The term microorganisms also called microbes make reference to small tiny solo celled organisms not often visible to the naked attention. Microorganisms require magnification for proper visualization and quality of their structure. These involve use of microscopes or magnifying lens with appropriate level of magnification (Tortora, Funke and Case 1995). Microorganisms are found in every living things all over the world i. e. plant life and animals. They exist in a number of habitats. They are able to reside in air, on land or in water both fresh and salty. The three main classes of microorganisms are bacterias, fungi and viruses. Different microorganisms have different results. Some are damaging while others are beneficial. Pathogenic and spoilage microbes cause diseases and food spoilage respectively thus referred to as hazardous microorganisms. We also have others that are needed by living things to survive and they're referred to as beneficial microbes (Tortora, Funke and Case 1995).
Microbes are labeled either by inserting them in prokaryote or eukaryote group or by classifying them according to the temperature in their adjoining environment where they may be grouped as thermophilic microbes (thermophiles), mesophilic microbes (mesophiles) or psychrophilic microbes (psychrophiles). Thermophilic microbes are those microbes that grow well in high temperature above the body temperatures. Mesophilic microbes are those that increase well in conditions equal to that of human body while psychrophililic microbes are those that expand well in low temperature ranges below that of body (Jaggi 1985).
Like some other living organism, microbes reproduce for advancement of their types. They reproduce through either erotic or asexual duplication. Sexual duplication occurs by mating of an male and a lady while asexual duplication is by cell division either by mitosis, meiosis or binary fission.
Micro-organisms can be counted. They need to be discovered first before being counted. There are many techniques involved when keeping track of microbes. A number of of the following techniques may be used when counting microbes. Direct keeping track of techniques can be utilized. The oldest of these is microscopy which involves magnification of individual cells to be obvious to the naked eyes. Direct counting techniques do not count on cell society growth. A more recent of the direct counting techniques consists of use of immunofluorescence and epifluorescence adaptations of cell labeling found in conjunction with cytometry. In both systems, the lead to for a count comes from single skin cells (Diaper et al. 1992).
We likewise have culture techniques that rely on growth of microbes to a level where these are visible. That is done under specific conditions of temps, oxygen, time and nutrition among others.
The last technique used is that of reporter assays which asses the populace of microbes through their metabolic activities. The populace does not actually need to be growing. Examples of such techniques include conductance, colorimetry, adenosine triphosphate (ATP) and turbidometry (Bowden 1977).
Counting of microorganisms can be carried out by different methods. Generally the test to be counted is first diluted to avoid overwhelming the whole counting procedure. Yet, in some cases, the sample may be too dilute to provide the required minimum amount count to be able to calculate the microbial inhabitants of that sample. In such instances, awareness of the sample is completed.
Counting can be carried out by use of your slip and a cover slide. A drop of the diluted test is placed on the glide with a suitable agent for proper visualization of the test. It is then covered wit a cover slip and put under a microscope and detected at the right magnification. The centre area can be dimensioned with etched grids. The number of microbes in the grids is multiplied by the dilution factor to get the number in the initial sample (Dark 1996).
The Petri dish matter is where in fact the sample is diluted to a point where the colonies will be statistically significant to be counted but not so many to overgrow each other. This method does take time for the individual cells to grow into colonies. The colonies counted are multiplied by the dilution factor to get the quantity in the original sample. The results here are expressed in colony building units per milliliter i. e. CFU/ML. Enough time taken for the skin cells to grow into specific colonies is named the incubation period. Counting of microbes is important as it permits us estimate the microbial people in a variety of products (Breeuwer et al. 1994).
Total matter is also referred to as standard plate count number or colony count up. It gives the total number of microbes both practical and non-viable. All cells are counted. Included in these are bacteria, yeasts and moulds. It is usually done by pour dish method. Total count number generally requires occupation of an microscope.
For occasion, when identifying total microbial count in normal water by pour dish, a known volume of water is blended with molten yeast-malt remove agar and given time to solidify. This is done on several plates. One group of plates are incubated at 37C for about 24 hours and the other group of plates are incubated at 20-22C for 3 days. You will find that most bacteria capable of expansion in water do so well at 22C than at higher temperatures. While the microbes that grow well at 37C will not grow very well in water. This means that the two types of microorganisms need to be counted differently since they change in their progress pattern. In this case, carrying out of total depend on water is beneficial in a number of ways (Paulse, Jackson and Khan 2007). It helps to evaluate the efficiency of certain water treatment processes like coagulation, flocculation and disinfection. In addition, it gives an indication of the amount of cleanliness of the circulation system. It can be used it determine the suitability of drinking water supply to organizations where food and beverages are prepared on large size.
Total count is achieved either by use of direct or indirect matters. One method of direct count is the utilization of an haemocytometer. A haemocytometer is a specific microscope slide important in cell keeping track of. The central part of this glide has etched grids with accurately spaced lines make it possible for accurate counting. To be able to get a precise count in this method, the cell number should range between 40 to 70 skin cells in a one mm square. If this requirement is not fulfilled, necessary alterations by either dilution or attentiveness are done as necessary (Rapposch, Zangerl and Ginzinger 2000).
In indirect counts, one technique is by use of any colorimeter. As the microorganisms increase as time passes, they make the agar increasingly more turbid. This turbidity can be measured by use of the colorimeter where optical thickness is measured. The higher the optical denseness the greater the number of microbes (Breeuwer et al. 1995).
There is also a way of measuring dry weight. This technique involves centrifugation accompanied by weighing to get the dried weight. The limitation of this method is that skin cells are destroyed
The other indirect matter method involves the use of the coulter counter. A coulter counter is a probe which steps deviation in conductivity of a solution as a bacterias passes via a narrow difference (Daley 1979).
The advantage of immediate and indirect counts is that the procedure can be computerized but the downside is that they can not differentiate dead cells from living ones.
Viable cont will involve keeping track of of colonies made by only viable cells under favorable progress conditions. This can be accomplished by techniques like pour plating, spread plating & most probable quantity with an assumption that each and every viable cell offers go up to a pure colony.
In put plating, the liquid media and the diluted test are poured jointly in Petri meals while still in liquid form and left to solidify. After solidifying, the Petri food are incubated at appropriate heat range for the mandatory period of time where the progress is understood. The plates are then removed and unique colonies counted and portrayed in colony developing items per ml.
In get spread around plating, the media is prepared individually and poured in Petri dishes while still in liquid form. It really is then still left to solidify. After solidifying, a little known volume from the diluted test is put to each Petri dish and with the help of a sterilized spreading rod, the sample is evenly multiply over the press. The plates are then incubated at an appropriate temperature for confirmed period during which growth is became aware. The plates are then considered for keeping track of of colonies using magnifying zoom lens (Dark colored 1996).
Colonies produced in Petri food by various methods excluding streaking method enable you to estimate the count up of practical microbes since plate counts assume that every colony is founded by an individual cell and that the cell will need to have been alive to increase and form that colony.
Problems with plate matters are several. They require quite a while of incubation to be able to imagine the colonies. Clumping of cells can result in undercounting of practical cells. Cases of too many or too few colonies on the plate to effectively estimate viable matter are common. Serial dilution is often necessary to prevent instances of overcrowding of cells. Too few skin cells require focus by either centrifugation or purification. In a circumstance where too little colonies are present then the original culture must be focused before identifying the plate matter. Filtration is a method used to focus microorganisms by sieving microbes from the medium. Centrifugation is also a parting method predicated on the density. This can help separate the microbes from the medium since both have different densities (Pettipher, Mansell, McKinnon and Cousins 1980).
. In serial dilution, increments are made in 1000, 100, or 10. The amount of dilutions to be achieved will depend on the concentration of the initial solution and the mandatory concentration. The volume of the perfect solution is needed is also vital. If small levels of alternatives are needed then higher numbers of dilutions are necessary. Serial dilution allows small aliquots to be diluted instead of unnecessary big amounts of materials. When carrying out serial dilution, a small amount of original test is removed to another container and its volume fine-tuned to original size using a appropriate buffer or distilled water e. g. if 1ml of the initial solution is considered and 10L removed and put in 990L of media or drinking water then we will have made a 1:100 dilution. If the initial solution contained 5 x 106 cells/mL then we've a awareness of 5 x 104cells/mL because we've divided the attention by 100 (Pettipher, Mansell, McKinnon and Cousins 1980).
Another approach to determining approximate viable matter is by use of all probable number. This method requires diluting the expansion civilizations and then growing the dilution cultures in broth tubes. This method pays to where it is beneficial to make use of broth other than solid media especially for highly motile microorganisms that happen to be poor in building colonies.
The most probable number method is mainly used when the organism in question is not able to grow on stable agar or in situations where the microorganisms are too few to give reliable measure of society size by the standard plate count number method (Dark 1996).
The good thing about viable count is the fact the method can be produced very hypersensitive and that one can have the ability to depend subsets of inhabitants. However the disadvantage is that sometimes the colony creating devices may underestimate the number of cells because of clumping or chains of cells. It is also time consuming as the counts require at least few time or in a single day for incubation (Bowden 1977).
Viable matter of microbes is mainly suitable in food handling industries mainly dairy and meats processing plants where microbiology is most applicable. It can help in estimation of shelf life of refined foods as well as analysis of sanitary conditions under which the products were built. The efficiency of certain treatment processes like pasteurization, sterilization and cool storage done during creation is also examined by viable microbial matter.
Total and feasible counts of microorganisms are important tactics in microbiology appropriate in fields of drugs, food among others. The primary difference between the two is the fact total count decides the count of all cells both useless and alive while feasible count estimate the amount of practical or live skin cells only capable of growing into particular colonies.