Bacterial Growth, Measure and Control


  1. Discuss the four phases of the bacterial growth curve.

When inoculated in a growth media under optimal conditions, bacteria grow in a distinct pattern of four phases. The growth of the microbes is quantified in numbers and not the size. The phases are lag, log or exponential, stationary and death phases, which are characteristic of bacteria growth in a batch or closed system such as a flask or test tube.

Don't use plagiarized sources. Get Your Custom Essay on
Bacterial Growth, Measure and Control
Just from $9/Page
Order Essay

The lag phase is the initial stage of growth after cells are inoculated in fresh medium, but there is no cell division in this phase. However, the microbes may grow in mass or volume, are metabolically active synthesizing DNA, RNA, proteins and enzymes in readiness for the next phase. The period of the log phase is dependent on various factors such as inoculum size, length of time for the synthesis of new metabolic enzymes and essential coenzymes, and recovery time from physical shock during transfer.

The exponential phase is quite rapid with intense replication of bacteria by binary fission. The number of bacterial colonies increases significantly during this phase with a uniform pattern of division, and the growth rate is by geometric progression. However, the constant growth rate is dependent on the constituents of the culture medium and inoculation conditions. The cells are also susceptible to adverse environmental conditions such as antibiotics and radiation, but positive growth is recorded when the number of generated cells exceeds that of the dead cells (Rosenberger, 2008).

During the stationary phase, the growth rate begins to stabilize with little metabolic activity. There is no increase in population size, and the rate of cell division is slow. Bacteria growth in this phase is limited by various intrinsic factors such as exploitation of resources, waste accumulation, insufficient oxygen, acidic pH medium, and limited space. However, this phase is favorable to bacteria producing secondary metabolites such as antibiotics because it is the peak of production.

In the decline or death phase, the population size reduces, and the cells cannot divide anymore due to harsh inoculation conditions. The rate of cell decrease is geometric at a logarithmic rate and the number of dead cells exceeds that of cells generated. There is no more growth beyond this phase and the cells cycle back to the lag phase and the growth pattern continues (Rosenberger, 2008).

  1. Explain two methods used to measure microbial growth.

Viable microbial cells can be quantified through various methods such as direct and indirect microscopic count and electronic counting chamber. The indirect cell count, otherwise known as plate counts, involves spreading culture sample on nutrient agar and diluting with water before plating. Viable cells grow on the medium and form a colony referred to as colony forming unit (cfu), and each cfu represents the viable number of bacteria cells in culture. The direct microscopic method is executed using counting chambers, which are special slides. The method distinguishes dead cells from the live ones, and only dense cell suspensions of more than 107 cells per ml are quantified. The sensitivity of the cells can be enhanced by increasing the sample suspension through centrifugation. Electronic counting chambers mainly quantify the number and size of the cells such as eukaryotic cells (Kumar, 2012).

  1. Discuss two methods used to control microbial growth.

Control of microbial growth involves inhibition or prevention of microbes by use of chemical and physical methods. The physical methods include radiation, heat, filtration, high pressure, and desiccation while the chemical methods include disinfection and antisepsis. Complete destruction of microbes is called sterilization, which is achieved through various means. Heat is an effective sterilization method, and both dry and moist heat is used (Todar, 2009).

Dry heating methods include incineration, which is a method used to destroy microorganisms by burning them in an incinerator at high temperatures. Used needles, syringes, glassware, and inoculating loops are sterilized using incineration. Moist heating methods include autoclaving and boiling at high temperatures for about 15-30 minutes. Autoclaving is the preferred method of sterilization in hospitals and laboratories. Pasteurization uses mild heat to reduce microbial load in foods and food products such as milk. The use of low heat through refrigeration and deep freezing is also an effective sterilization method. Desiccation methods include osmotic pressure and lyophilization, which are mainly used for food and drug preservation.

Sterilization using irradiation aims at killing the nucleic acid of microorganisms, completing destroying them. Ultraviolet light is the most common irradiation method used, but others such as x-rays and gamma rays are used to disinfect surfaces. Filtration method is used to sterilize heat-sensitive gases and liquids such as vitamins, injectable medicine, antibiotics, and amino acids. The solutions are filtered by use of filters with ultramicroscopic pores to remove the smallest microbial cells (Todar, 2009).

Chemical agents such as alcohol, phenols, iodine, chlorine, aldehydes, quaternary ammonium compounds, and heavy metals such as mercury and silver are examples of disinfectants used to kill microbes on inanimate objects. Antiseptics such as iodine, detergents, hydrogen peroxide and dilute alcohol are mild agents used on living tissues. Cidal agents totally kill microbes on surfaces while those that inhibit their growth are static agents. For example, bactericides kill bacteria while bacteriostatic agents inhibit the growth of bacteria (Todar, 2009).



Kumar, S. (2012). What are the methods of measuring microbial growth? Preserve Articles. Retrieved on 18 March 2014 from com/2012042631158/what-are-the-methods-of-measuring-microbial-growth.html”>

Rosenberger, E. (2008). What are the four phases of bacterial growth. Sciences 360. Retrieved on 18 March 2014 from

Todar, K. (2009). The control of microbial growth. The Microbial World. Retrieved on 18 March 2014 from


Get Professional Assignment Help Cheaply

Buy Custom Essay

Are you busy and do not have time to handle your assignment? Are you scared that your paper will not make the grade? Do you have responsibilities that may hinder you from turning in your assignment on time? Are you tired and can barely handle your assignment? Are your grades inconsistent?

Whichever your reason is, it is valid! You can get professional academic help from our service at affordable rates. We have a team of professional academic writers who can handle all your assignments.

Why Choose Our Academic Writing Service?

  • Plagiarism free papers
  • Timely delivery
  • Any deadline
  • Skilled, Experienced Native English Writers
  • Subject-relevant academic writer
  • Adherence to paper instructions
  • Ability to tackle bulk assignments
  • Reasonable prices
  • 24/7 Customer Support
  • Get superb grades consistently

Online Academic Help With Different Subjects


Students barely have time to read. We got you! Have your literature essay or book review written without having the hassle of reading the book. You can get your literature paper custom-written for you by our literature specialists.


Do you struggle with finance? No need to torture yourself if finance is not your cup of tea. You can order your finance paper from our academic writing service and get 100% original work from competent finance experts.

Computer science

Computer science is a tough subject. Fortunately, our computer science experts are up to the match. No need to stress and have sleepless nights. Our academic writers will tackle all your computer science assignments and deliver them on time. Let us handle all your python, java, ruby, JavaScript, php , C+ assignments!


While psychology may be an interesting subject, you may lack sufficient time to handle your assignments. Don’t despair; by using our academic writing service, you can be assured of perfect grades. Moreover, your grades will be consistent.


Engineering is quite a demanding subject. Students face a lot of pressure and barely have enough time to do what they love to do. Our academic writing service got you covered! Our engineering specialists follow the paper instructions and ensure timely delivery of the paper.


In the nursing course, you may have difficulties with literature reviews, annotated bibliographies, critical essays, and other assignments. Our nursing assignment writers will offer you professional nursing paper help at low prices.


Truth be told, sociology papers can be quite exhausting. Our academic writing service relieves you of fatigue, pressure, and stress. You can relax and have peace of mind as our academic writers handle your sociology assignment.


We take pride in having some of the best business writers in the industry. Our business writers have a lot of experience in the field. They are reliable, and you can be assured of a high-grade paper. They are able to handle business papers of any subject, length, deadline, and difficulty!


We boast of having some of the most experienced statistics experts in the industry. Our statistics experts have diverse skills, expertise, and knowledge to handle any kind of assignment. They have access to all kinds of software to get your assignment done.


Writing a law essay may prove to be an insurmountable obstacle, especially when you need to know the peculiarities of the legislative framework. Take advantage of our top-notch law specialists and get superb grades and 100% satisfaction.

What discipline/subjects do you deal in?

We have highlighted some of the most popular subjects we handle above. Those are just a tip of the iceberg. We deal in all academic disciplines since our writers are as diverse. They have been drawn from across all disciplines, and orders are assigned to those writers believed to be the best in the field. In a nutshell, there is no task we cannot handle; all you need to do is place your order with us. As long as your instructions are clear, just trust we shall deliver irrespective of the discipline.

Are your writers competent enough to handle my paper?

Our essay writers are graduates with bachelor's, masters, Ph.D., and doctorate degrees in various subjects. The minimum requirement to be an essay writer with our essay writing service is to have a college degree. All our academic writers have a minimum of two years of academic writing. We have a stringent recruitment process to ensure that we get only the most competent essay writers in the industry. We also ensure that the writers are handsomely compensated for their value. The majority of our writers are native English speakers. As such, the fluency of language and grammar is impeccable.

What if I don’t like the paper?

There is a very low likelihood that you won’t like the paper.

Reasons being:

  • When assigning your order, we match the paper’s discipline with the writer’s field/specialization. Since all our writers are graduates, we match the paper’s subject with the field the writer studied. For instance, if it’s a nursing paper, only a nursing graduate and writer will handle it. Furthermore, all our writers have academic writing experience and top-notch research skills.
  • We have a quality assurance that reviews the paper before it gets to you. As such, we ensure that you get a paper that meets the required standard and will most definitely make the grade.

In the event that you don’t like your paper:

  • The writer will revise the paper up to your pleasing. You have unlimited revisions. You simply need to highlight what specifically you don’t like about the paper, and the writer will make the amendments. The paper will be revised until you are satisfied. Revisions are free of charge
  • We will have a different writer write the paper from scratch.
  • Last resort, if the above does not work, we will refund your money.

Will the professor find out I didn’t write the paper myself?

Not at all. All papers are written from scratch. There is no way your tutor or instructor will realize that you did not write the paper yourself. In fact, we recommend using our assignment help services for consistent results.

What if the paper is plagiarized?

We check all papers for plagiarism before we submit them. We use powerful plagiarism checking software such as SafeAssign, LopesWrite, and Turnitin. We also upload the plagiarism report so that you can review it. We understand that plagiarism is academic suicide. We would not take the risk of submitting plagiarized work and jeopardize your academic journey. Furthermore, we do not sell or use prewritten papers, and each paper is written from scratch.

When will I get my paper?

You determine when you get the paper by setting the deadline when placing the order. All papers are delivered within the deadline. We are well aware that we operate in a time-sensitive industry. As such, we have laid out strategies to ensure that the client receives the paper on time and they never miss the deadline. We understand that papers that are submitted late have some points deducted. We do not want you to miss any points due to late submission. We work on beating deadlines by huge margins in order to ensure that you have ample time to review the paper before you submit it.

Will anyone find out that I used your services?

We have a privacy and confidentiality policy that guides our work. We NEVER share any customer information with third parties. Noone will ever know that you used our assignment help services. It’s only between you and us. We are bound by our policies to protect the customer’s identity and information. All your information, such as your names, phone number, email, order information, and so on, are protected. We have robust security systems that ensure that your data is protected. Hacking our systems is close to impossible, and it has never happened.

How our Assignment Help Service Works

1. Place an order

You fill all the paper instructions in the order form. Make sure you include all the helpful materials so that our academic writers can deliver the perfect paper. It will also help to eliminate unnecessary revisions.

2. Pay for the order

Proceed to pay for the paper so that it can be assigned to one of our expert academic writers. The paper subject is matched with the writer’s area of specialization.

3. Track the progress

You communicate with the writer and know about the progress of the paper. The client can ask the writer for drafts of the paper. The client can upload extra material and include additional instructions from the lecturer. Receive a paper.

4. Download the paper

The paper is sent to your email and uploaded to your personal account. You also get a plagiarism report attached to your paper.

smile and order essay GET A PERFECT SCORE!!! smile and order essay Buy Custom Essay

Place your order
(550 words)

Approximate price: $22

Calculate the price of your order

550 words
We'll send you the first draft for approval by September 11, 2018 at 10:52 AM
Total price:
The price is based on these factors:
Academic level
Number of pages
Basic features
  • Free title page and bibliography
  • Unlimited revisions
  • Plagiarism-free guarantee
  • Money-back guarantee
  • 24/7 support
On-demand options
  • Writer’s samples
  • Part-by-part delivery
  • Overnight delivery
  • Copies of used sources
  • Expert Proofreading
Paper format
  • 275 words per page
  • 12 pt Arial/Times New Roman
  • Double line spacing
  • Any citation style (APA, MLA, Chicago/Turabian, Harvard)

Our guarantees

Delivering a high-quality product at a reasonable price is not enough anymore.
That’s why we have developed 5 beneficial guarantees that will make your experience with our service enjoyable, easy, and safe.

Money-back guarantee

You have to be 100% sure of the quality of your product to give a money-back guarantee. This describes us perfectly. Make sure that this guarantee is totally transparent.

Read more

Zero-plagiarism guarantee

Each paper is composed from scratch, according to your instructions. It is then checked by our plagiarism-detection software. There is no gap where plagiarism could squeeze in.

Read more

Free-revision policy

Thanks to our free revisions, there is no way for you to be unsatisfied. We will work on your paper until you are completely happy with the result.

Read more

Privacy policy

Your email is safe, as we store it according to international data protection rules. Your bank details are secure, as we use only reliable payment systems.

Read more

Fair-cooperation guarantee

By sending us your money, you buy the service we provide. Check out our terms and conditions if you prefer business talks to be laid out in official language.

Read more
error: Content is protected !!
Open chat
Need assignment help? You can contact our live agent via WhatsApp using +1 718 717 2861

Feel free to ask questions, clarifications, or discounts available when placing an order.
  +1 718 717 2861           + 44 161 818 7126           [email protected]
  +1 718 717 2861         [email protected]