– A thermo-chemical disinfection process is tested using three cultures of vegetative bacteria:- Staphylococcus aureus, Streptococcus faecalis and Escherichia coli in suspension against the disinfectant ‘X ’ at a concentration of 50 mg/l. The results are given in the Table below. ‘Zero’ exposure time refers to the suspension before exposure to temperature/chemical conditions. An inactivator, established as effectively quenching the disinfectant without (either alone or with the reaction products from interaction with the disinfectant) affecting the growth and recovery of any of the organisms tested, was used.
(I) Plot inactivation curves for each set of results.
(ii) What explanation can you offer for the shapes of the inactivation curves?
(iii) Select appropriate data to determine the D values* for each organism,
giving reasons for your choice.
(iv) Calculate the D values and comment briefly
I would like to know if somebody will be able to rewrite my assessment following the feedback:
“The answer begins with an error – the inactivation curve is not done by “ plotting temperature against time”, the cited references do not state that and this is not how you presented the data. It is a plot of population v time for a specified temperature.
The incorrect formula has been used for the D value – the references listed include a number of sources that would have given the correct version. Consideration of the D value definition would have shown that the formula had been inverted.
You have not used a log /linear plot for the inactivation curve. In consequence the population scale was 5,000,000 cfu steps, thus most data points could not be differentiated. Spurious significance appears to have been on the shape of the curve at 1min and 2 min – although this is described as 1 degree of temperature and 2 degree temperature. Regrettably, the text is utterly incomprehensible.
In response to 1b (iii), you have correctly stated that “using log to base 10 the data becomes linear” and this has been applied to the calculations. The calculations were all arithmetically correct and marks have not been deducted for using the wrong formula in these calculations.
The units for D values are incorrect – by giving log10 values, this converts the population to a number rather than remaining as cfu/ml. The D value is then stated in minutes, with the specific temperature given as a subscript eg T35.”
Comments from Support Team: Discipline: Scientific Principles underlying Decontamination Hospital sterile services
Our Service Charter
Excellent Quality / 100% Plagiarism-FreeWe employ a number of measures to ensure top quality essays. The papers go through a system of quality control prior to delivery. We run plagiarism checks on each paper to ensure that they will be 100% plagiarism-free. So, only clean copies hit customers’ emails. We also never resell the papers completed by our writers. So, once it is checked using a plagiarism checker, the paper will be unique. Speaking of the academic writing standards, we will stick to the assignment brief given by the customer and assign the perfect writer. By saying “the perfect writer” we mean the one having an academic degree in the customer’s study field and positive feedback from other customers.
Free RevisionsWe keep the quality bar of all papers high. But in case you need some extra brilliance to the paper, here’s what to do. First of all, you can choose a top writer. It means that we will assign an expert with a degree in your subject. And secondly, you can rely on our editing services. Our editors will revise your papers, checking whether or not they comply with high standards of academic writing. In addition, editing entails adjusting content if it’s off the topic, adding more sources, refining the language style, and making sure the referencing style is followed.
Confidentiality / 100% No DisclosureWe make sure that clients’ personal data remains confidential and is not exploited for any purposes beyond those related to our services. We only ask you to provide us with the information that is required to produce the paper according to your writing needs. Please note that the payment info is protected as well. Feel free to refer to the support team for more information about our payment methods. The fact that you used our service is kept secret due to the advanced security standards. So, you can be sure that no one will find out that you got a paper from our writing service.
Money Back GuaranteeIf the writer doesn’t address all the questions on your assignment brief or the delivered paper appears to be off the topic, you can ask for a refund. Or, if it is applicable, you can opt in for free revision within 14-30 days, depending on your paper’s length. The revision or refund request should be sent within 14 days after delivery. The customer gets 100% money-back in case they haven't downloaded the paper. All approved refunds will be returned to the customer’s credit card or Bonus Balance in a form of store credit. Take a note that we will send an extra compensation if the customers goes with a store credit.
24/7 Customer SupportWe have a support team working 24/7 ready to give your issue concerning the order their immediate attention. If you have any questions about the ordering process, communication with the writer, payment options, feel free to join live chat. Be sure to get a fast response. They can also give you the exact price quote, taking into account the timing, desired academic level of the paper, and the number of pages.