Microbiology - Science topic

Agree with Yannick. However, some antibodies work for both WB and imaging applications. A relatively easy way to test a primary ab for imaging is usually by light (fluorescence) microscopy, using applicable secondary ab (fluorophor conjugated). Also keep in mind that most ab do not bind after fixation with standard glutaraldehyde concentrations used for EM.

It will be classic but you mentioned using a 30-minute reaction time, consider extending it slightly, as sometimes longer incubation times can improve RPA results, especially when using DNA extracted from complex samples. While 400 nM is a typical primer concentration for RPA, you can try titrating the primer concentration to optimize the reaction. Sometimes, higher or lower concentrations may work better depending on your specific setup. While the primers worked well in PCR, they might not be optimized for RPA. You could consider redesigning the primers specifically for RPA conditions. RPA primers may have different requirements, such as longer lengths (usually 30-35 bases) and specific GC content. First things that come to my mind. Good luck.

Revered Dr.Andrea Celeste Arismendi Sosa,

Hope you are from developed countries of Europe.

I came across these top ranked Scopus Indexed Journals are mostly waive off for third world countries stakeholders than others.

I have some list of free Scopus Indexed Journals that I will attach to your email ID.

Since you are from Microbiology that I will find some free Journals in your field of study.

Be in touch with my email ID drsenapathy@gmail.com

I will send in the returning mail reply.

Regards

Senapathy

Ethiopia

This is a recall be Remel based on failure of their microbiological medium to achieve excepted results. Again - Bio-Rad's produict is also a medical device used to diagnose disease. Your results indicate a problem and they're blowing it off. Suggest you file a complaint the FDA. They can detyermine if this is serious.

According to the European Committee on Antimicrobial Susceptibility Testing, inoculation agar plates, should be at room temperature before inoculation. The first 15 minutes is about the usage of adjusted inoculum suspension within 15 minutes of preparation. The second 15 minutes state that the disks should be applied within 15 minutes of inoculation because if it is left at room temperature for a long period before disks are applied, the organism might begin to grow which will result in an erroneous reduction in sizes of inhibition zone diameters. With that being stated, according to Anna King and Derek F.J. Brown in their journal entitled Quality Assurance of Antimicrobial Susceptibility Testing by Disc Diffusion, if the problem includes too large or too small zone diameters with all antimicrobials, the following should be observed:

1. Depth of agar should be checked, if it is incorrect, the amount of agar should be adjusted.

2. Inoculum size should be checked.

3. Ensure that the discs are applied to the inoculated plates within 15 minutes and that the plates are incubated within 15 minutes of the application of the discs.

The inclusion of the 15-15-15 rule in the troubleshooting controls proves that it is done to reduce errors in susceptibility testing in disc diffusion.

I don't think it matters whether you do your assays in 96 well plates, 24 well plates or tubes. But if you can not measure optical density or turbidity, then the easiest thing may be to measure surviving CFUs. You can plate out a sample of the culture after treating, but you might need to also do a dilution series. You can just do a series of 10 fold dilutions and spot 5 ul of each onto your plates (you can usually get a number of spots per plate). Otherwise plating directly after 24 hours is likely to have too high a cell density to count directly, unless the compound is highly inhibitory.

Why are so many methods and no answers the same? Other papers also mention the different results. What is actually the correct answer?

It all comes down to chemistry. The colder it is the slower chemical reactions happen (especially endothermic reactions). So yes storing your aliquots at -80ºC will prolong their shelf life compared to -20ºC but you will also need to factor in cost since colder freezers chew more power so are more expensive to run. This means you need to offset the cost of just buying in a new batch of antibiotics over the cost of keeping them colder.

Another factor you should consider is how the antibiotics degrade. Usually this is by oxidation so you can prolong the shelf life further by purging the atmosphere in the aliquot with argon or nitrogen. Note this would then need screw top vials since regular Eppendorfs are not great at preventing gas exchange.

Dear Dr Hasi,

Hope you're in good health.

After adding the name of the author in TOC, Elsevier will send the link directly to the author.

And then he or she is able to login in EMSS.

Please let me know if you have any questions

Thanks for your time and support

With warm regards

DEAR DR EVIEN

Certainly, preparing hydroxyapatite (HA) nanoparticles involves several steps, and it's important to have a clear understanding of the process to ensure successful synthesis. Hydroxyapatite is a biocompatible material often used in various biomedical and dental applications. Here's a general outline of the synthesis process:

1. Chemical Precursors:You'll need calcium and phosphate sources as your main precursors. Common choices are calcium nitrate or calcium chloride for the calcium source, and diammonium hydrogen phosphate or ammonium dihydrogen phosphate for the phosphate source.

2. Mixing:Dissolve the calcium and phosphate precursors in deionized water separately to create two solutions. Then, add the phosphate solution dropwise into the calcium solution under constant stirring. This will lead to the precipitation of hydroxyapatite.

3. pH Adjustment:The pH of the mixture is critical for obtaining pure hydroxyapatite. Adjust the pH to around 9-10 using a base (like ammonium hydroxide or sodium hydroxide) to promote HA formation.

4. Aging:Allow the mixture to age for a certain period, typically several hours to overnight. During aging, the nanoparticles will grow and form stable structures.

5. Filtration and Washing:After aging, the precipitate is usually separated by filtration and washed with deionized water to remove any residual chemicals and impurities.

6. Drying:Dry the obtained precipitate in an oven at a temperature around 60-80°C. This will result in the formation of hydroxyapatite nanoparticles.

In addition to Phil Geis question, in what subspecialty. There are hundreds or perhaps even thousands of microbiology journals but many are specialized, for example in pathogenesis or clinical microbiology, environmental, industrial, molecular genetics, etc

By culturing in bacterial culture media

The microbiolgical quality in the pharmocopia kept a modern apothecary " natural body care"

Dear doctor

Go To

Association between atopic dermatitis and serious cutaneous, multiorgan and systemic infections in US adults

Shanthi Narla, and Jonathan I. Silverberg,

Ann Allergy Asthma Immunol. 2018 Jan; 120(1): 66–72.e11.

doi: 10.1016/j.anai.2017.10.019

"Introduction

Atopic dermatitis (AD) is a chronic inflammatory skin disease affecting 13% of children1 and 7–10% of adults across the United States. It is well established that AD is associated with a higher incidence of certain cutaneous infections, including Staphylococcus aureus colonization, molluscum contagiosum and eczema herpeticum (EH), and possibly cutaneous warts. In fact, predisposition toward cutaneous infection is one of the Hanifin and Rajka minor diagnostic criterion for AD8. The mechanism of such predisposition is thought to be multifactorial, including impaired epidermal barrier function9, decreased expression of antimicrobial peptides, and abnormal innate immune response in skin.

Recent US population-based studies showed that AD is also associated with higher rates of extra-cutaneous infection in both children and adults, such as infections of the upper and lower respiratory tracts, ears and urinary tract. Those studies utilized surveys with questions about self- or caregiver-reported AD and infections. In the present study, we sought to determine whether there is an association between healthcare diagnosed AD and serious infections in adults. We hypothesized that adults with AD have significantly higher prevalences of cutaneous, respiratory, multi-organ and systemic infections.

In conclusion, adults with AD had significantly higher odds of cutaneous, respiratory, multi-organ and systemic infections. Serious infections were associated with a substantial financial-burden in patients with AD."

I am interested in initiating a bilateral project, here are some general steps you can follow:

Bonjour,

Pour le moment tous nos projets sont pris par les doctorants.

Cordialement. M. SIDQUI

Binyamin Kerman very kind for your answer, thanks. Exploring all your suggestions!

N

Certainly! When it comes to digital microscopes for microbiology, there are several options available. Here are a few recommendations that are commonly used for observing molds:

1. Celestron 44341 LCD Digital Microscope: This microscope features a built-in LCD screen and a 2-megapixel camera. It provides magnifications of up to 200x and has built-in LED illumination. It's portable and easy to use, making it suitable for mold observation.

2. Dino-Lite AM4113T Digital Microscope: This microscope offers a higher resolution with a 1.3-megapixel camera and magnifications up to 200x. It also includes built-in LED lights for illumination. The Dino-Lite series is well-regarded for its quality and versatility.

3. OMAX 40X-2000X Digital Binocular Microscope: If you're looking for higher magnifications, this binocular microscope from OMAX is a good option. It comes with a built-in 1.3-megapixel camera and includes multiple objectives for magnifications ranging from 40x to 2000x. It also has a mechanical stage for precise specimen positioning.

4. Levenhuk DTX 500 Mobi Digital Microscope: This portable microscope offers magnifications of up to 500x and includes a 1.3-megapixel camera. It has eight built-in LED lights for illumination and can be connected to a computer or smartphone for image capture and analysis.

Remember to consider your specific requirements, such as budget, desired magnification range, portability, and connectivity options, when choosing a digital microscope for your microbiology needs. It's also a good idea to read customer reviews and compare features before making a purchase to ensure it meets your expectations.

1. Adjust primer length: Increase or decrease primer length slightly.

2. Evaluate Tm prediction methods: Use different algorithms or tools for Tm calculation.

3. Adjust primer sequence: Make small modifications to fine-tune Tm.

4. Check for secondary structures: Identify and minimize hairpins or self-complementarity.

5. Consider primer placement: Avoid repetitive or variable regions.

6. Follow primer design guidelines: Adhere to established recommendations.

7. Validate and test primers experimentally.

Dear Sudeep Poudel The impact factor as indicated by Phil Geis is legit. Since June 2023 Clarivate assigned journals indexed in their ESCI an impact factor, as announced for example here https://clarivate.com/blog/mapping-the-path-to-future-changes-in-the-journal-citation-reports/

The journal is as indicated in their own indexing info https://www.hindawi.com/journals/ijmicro/ai/ still indexed in Clarivate’s Emerging Sources Citation Index (ESCI) and has an impact factor of 3.4

Best regards.

PS. Unfortunately nobody here on RG seems to have the JCR report list with the IF of all ESCI titles (yet).

yes it looks contaminant

For spray dryer -after heat treatment - does water remain and what are the microbes recovered?

Could you please share with us how you isolated the Nitrosomonas bacteria?

tank you

Do you mean The Algerian society of clinical microbiology (société algérienne de la microbiologie clinique SAMiC) ?https://www.samic.dz/site/index.php

Don't know either. Just an idea.

As Phil Geis mentions it might be due to the level of use of antibiotics in those regions. However another possibility might be that screening for MDR and XDR is not as prevalent in developing regions so we don't know the actual levels due to insufficient screening for it.

The fluorescence is caused by pyoverdines which are iron scavenging siderophores. The difference in colour can be caused by differences in ion binding and structure of the compounds at either a synthesis (https://microbialcell.com/researcharticles/the-biosynthesis-of-pyoverdines/) or degradation ( ) level. Potentially one of your antibiotics is inhibiting a step in the synthesis pathway or is changing the pH of the cell.

Vaccinology is a broad term of sciences dealing manufacuring vaccine which licenced after sucessful expermental researches on efficacy, safety and economic consedartions.

Assessing diversity metrics in 16S data is an important step in analyzing microbial communities. Handling count data in this context can be challenging due to the compositional nature of the data, as you mentioned. While there is no one-size-fits-all approach, there are several techniques and considerations you can explore. Here are some suggestions:

Remember that there is ongoing research in the field, and best practices continue to evolve. It's important to critically evaluate the methods, consider the specific characteristics of your data, and consult with your advisor or peers with expertise in microbiome analysis to make informed decisions about data transformations and diversity metric assessment.

Don't forget that the transcription start site might be very far away from the ORF, especially if the ORF is part of an operon. So don't just look immediately upstream from the ORF.

There could be several possible reasons why no bands are observed in the PCR amplification of 16S rRNA of E.coli genes:

These video playlists might be helpful to you:

The decimal reduction dose (D-value) is a measure of the effectiveness of a non-linear logarithmic reduction treatment, which is typically used in microbiology to determine the amount of radiation, heat, or chemical treatment needed to reduce the number of microorganisms by 90%. The D-value is calculated using the following formula:

D = (log N0 - log N1) / k

Where:

- D is the decimal reduction dose (in the unit of the treatment)

- N0 is the initial number of microorganisms

- N1 is the number of surviving microorganisms after treatment

- k is the slope of the logarithmic reduction curve (also known as the "death rate constant")

To calculate the D-value, you will need to perform a series of experiments where you expose a known number of microorganisms to different doses of the non-linear logarithmic reduction treatment, and then count the number of surviving microorganisms at each dose. You can then plot the data on a logarithmic scale, and determine the slope of the curve using linear regression analysis.

Once you have the slope (k) of the logarithmic reduction curve, you can use the above formula to calculate the D-value for a given treatment. For example, if you have determined that the D-value for a particular radiation treatment is 10 kGy, then you would need to apply a dose of 10 kGy to achieve a 90% reduction in the number of microorganisms.

Note that the calculation of the D-value assumes that the reduction in microorganisms is a stochastic process that follows a logarithmic distribution. The actual reduction may be affected by other factors, such as the age and physiological state of the microorganisms, the presence of protective materials, and the environmental conditions during treatment.

Ali Safaa

1.Pyocyanin can be adsorbed on the surface of gold nanoparticles. It does not oxidize or reduce gold. Gold is oxidized with potassium cyanide or aqua regia.

2. When interacting with gold ions, Pyocyanin (quinone) acts as an oxidizing agent.

3. Pyocyanin melting point 133 0С.

Dear Diana,

I think that all of the answers above are reasonable but none have mentioned directly another factor – what is the air quality like in your laboratory? I have worked in university labs in warm and humid places, where mould was always a problem, in which case a laminar flow cabinet with a good filter would be very useful, and in colder drier places where we never seem to have problems with air-born spores, and where a bunsen that can be moved around to suit may be a better option.

Andrew

As far as I know, to ensure the safety of water, we need a combination between filtration and chemical treatments, first with ozone as a very strong oxidizing agent, then filtration using biological activated carbon to get rid of oxidation residues, which may constitute good nutrients for the remaining bacteria, causing rapid growth and thus water pollution. ... Then chlorination to eliminate the remaining harmful microorganisms...My sincere gratitude to everyone.

Emergence has become the front and center of my research in the couple of last years. To be capable to understand its working in depth, I had developed several open-source Python programs (ranging from the simplest one to the most advanced one) that enables everyone first to understand the cellular automata programming, and later apply them to studies of emergence that is occurring in so-called 'Game of Life'.

Quite a few videos depicting animated emergent structures are accessible in my profile at sections about data and software: e.g., logic-gates AND, OR, NOT, and quite a few emergent structures emerging in generalized neighborhoods of the original GoL. The latest paper is describing another interesting area, the design of error-resilient emergents, which can withstand the of 1% of errors into their evaluation process.

With respect to the questions provided in this answer. I highly recommend watching said videos and even run the open-source GoL-N24 Python software and try to play with emergence on your own. The personal experience with those simulations is always the best way to start to understand that we do not understand the theory of emergence!

Everyone is welcomed to play with emergence. One thing is sure, there are hiding huge treasures both experimental and theoretical in such 'playing' with the concept of emergence. Hopefully, this year will be published a paper that is going to address, at least, some root questions about emergence and its very principles (stay tuned).

References:

https://www.researchgate.net/publication/355043921_The_simplest_Python_program_simulating_a_cellular_automaton_model_of_a_complex_system_the_'Game_of_Life'

https://www.researchgate.net/publication/356759719_Computer_Components_Simulated_Using_the_'Game_of_Life'_cellular_automaton_logic_gate_AND

There are all three logic-gates avaiable

https://www.researchgate.net/publication/357285926_Python_program_simulating_cellular_automaton_r-GoL_that_represents_robust_generalization_of_'Game_of_Life'_sample_runs

https://www.researchgate.net/publication/361818826_Robust_massive_parallel_information_processing_environments_in_biology_and_medicine_case_study

Dear Saad Al-Arnoot

Yes, it could be cytotoxic depending on its concentration and less than 1% is mainly recommended in a working solution.

https://www.sciencedirect.com/science/article/abs/pii/S0022354915369057

Yes, it is possible to use Nile Red instead of EtBr for the cartwheel assay to detect efflux pumps. Nile Red is a lipophilic dye that can be used to monitor changes in the hydrophobicity of bacterial membranes, which is associated with efflux pump activity.

The concentration of Nile Red in the plates should be optimized for the particular bacterial strain being tested. A concentration of 0.5 mg/L may be appropriate for some strains, but others may require a higher or lower concentration. You may need to perform a dose-response experiment to determine the optimal concentration for your bacterial strain.

Using broth for the assay may not be the most suitable approach for all bacterial strains. The composition of the growth medium can affect the expression and activity of efflux pumps. You may want to try using solid media instead, such as Mueller-Hinton agar, which is commonly used for MIC assays. The bacterial cells can be inoculated onto the agar surface and then incubated with the Nile Red-containing media.

Additionally, you may want to consider using a positive control strain that is known to express efflux pumps, to ensure that the assay is working properly. Finally, it is important to interpret the results of the assay carefully, as there may be other factors that can affect the fluorescence of the cells, such as changes in membrane potential or alterations in membrane composition.

The three domains are the archaea, the bacteria and the eukarya. prokaryotic organism belong either to the domain archaea or the domain bacteria,organism with eukaryotic cells belong to the domain eukarya.

The three domains of life employ various strategies to organize their genomes. Archaea utilize features similar to those found in both eukaryotic and bacterial chromatin to organize their DNA. The current state of research regarding the structure function relationships of several archaeal chromatin proteins histones, Alba, cren7 and Sul7d.

Microorganism transfer genes to other organisms through horizontal gene transfer -the transfer of rRNA or tRNA or DNA to an organism that is not its offspring.

Hi all,

Thank you for your answers,

I did a restriction digest with enzymes that cut multiple times and indeed, this plasmid has recombined in all sorts of ways except the one I was planning on...

I don't know if any of you have practiced recombineering before, but if you have I would really appreciate your advice regarding how to reduce unwanted recombination events in this type of cloning.

I am using an L-arabinose inducible plasmid for the λRed system. Are NEB10betas good cells for these protocols or maybe Stabl3 would be a better option? Also, would co-electroporating my plasmid at very low concentrations and the linear dsDNA into E. coli (which contains the induced λRed system-plasmid) help in avoiding these undesired recombinations?

Any other thoughts or help on how to avoid this?

Thanks!

I'm not sure if you are only interested in physical factors related to light.

However, another important physical factor in the cultivation of CHO cells in a shake flask / stirred tank reactors is the generated shear force. If you want to investigate this further - test different rpm and flasks with/without chicanes.

As far as light itself is concerned - keep in mind that light can also influence the culture medium and this could then indirectly influence the cells.

Dear Ali,

There are probably many ways you can differentiate bacterial biofilm formation and I'd suggest either following the procedure described in a research paper working on the species or strains you are interested in, or by using your own criteria. We characterise our air-liquid interface biofilms using a combined biofilm assay measuring biofilm strength, attachment levels and total growth - which means we can describe 'biofilms' using one or all three quantitative measurements. We tend not to use 'no biofilm' control strains, as many biofilm-formers produce such weak and poorly attached structures it is not clear when a 'no biofilm' becomes a measurable one (though we can use a sterile microcosm/culture as the negative control if appropriate).

I can't comment on your problems with Excel, but one simple way is to graph the mean results from your experimental replicates, and divide these into quartiles about the median (i.e., from the minimum values to Q1, from Q1 to the median, from the median to Q3, and from Q3 to the maximum value). You could then simply state that no or poor biofilm formers are min - Q1, biofilm formers are Q1 ≤ Q3, and good biofilm-formers are Q3 - max (if you liked, you could divide your bacteria into no biofilm, poor biofilms, good biofilms and very good biofilms – the number of categories is up to you, but you can't have lots when you have relatively few bacteria to distribute across these categories).

There are statistical tests you could use, and assuming that data (or residuals) are Normally distributed, you could say that no or poor biofilms are not significantly different to a no-biofilm control, etc., but this gets messy because it is hard to know when a very poor biofilm is effectively no biofilm, etc.

Andrew

@ Sjon, the attached file may be useful to you.

Hello, most studies have used Brucella agar or Columbia agar as the agar base. An amount of 7 to 10% blood improves the growth of H. pylori. Horse blood may also improve the growth of H. pylori as compared to sheep blood.

In fact the major mechanisms of action of probiotics is the regulation of host immune response. Thus, the immune system is divided into the innate and adaptive systems. The adaptive immune response depends on B and T lymphocytes, which bind to specific antigens. Some of the beneficial effects of probiotic consumption include improvement of intestinal health by the regulation of microbiota, and stimulation and development of the immune system, synthesizing and enhancing the bioavailability of nutrients, reducing symptoms of lactose intolerance. Probiotics Modulate Both Innate and Adaptive Immune System. One of the most powerful effects of probiotics is to modulate the immune system. Probiotics strengthen both innate and adaptive immune responses through bacterial-epithelial-immune cell crosstalk. By the provision of energy sources for gut microbiota, prebiotics are able to modulate the composition and the function of these microorganisms. Distant bacterial species in phylogeny share their skills to consume a specific prebiotic regularly. Prebiotics are specialized plant fibers. They act like fertilizers that stimulate the growth of healthy bacteria in the gut. Prebiotics are found in many fruits and vegetables, especially those that contain complex carbohydrates, such as fiber and resistant starch. The prebiotic atmosphere is the second atmosphere present on Earth before today's biotic, oxygen-rich third atmosphere, and after the first atmosphere of Earth's formation. The formation of the Earth, roughly 4.5 billion years ago, involved multiple collisions and coalescence of planetary embryos.

By using suitable filter

Membrane, I guess.

Generally I like to use 100-1000 fold dilution of the inoculum for the final culture volume. It is ok to go more dilute, really the main criteria should be how long you want to grow the final culture for.

Kseniya Kondrasheva Nikhita Madhav Chambhare Thank you very much, The Goal is Pyocyanin production, we tried 1:100 and yes by micropipette because the loop carry small volume

Book titled “Wastewater Engineering Treatment and Reuse” by MetCalf & Eddy is considered the Holy Bible for Wastewater treatment.

Dear Michael J. Benedik

You are totally right, it is mentioned in the guidelines of FDA and other agencies that the production strain must be validated through WGS and supplier's documents. However, unfortunately, both are unavailable at the moment. If the regulators do not accept this method, there is no option but to perform WGS.

What do your plates look like? Sometimes if you have a contaminant somewhere you get an unusual lawn and this hides the appearance of plaques. So is your lawn really nice and even and opaque over the entire plate?

Add Chloroform to a total of 50% total volume and vortex vigorously for a min or half. Let the sample settle for 10 minutes

The yeast Zygosaccharomyces rouxii is known for its high tolerance to osmotic stress, which is thought to be caused by sets of specific genes.

Yes @Daniil you can do email me

One thing I would add to Adam B Shapiro response is the % recovery during processing and fermentation. The final yield of enzyme is often a small fraction of the initial yield.

This is a scientefic and commercial subject ,so the only mean is coordination between your institute and intenational organizations like WHO,CDC ,FAO so ....on for scientfic side while commercial side follow an agreements of manufactury prducing

HI,

where are you from? Are you willing to travel?

This web site is filled with opportunities regarding what you are looking for:

A simple method:

Obtain a pure culture broth of P. aeruginosa.

Centrifuge the broth.

Separate the supernatant.

Add chloroform to the supernatant.

Keep it for settlement.

Add HCl. It will turns into pink/red. Again keep for settlement.

Add NaOH, it will turns blue.

Pigment isolated.

Plate No 4 contains Penicillium (blueish colony, Aspergillus paraciticus (dark green colonies), Fusarium (whitish colony), and Alternaira blackish colony)

Dear Harry,

We regularly make up King's B medium – Proteose peptone, glycerol, KH2PO4 and K2HPO4. To avoid precipitates, I always add the KH2PO4 and K2HPO4 to the deionised water and wait until that is dissolved, before adding the glycerol and peptone (and agar).

Andrew

Hello.

You should identify grown colonies on the MALDI-spectrometer. If it is the target microorganism, then the dilution should be rechecked.

No, it is not normal that after 3 weeks of freezing, the culture dies. Typically, long-term storage of P. aeruginosa stock cultures is carried out at -80ºC.

Sincerely yours,

Artem Trofimenko

Dear Fausto Cabezas ,

You might consider the well-renowned Max Planck Institute, see for example: https://www.age.mpg.de/science/core-facilities/bioinformatics

Best regards.

Hi, In Brazil, you can apply to these programs of Bioinformatics. We have so many other bioinformatics programs and other microbiology programs.

http://www.pgbioinfo.icb.ufmg.br (Registration starts on December 2022)

Good luck.

Kristova Yubilius Indrataruna I have two suggestions for you: 1) Use ASNIII medium for marine CB: BG-11 was elaborated for freshwater CB; 2) Use very purified agarose (like Kim Sea) instead of either agar or gellan gum because very purified agarose does not support the proliferation of heterotrophs. Good luck. Igor Brown

You may also consider precipitation/crashing of compound at higher concentration also.....which will make it unavailable to cells, if that is case.

Hope that helps!

The question does not have enough details. Is the problem that the strain does not grow at all in SC and SCEG? Or that the data is not reproducible, or the curves don't look correct? Those are all very different sorts of problems.

Simplifying

Cosmetic micro specs include two elements;

1) Total count. Some reg's recognize two of these - one for kids and eyes (to to 500/ml or g) and another for general products (up to 1000 cfu/ml or g. Major industry works at 100 cfu/ml or g.

2) Objectionable microbes. For health concerns, no detection of Staphylococcus aureus, Pseudomonas aeruginosa or Candida albicans is universal. Some reg's add Enterococcus. Many add Burkholderia cepacia complex. Major cosmetic companies specify no staph or candida as above and no detected Gram negative bacteria.

Hi Twana,

The total mesophilic plant count will be unsuitable in case of fermented food as there are chances of mesophilic contaminants active in the fermented food if kept in exposure to contamination or the result of poor quality control while the packaging David Sturm has answered nearly the exact same answer. It can also be understood by a condition that while the food sample has been a fermented product and the time the other mesophilic contaminant was inactive due to certain reason and with due course of time after a certain time limit the microbe dominating the fermented food might start producing metabolites that other contaminant can consume. Although microbe in the food sample present in its packaging it can be slow but while being the mesophilic and getting the nutrient from the plate itself it has a good chances of experiencing a better growth then in the food itself.

Hope this might clear your doubt,

Best Regards