttons, or shopping cart handles.

http://www.xel.com/articles/Surface-Testing-Reveals-Restaurant-Tables.htm