LAB 4 MOHAMMAD SYAFIQ BIN ABDULLAH 113569

LAB 4: SOURCES OF CONTAMINATION AND INFECTION

Introduction

     While contamination of dietary supplements is extremely rare, it is helpful to be aware of possible causes so that outbreaks are prevented.

Contamination can occur anywhere in the production cycle. Pesticide residues and heavy metal pollutants can be introduced to botanicals by growers, or they can seep in from a neighbor's field or the groundwater. Soil can be contaminated from previous uses. Bacteria, which have filled every conceivable ecological niche, can infiltrate crops.

Minerals can be contaminated by the chemical processes used to extract them from rocks and ores. Raw materials might be stored in places that previously held chemicals or other undesirable substances. The manufacturing process itself could expose a product to whatever herbs or other materials were previously run through a particular machine.

Manufacturers establish and follow procedures for ensuring that contaminants do not enter the plant in the form of raw materials and are not introduced during processing. Practices such as testing of materials, regular cleaning of machinery, and tracking of materials by lot number are used to ensure purity. Standardized good manufacturing practices (GMPs) also include guidelines for ensuring cleanliness.

The exemplary safety record of dietary supplement products shows that manufacturers have done an excellent job of ensuring that dietary supplements remain uncontaminated.

Objective

To determine the microorganisms in the air and from healthy humans

Result

Microorganisms in ear

Microorganisms in mouth (cough)

    Microorganisms in air    
                                       
                               

microorganisms in hand

Microorganisms in normal breath

Discussion

     Airborne droplet nuclei generated during coughing or sneezing are a potential source of transmission of infection either by direct inhalation or indirectly through contaminated medical devices. Droplets generated from infected respiratory tracts can remain airborne for long periods of time and transmit infections like tuberculosis, respiratory viral illnesses and antibiotic-resistant hospital bacteria. Airborne contamination is mainly derived from the personnel in the operation theatre and their activities. The bacterial count in operation theatre is influenced by the number of individuals present, ventilation and air flow. Exogenous infections of surgical wounds are caused predominantly by Staphylococcus aureus and S. epidermidis is an important pathogen in implant surgery. S. aureus and S. epidermidis are shed into the environment in skin scales of which 106 are shed by an individual each day. Healthy carriers shed few staphylococci.

     Ear wax is composed mostly of dead skin cells and keratin with a small mixture of cerumen, sweat, and oil. Cerumen is secreted from the ceruminous glands located in the first third outer part of the ear canal and is thought to be composed mainly of cholesterol, squalene, wax esters, ceramides, and triglycerides. The cerumen also has antimicrobial properties which can be attributed to its slight acidic pH of 5 and the presence of lysozyme. In normal circumstances, the ear wax is continuously pushed out of the ear canal by the slow migration of the top layer of skin cells from the tympanic membrane towards the outer ear. The ear wax traps any foreign particles and organisms on its way out.

     Current research on ear wax shows that some of the antimicrobial properties of the cerumen can be attributed to the presence of antimicrobial peptides, Human Beta-defensin 1 and Human Beta-defensin 2. Other recent studies have shown that cerumen directly inhibits the growth of Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans, but its effect on the growth of E. coli remains to be determined. Ear infections are often associated with dysfunction or swelling of the Eustachian tubes. The Eustachian tube is the principal portal for the entry and exit of bacterial in the middle ear. During a viral upper respiratory tract infection (i.e. the common cold), inflammation can block the Eustachian tube. As a result the middle ear does not drain properly and the fluid builds up, becoming a breeding ground for bacteria. Additionally, children have larger adenoid glands than adults.

     Frequent coughing usually indicates the presence of a disease. Many viruses and bacteria benefit evolutionarily by causing the host to cough, which helps to spread the disease to new hosts. Most of the time, coughing is caused by a respiratory tract infection but can be triggered by choking, smoking, air pollution, asthma, gastroesophageal reflux disease, post-nasal drip, chronic bronchitis, lung tumors, heart failure and medications such as ACE inhibitors. A cough can be the result of a respiratory tract infection such as the common cold, pneumonia, pertussis, or tuberculosis. Infections in the breathing tubes can be caused by both bacteria and viruses, although the most common cause in children is a virus.

     A normal breathing rate is approximately 12 to 20 respirations per minute while at rest. This means that the person will breathe in and out 12 to 20 times during a 60 second period. When counting, make sure to count a breath in and out as one breath to avoid doubling the respiratory number. It is helpful to count a breathing rate when the person is relaxed and is unaware that you are watching her breathing pattern because most people will begin to focus on breathing and disrupt the natural flow if they know that someone is counting the breaths per minute. Normal breathing is typically quiet without wheezes, coughing, bubbling sounds, or other noises. Breath odor is the scent of the air you breathe out of your mouth. Unpleasant, distinctive, or offensive breath odor is commonly called bad breath. Some disorders will produce specific, characteristic odors to the breath. Bad breath related to poor oral hygiene is most common and caused by release of sulphur compounds by bacteria in the mouth.

Conclusion

     Contamination is the presence of a minor and unwanted constituent (contaminant) in material, physical body, natural environment. Poor biological air quality may be connected with some non-biological aspects. As we know, there are many microorganism that are colonized in the free air and also in human body. The exposed of the molten agar to the air and healthy humans cause contamination.

Reference

http://www.biotecharticles.com/Others-Article/Benefits-of-Microorganisms-to-Humans-133.html

http://www.biology.ed.ac.uk/research/groups/jdeacon/microbes/airborne.htm

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

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

 

LAB 4 : ZHAMEIR SHAFIQ BIN MOHD ILIAS 113586

LAB 4 : SOURCES OF CONTAMINATION AND INFECTION

INTRODUCTION

Airbourne microorganisms are usually carried on dust particles or also may be carried by air currents. Awareness about the potential for contamination by airbourne microorganisms is really important and carefully observation is needed in order to reduce the risk of cultures to be contaminate.

The body’s resident microorganism is just that - residents. These species are life-long members of the body's normal microbial community, but are not found everywhere. There are many areas of the human body that remain axenic, and, in the absence of disease, are never colonized by normal flora. Axenic areas include the body cavity, lungs, central nervous system, circulatory system and upper urogenital regions. Resident microorganism is typically colonize the surface of the skin, mucous membranes, digestive tract, upper respiratory system and distal portion of the urogenital system. These microbes have a commensal relationship with their host, meaning that they do not cause harm while they benefit from feeding on the cellular waste and dead cells of the host's body.

Transient microorganisms are picked up from the environment and usually fail to become permanent skin residents. For example, from faecal contact. The most important reasons for failure to gain permanence is that the established residents are better able to compete for the nutrients.

Microorganisms in the upper respiratory tract are either normal residents or transients. As with the skin, the normal microflora largely consists of nonpathogen or opportunistic pathogens. Large numbers of transients enter the upper respiratory tract when we breathe or eat. They may also come from our hands or from improper sanitation during food preparation. 

FIGURE 1

OBJECTIVE

·         To determine the microorganisms in the air and from healthy human

RESULTS

FIGURE 2 : AIR

FIGURE 3 : HAND

FIGURE 4 : NORMAL BREATHING

FIGURE 5 : VIOLENT COUGHING

FIGURE 6 : EAR

DISCUSSION

               Bacteria are one-celled organisms visible only with a microscope. We can find them in the air, on food, plants and animals, in the soil, in the water, and on just about every other surface – including our body. Pathogenic bacteria, the harmful kind, enter the human body from the air, water or food. Once inside, these bacteria attach themselves to or invade specific cells in our respiratory system, digestive tract or any open wound. There they begin to reproduce and spread while using the human body as a source of their own nutrients and energy. 

There are certain amount of bacteria on our hands and usually the bacteria are adapted to living on human skin and are harmless since they help to defend against harmful bacteria. They are millions of bacteria on our hands, also fungi and viruses. Staphylococcus aureus is the most common bacteria found in the nose and on hands. Staphylococcus aureus forms a fairly large yellow colony on rich medium. Staphylococcus aureus can grow at a temperature range of 15˚ to 45˚ degrees. These bacteria  are perfectly spherical cells about 1 micrometer in diameter. Staphylococcus aureus grow in clusters because the cells divide successively in three perpendicular planes with the sister cells remaining attached to one another following each successive division. Since the exact point of attachment of sister cells may not be within the divisional plane and the cells may change position slightly while remaining attached, the result is formation of an irregular cluster of cells.

                The outer ear is home to a varied collection of bacteria, yeasts and molds.The most common bacteria are Staphylococcus epidermis, Turicellaotitidis, Alloiococousotitis, Pseudomonas aeruginosa, Corynebacterium, Staphylococcus aureus, and Streptococcus saprophyticum.  The most common fungal microbe known to reside in the ear is Candida albicans. For the middle ear,microbes that inhibits are Streptococci, Haemophilus pneumoniae, Moraxella catarrhalis, and Mycobacterium and these bacteria are moving to the middle ear through nasophraynx and Eustachian tube.

                For normal breathing, there are many microbes live in the nose and throat but for the lower respiratory structures--the larynx, trachea, bronchi, bronchioles, and alveoli have built-in barriers. The narrowing of the tubes keeps some bugs out, and the numerous waving, hair-like cilia that fringe the cells lining the tract propel bugs up and out.

                The mouth harbors the most bacteria of any body part. Streptococcus mutans, causes dental cavities, but only under certain conditions. Sticky foods, such as candy and raisins, enable the bugs to cling to teeth, where they produce acids that eat away at tooth enamel.

CONCLUSION

                Bacteria are everywhere and can spread from surface to surface, person to person, food to food, and person to food. Harmful bacteria can be controlled by practicing the 4 Cs of food safety. To prevent the spread of harmful bacteria, proper cleaning of both hands and surfaces is especially important.  The good thing is that not all bacteria are harmful; most bacteria are beneficial to us.When designing experiments, you should always use safe techniques when working with bacteria. Also, it's important to have a control plate. In this experiment, you also learned that different strains of bacteria can be identified through colony morphology.

REFERENCE

http://answers.reference.com/wellness/conditions/what_is_contamination

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

http://www.relfe.com/lactobacillus.html

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

LAB 4 MAYA EMIRA BINTI MAD SAAD 111381

 

SOURCES OF CONTAMINATION AND INFECTION

INTRODUCTION

 

There are many kind of microorganism contains in our surroundings.We can classfied all these microorganisms into three type that is resident microorganism,transient microorganism and airborne microorganism.

Airborne microorganisms is microbes that  moved through or by the air. Dust and mist are examples of airborne substances. Airborne bacteria increased with temperature and wind velocity whereas airborne fungi increased with temperature and varied with wind direction in urban and natural areas.

Transient bacteria  is bacteria that it is in the surface of the skin and therefore come and goes as we touch things and as we move around.There are numerous health benefits of transient microorganisms. 

Resident microorganisms are either non-pathogenic or are prevented from infecting the body by an array of mechanical and chemical defenses.Some president microbes are, however, opportunistic pathogens which cause infection if the body defenses are breached.

OBJECTIVE

To determine the microorganisms in the air and from healthy human

RESULT

 

 NORMAL BREATHING

  VIOLENT COUGHING

 HAND

 AIR

  EAR

DISCUSSION

Hand and ear :Resident microorganism live on or within the body in nonsterile areas include the skin,mucous membrane, bowel,rectum and vagina.Inflammatory and immune attacks are generally not waged against this inhabitants as long as the skin and mucusa remain intact.Resident flora compete with diseases-producing microorganisms to protect the body against certain infection snd to provide a type of natural immunity.More than one type of resident flora can be found on superfacial skin tissues or mucuos membrane.A delicate balance of homeostasis is maintained with these residents.Destroying one type of microorganisms can allow overpoliferation of another competing type.

Resident microorganism can be include Staphylococcus species and diptheroids.These microorganism are considered permenant resident of the skin and are not readily removed by mechanical friction.Resident microorganisms in deep layer  may not be removed by hand washing with plain soaps and detergent,but they can usually be killed or inhibited by hygiene products that contain antimicrobial ingredients.Bacillus laterosporus is one of the most enigmatic of the transient friendly microorganisms found in the human gastrointestinal tract. It has been demonstrated to provide phenomenal relief from symptoms of disease and ill health particularly those symptoms associated with suppressed immune system function such as , chronic fatigue syndrome, Candida infections, Epstein-Barr virus, herpes, Crohn’s disease, chlamydia, cytomegalovirus, parasitic infections, and many more. 

Streptococcus thermophilis is a transient microorganism that produces a number of antibiotic like substances as part of its metabolic process. This aids the body in its ongoing fight against disease causing microbes. Perhaps more importantly, S. thermophilis also helps to suppress tumor development and growth in laboratory studies.Moreover, S. thermophilis produces substantial quantities of the enzyme lactose. So it aids in the digestion of milk sugars and may provide an effective remedy against lactose intolerance a condition that afflicts nearly two-thirds of the world’s population. It has also been used in hospitals as an effective remedy for chronic diarrhea in infants.

Transient microorganisms are different from resident microorganisms in that they do not take up permanent residence in the gastrointestinal tract. Instead, they establish small colonies for brief periods of time before dying off or being flushed from the intestinal system via normal digestive processes, or by peristaltic bowel action.However, in taking up temporary residence, they contribute to the overall function and condition of the digestive system. For example, the lives of some of the most important resident micro organisms involved in human digestion and intestinal health depend on by products produced by the visiting transients.Therefore, in many cases, these two very different types of microorganisms nonetheless enjoy a complex symbiotic relationship that may dramatically influence the health and well being of your entire body.

Air,normal breathing and coughing: Airborne bacteria can have important effects on human health as pathogens or triggers of allergenic asthma and seasonal allergies.Infection normally occurs after inhaling an aerosol (fine airborne particles) containing bacteria.Mycobacterium tuberculosis is a bacterium that cause tuberculosis and is spread through indoor aerosol.Tuberculosis is infects a large number of people and is a mojor airborne pathogen.Legionella pneumophila.When inhaled,this bacteria cause a pneumonia-like illness called Legionnaires' diseases and  a similiar,influenza-like disease called Pontiac fever.These bacteria are known to inhinit intracellular structures of higher microorganisms including protozoa,which can provide them with protection from the enviroment and disinfection.Certain fungi such as opportunistic pathogens Aspergillus fumigatus and Pneumocystis carinii can infect the lungs of the immunocompromised,including AIDS patients.Symptoms of infection may include fever,cough,chest pain,and pneumonia.These fungi most commonly originate from soil and enviroment.

 

CONCLUSION

Microorganisms that consist at the surrounding or in our body may have it own benefits to our body or can effects our body to.A lot of diseases come from the infection of bacteria from our surroundings.Thus,we  always need take care of our hygiene so that we not easily infected.  

REFERENCES

http://www.ems.org.eg/esic_home/data/giued_part1/Hand_Hygiene.pdf

http://www.netdoctor.co.uk/health_advice/facts/cough.htm

ORAL microbiology,Richard J. Lamont, Howard F. Jenkinson

http://www.sciencedaily.com/releases/2006/12/061219170636.htm 

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2199786/pdf/jhyg00204-0100.pdf

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

Legal Aspects of Infectious Diseases by Benjamin Tanner

LAB 3 MOHAMMAD SYAFIQ BIN ABDULLAH 113569

INTRODUCTION

Culture media are available commercially as powders; they require only the addition of water. Nutrient medium is a general purpose preparation for  culturing microorganisms which are not nutritionally fastidious. The broth contains:

3.0 g/L “Lab-lemco” powder (beef extract)

2.0 g/L yeast extract

5.0 g/L peptone (nitrogen source)

5.0 g/L sodium chloride

2.0 g/L agar powder

The agar has the same composition, except that contains 15 g/L agar. The final pH of both media is 7.4

Autoclaves are widely used in microbiology, medicine, tattooing, body piercing, veterinary science, mycology, dentistry, chiropody and prosthetics fabrication. They vary in size and function depending on the media to be sterilized.

Typical loads include laboratory glassware, surgical instruments, medical waste, patient pair utensils, animal cage bedding, and lysogeny broth.

A notable growing application of autoclaves is the pre-disposal treatment and sterilization of waste material, such as pathogenic hospital waste. Machines in this category largely operate under the same principles as conventional autoclaves in that they are able to neutralize potentially infectious agents by utilizing pressurized steam and superheated water. A new generation of waste converters is capable of achieving the same effect without a pressure vessel to sterilize culture media, rubber material, gowns, dressing, gloves, etc. It is particularly useful for materials which cannot withstand the higher temperature of a hot air oven. For all-glass syringes, sterilizing in a hot air oven is a better method.

OBJECTIVE

To prepare sterile nutrient agar for culturing microorganisms.

DISCUSSION

a source of amino acids and nitrogen (e.g., beef, yeast extract).  This is an undefined medium because the amino acid source contains a variety of compounds with the exact composition being unknown. Nutrient media contain all the elements that most bacteria need for growth and are non-selective, so they are used for the general cultivation and maintenance of bacteria kept in laboratory culture collections.

Physcomitrella patens plants growing axenically on agar plates. An undefined medium (also known as a basal or complex medium) is a medium that contains a carbon source such as glucose for bacterial growth, water and various salts needed for bacterial growth. A defined medium (also known as chemically defined medium or synthetic medium) is a medium in which all the chemicals used are known no yeast, animal or plant tissue is present. A differential medium is a medium that includes some sort of added indicator that allows for the differentiation of particular chemical reactions occurring during growth.

They are different sterilization methods for medical instruments, consumables, devices and Implantable devices. Depending on the nature of the product to sterilize is the method used.
Sterilization can be achieved through application of heat, chemicals, irradiation, high Pressure or filtration.
Heat Sterilization is divided in two categories: 

·         Dry Heat Sterilization

·         Moist Heat sterilization

Dry heat sterilization of an article is one of the earliest forms of sterilization practiced. Dry heat, as the name indicates, utilizes hot air that is either free from water vapour, or has very little of it, and where this moisture plays a minimal or no role in the process of sterilization.
Methods Used: 

·         Hot air oven

·         Incineration or Burning 

·         Flamming 

·         Radiation

·         Microwave

The most used in the medical field is "Hot air Oven"
Moist Heat Sterilization as the name indicates, utilizes hot air that is heavily laden with water vapour and where this moisture plays the most important role in the process of sterilization.
Methods Used: 

·         Water bath

·         Pasteurization (milk)

·         Boilling

·         Steam Sterilizer

·         Autoclave

The most used in Medical Field is "Autoclave" 

CONCLUSION

All living organisms require energy. They can get their energy from multiple sources: organic chemicals(carbon containing compounds), inorganic chemicals and light. Bacteria use organic chemicals, such as, sugars, starch, protiens and fats to grow. Bacteria are called heterotrophs.

Most bacteria grow best at normal, human body temperature (98-99 degrees F). When growing the bacteria, incubate at a temperature as close to this as possible. The bacteria will grow slower at lower temperatures.

Aseptic technique is the process of growing and transferring bacteria without contaminating the culture by touching or breathing on the sample.

Nutrient agar is a general purpose prepared media and grows many types of bacteria and fungi. If you have a specific bacteria culture, you can spread the bacteria on the plate using a sterile swab or innoculating loop. The bacteria will grow and become visible in 24-48 hrs. If you would like to determine the types of bacteria growing on a sink, chair, table or other areas, a sterile swab can be used to rub across the area you would like to test. After the sample is taken, you can transfer the bacteria to the nutrient agar plate by swiping the swab across the surface of the agar plate. After 24-48 hrs, you may find many, different looking colonies growing on the nutrient agar plate. Each type of bacteria look a little different (color, shape, size) when they grow.

REFERENCE

http://www.gadgetscience.com/growing-bacteria-on-nutrient-agar-plates/

http://wiki.answers.com/Q/What_are_the_Advantages_and_disadvantages_of_heat_sterilization_on_medical_equipment

LAB 3 : SHAHRUL EZZATI BT SHAHRUL AMIR -111416-

PREPARATION AND STERILIZATION OF CULTURE MEDIA

Introduction

Microorganisms need nutrients, a source of energy and certain environmental conditions in order to grow and reproduce. In the environment, microbes have adapted to the habitats most suitable for their needs, in the laboratory, however, these requirements must be met by a culture medium. This is basically an aqueous solution to which all the necessary nutrients have been added. Depending on the type and combination of nutrients, different categories of media can be made.

Complex media are rich in nutrients, they contain water soluble extracts of plant or animal tissue (e.g., enzymatically digested animal proteins such as peptone and tryptone). Usually a sugar, often glucose is added to serve as the main carbon and energy source. The combination of extracts and sugar creates a medium which is rich in minerals and organic nutrients, but since the exact composition is unknown, the medium is called complex.

Defined media are media composed of pure ingredients in carefully measured concentrations dissolved in double distilled water i.e., the exact chemical composition of the medium is known. Typically, they contain a simple sugar as the carbon and energy source, an inorganic nitrogen source, various mineral salts and if necessary growth factors (purified amino acids, vitamins, purines and pyrimidines).

Selective/differential media are media based on either of the two categories above supplemented with growth-promoting or growth-inhibiting additives. The additives may be species- or organism-selective (e.g., a specific substrate, or an inhibitor such as cyclohexamide (artidione) which inhibits all eucaryotic growth and is typically used to prevent fungal growth in mixed cultures).

The mixture of necessary nutrients can be used as a liquid medium, or a solidifying agent can be added. "Agar agar" is a natural polysaccharide produced by marine algae and is the most commonly used solidifying agent added to media (end concentration usually 1.5 % w/v). If hydrolysis of the agar is suspected, a silica gel is used as a replacement solidifying agent. The broth contains:

0.6 g/L "Lab-lemco" powder (a beef extract)

0.4 g/L yeast extract

1.0 g/L peptone (a nitrogen source)

1.0 g/L sodium chloride

3.0 g/L agar powder

An autoclave is an instrument used to sterilize equipment and supplies by subjecting them to high pressure saturated steam at 121 °C for around 15–20 minutes depending on the size of the load and the contents. It was invented by Charles Chamberland in 1879, although a precursor known as the steam digester was created by Denis Papin in 1679. The name comes from Greek auto-, ultimately meaning self, and Latin clavis meaning key — a self-locking device.

A autoclave is a device that uses steam to sterilize equipment and other objects. This means that all bacteria, viruses, fungi, and spores are inactivated. However, prions, like those associated with Creutzfeldt-Jakob disease, may not be destroyed by autoclaving at the typical 134 °C for three minutes or 121 °C for 15 minutes. Also, some recently-discovered organisms, such as Strain 121 microbes, can survive at temperatures above 121 °C.

Objective

To prepare sterile nutrient agar for culturing microorganisms

Discussion

Yeasts are chemoorganotrophs, as they use organic compounds as a source of energy and do not require sunlight to grow. Carbon is obtained mostly from hexose sugars, such as glucose and fructose, or disaccharides such as sucrose and maltose. Some species can metabolize pentose sugars like ribose, alcohols, and organic acids. Yeast species either require oxygen for aerobic cellular respiration (obligate aerobes) or are anaerobic, but also have aerobic methods of energy production (facultative anaerobes). Unlike bacteria, there are no known yeast species that grow only anaerobically (obligate anaerobes). Yeasts grow best in a neutral or slightly acidic pH environment.

Yeasts vary in what temperature range they grow best. The cells can survive freezing under certain conditions, with viability decreasing over time. In general, yeasts are grown in the laboratory on solid growth media or in liquid broths. Common media used for the cultivation of yeasts include potato dextrose agar (PDA) or potato dextrose broth, Wallerstein Laboratories nutrient (WLN) agar, yeast peptone dextrose agar (YPD), and yeast mould agar or broth (YM). Home brewers who cultivate yeast frequently use dried malt extract (DME) and agar as a solid growth medium. The antibiotic cycloheximide is sometimes added to yeast growth media to inhibit the growth of Saccharomyces yeasts and select for wild/indigenous yeast species. This will change the yeast process.

Agar (aka agar-agar from red seaweed) is a polysaccharide polymer and provides the support structure in the bacteriological medium. Agar gives a solid support so that bacterial colonies can form on the surface of the agar medium while allowing the diffusion of nutrients and water. The structural function of agar in bacteriological media is similar to the function that gelatin has in Jell-O. In bacteriological media, agar and nutrients are added together and the specific nutrients are chosen for the particular type of bacteria you want to grow and for the conditions under which you want the bacteria to grow. Agar is used rather than gelatin because agar isn't broken down by most bacteria.

Conclusion

This report has identified on how to prepare the culture media in the laboratory. It is also identified on what it the purpose of agar in culture media and what is the yeast need for growth. Other than that, the uses of autoclave for sterilization is identify. It is use to avoid contamination and it is works under high steam pressure and temperature. 

References

1) http://en.wikipedia.org/wiki/Autoclave

2) http://www.sigmaaldrich.com/analytical-chromatography/microbiology/learning-center/theory/media-preparation.html

3) http://en.wikipedia.org/wiki/Yeast

4) http://answers.yahoo.com/question/index?qid=20080818042920AAUAALS

LAB 3 : ZHAMEIR SHAFIQ BIN MOHD ILIAS 113586

PREPARATION AND STERILIZATION OF CULTURE MEDIA

INTRODUCTION

Microorganisms are available in all places and surrounding environment and it is difficult to us to find their original habitat. So, in order to cultivate the microorganisms, the factitious condition in laboratory is created. A culture medium is a liquid or gel that designed to support the growth of microorganisms or cells. In the other hand, culture media are available commercially as powders which they are only required the addition of water. There are many different types of media and the most common culture media for microorganisms are broth and agar. The contains for broth are :

·         3.0 g/L “Lab-lemco” powder (a beef extract)

·         2.0 g/L yeast extract

·         5.0 g/L peptone ( a nitrogen source)

·         5.0 g/L sodium chloride

·         2.0 g/L agar powder

For agar, it also has the same composition as broth except that it contains 15 g/L agar. Final pH for the both media is 7.4.

 To sterilize all parts of the material, autoclave process is needed. Autoclave process used moist heat and pressure to sterilize the materials at 121  ͦC for 15 minutes.  But, it is depending on the size of the load and the contents. An autoclave is like a large pressure cooker  which have a chamber and the chamber have to be sealed off against surrounding air. Materials that have to be sterilize must be placed in the chamber, sealed the door and pressurized steam is forced into the chamber. The steam will displaces cooler air through an exhaust valve. Steam will continually forced to the chamber until it reaches the pressure 103 kPaabove the atmospheric pressure and this will increase the temperature to 121˚C. The high pressure will prevents the solutions from boiling over at this temperature. Longer than 15 minutes is required when the volume is larger to heat up to 121˚C. The steam pressure can be decreased slowly to atmospheric pressure when the sterilization process finished and then the sterilized objects can be removed.

Figure 1 : autoclave machine

OBJECTIVE

·         To prepare sterile nutrient agar for culturing microorganisms.

DISCUSSION

There are several steps in preparing the culture medium. Firstly, cleaned the pan and inside of the balance with brush. This step must be done before weighing the culture medium powder because to avoid the error during reading the weigh. Then, put the container onto the balance and press “tare” button to get the accurate reading. In the other hand, distilled water is measured by measuring cylinder. Make sure that do not pour all the water into the beaker because it should be some distilled water have to be reserved to washing the leftover powder from the weighing container to the beaker. After that, to make sure the correct composition of culture media is produced, the correct amount of water is added. Then, stirred the media by using rod to ensure that the media dissolved fully in water. Next step is put the entire medium into the Scott bottles. Labelled the bottles and loosen the cap of the bottles before put it into the autoclave machine. This is because autoclave works under the high steam pressure and loosen the cap will allow the expansion of the bottles and the bottles will not break. After autoclave, Scott bottles is removed and the cap is tightened. The bottles should be turned overagain for a few times so that no agar will solidifyat the bottom of the bottles. This is to make sure that the culture agar can be used for the pour-plate in the next laboratory.

CONCLUSION

This report has identifed on how to prepare the culture media in the laboratory. Commercial nutrient agar is used because it prepare suitable medium for microorganisms growth. Then, sterilization process is required to culture the microorganisms in the nutrient agar in order to avoid the contamination. Autoclave process also used in this preparation for sterilize the nutrient agar and it is works under the high steam pressure and temperature.

REFERENCES

 http://www.sigmaaldrich.com/life-science/molecular-biology/plant-biotechnology/tissue-culture-protocols/media-preparation.html

http://www.sigmaaldrich.com/life-science/molecular-biology/plant-biotechnology/tissue-culture-protocols/media-sterilization.html

http://www.cabri.org/guidelines/micro-organisms/M203Ap1.html

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

LAB 3 MAYA EMIRA BT MAD SAAD 111381

PREPARATION AND STERILIZATION OF CULTURE MEDIA

INTRODUCTION

Bacteria grown in a laboratory environment, like captive animals in a zoo, need to have everything provided for them such as food, water, a suitable environment,in order to survive and thrive. Some microbes are not especially choosy in their requirements for growth, while others, such as Treponema pallidum, the causative agent of syphilis, has never been successfully grown in culture, although scientists have been trying to do so for more than 100 years.

Several basic types of media are discussed below. Although their differences are featured, there are several characteristics that all culture media have in common. Media must be prepared in such a way that it is sterile prior to being inoculated with a bacterial sample, so that when a particular type of bacteria is cultured (cultivated) on that medium, it is the only type of bacteria present. Growth media must also provide everything the bacterial culture needs to live and grow, including water, nutrients, and the proper pH. Media can be eitherliquid (nutrient broth) or solid (agar).

Most clinical cultures do not have such exacting requirements, and can be grown in what is referred to as “complex media”. Complex media are composed of partially digested yeast, beef, soy and additional proteins, in which the exact concentration and composition is unknown. In comparison with defined media, which are good for growing bacteria with very particular needs, complex media can be thought of as a crowd-pleaser, suitable for growing many different types of less fastidious microbes.

In addition to growth media formulations being classified as either defined or complex, there are also media that are designed to do more than just grow bacteria, selective and differential media provide information about the bacteria growing.

Selective media contain ingredients that inhibit the growth of certain types of bacteria and encourage the growth of others. This type of media is useful in helping to identify unknown bacteria and in encouraging the growth of only the types of bacteria that the microbiologist is interested in cultivating.

For example MacConkey’s Agar (MAC) is used to cultivate Gram-negative bacteria, by discouraging the growth of Gram positive bacteria through the use of crystal violet dyes and bile salts. Mannitol Salt Agar (MSA) has a high concentration of sodium chloride, which selects for halophiles (salt-loving bacteria) such as members of the genus Staphylococcus.

Differential culture media are formulated to display a color change when the bacteria growing utilize a certain ingredient. For example MacConkey's Agar, in addition to being selective, contains the sugar lactose and a pH sensitive dye. When bacteria growing on MAC ferment lactose (metabolize it for food), they generate waste products that trigger the pH sensitive dye to turn the bacteria pink.
Mannitol Salt Agar also contain food (mannitol, a sugar alcohol) and a pH sensitive dye. When the bacteria growing on MSA ferment mannitol, the medium changes from its original pink color to a bright yellow. Another specialized medium, Blood Agar (BAP) contains sheep’s blood, if bacteria growing on the medium produce exotoxins that hemolyze (cut up blood cells), the medium changes color.

Culture media must be stored at the specified temperature, under specified conditions and not longer than the shelf-life periods appropriate to each product. The storage conditions and expiry date of each product are shown on the labels or product inserts but the following general rules will help to ensure that they are kept in an optimum environment. When storing products note the shelf life expiry dates on the labels and use the products in order of their lot/batch numbers.

Light

All prepared culture media and their components should be stored away from light and exposure to direct sunlight should be avoided at all times.

Humidity

Sealed glass and plastic containers are unaffected by normal laboratory humidity. Opened containers of dehydrated powders will be affected by high humidity. Hot, steamy media preparation rooms are not suitable environments to store containers of culture media; particularly containers which are frequently opened and closed. An adjacent cold room or an adequate storage cupboard are preferable storage areas.

Temperature and time

Culture Media:  Sealed, unopened containers should be stored at room temperature 15-20°C. Opened containers should have the cap or lid carefully and securely replaced. It is important that opened containers are stored in a dry atmosphere at room temperature. Shelf life 1 to 5 years..

 

OBJECTIVES

To prepare sterile nutrient agar for culturing microorganism

DISCUSSION

An autoclave is an instrument used to sterilize equipment and supplies by subjecting them to high pressure saturated steam at 121 °C for around 15–20 minutes depending on the size of the load and the contents.

Autoclaves are widely used in microbiology,medicine,mycology,dentistry,chiropody and prosthetics fabrication. They vary in size and function depending on the media to be sterilized.
Typical loads include laboratory glassware, surgical instruments, medical waste, patient pair utensils, animal cage bedding, and lysogeny broth.


A notable growing application of autoclaves is the pre-disposal treatment and sterilization of waste material, such as pathogenic hospital waste. Machines in this category largely operate under the same principles as conventional autoclaves in that they are able to neutralize potentially infectious agents by utilizing pressurized steam and superheated water. A new generation of waste converters is capable of achieving the same effect without a pressure vessel to sterilize culture media, rubber material, gowns, dressing, gloves, etc. It is particularly useful for materials which cannot withstand the higher temperature of a hot air oven. For all-glass syringes, sterilizing in a hot air oven is a better method.


Autoclaves are also widely used to cure composites and in the vulcanization of rubber. The high heat and pressure that autoclaves allow help to ensure that the best possible physical properties are repeatably attainable.
It is very important to ensure that all of the trapped air is removed from the autoclave before activation, as hot air is a very poor medium for achieving sterility. Steam at 134 °C can achieve in three minutes the same sterility that hot air at 160 °C takes two hours to achieve. Methods of achieving air removal include:

 Downward displacement (or gravity-type) - As steam enters the chamber, it fills the upper areas first as it is less dense than air. This compresses the air to the bottom, forcing it out through a drain which often contains a temperature-sensing device. Only when air evacuation is complete does the discharge stop. Flow is usually controlled by a steam trap or a solenoid valve, but bleed holes are sometimes used, often in conjunction with a solenoid valve. As the steam and air mix it is also possible to force out the mixture from locations in the chamber other than the bottom.

Steam pulsing - air dilution by using a series of steam pulses, in which the chamber is alternately pressurized and then depressurized to near atmospheric pressure.

Vacuum pumps - a vacuum pump sucks air or air/steam mixtures from the chamber.

Superatmospheric cycles - achieved with a vacuum pump. It starts with a vacuum followed by a steam pulse followed by a vacuum followed by a steam pulse. The number of pulses depends on the particular autoclave and cycle chosen.

Subatmospheric cycles - similar to the superatmospheric cycles, but chamber pressure never exceeds atmospheric pressure until they pressurize up to the sterilizing temperature.

 

REFERENCES

Bauman, R. (2007). Microbiology with Diseases by Taxonomy. Pearson Benjamin Cummings.

Perry, J. and Stanley, J. (1997) Microbiology Dynamics & Diversity. Saunders College Publishing.

http://www.protocol-online.org/biology-forums-2/posts/18634.html

http://www.cabri.org