HomeMicrobiologyDe-complicating Incoming Inspection of Prepared-to-Use Cultures

De-complicating Incoming Inspection of Prepared-to-Use Cultures

Once you obtain a cargo of ready-to-use cultures, guaranteeing their suitability to be used in your laboratory doesn’t must be difficult! On this weblog we’ll go over what to examine and find out how to take a look at for fulfillment.

In line with USP <1117>, “Prepared-to-use cultures ought to be subjected to incoming testing for purity and id earlier than use. The affirmation of id for generally used laboratory strains ought to ideally be completed on the degree of genus and species.” Moreover this requirement from the pharmacopeia, additionally it is vital to make sure that the product is assembly the producer’s specs as effectively.

Restoration and Producer’s Guarantee

Earlier than utilizing your ready-to-use cultures, it is very important know and perceive the producer’s guarantee. Though every ready-to-use tradition could also be designed to work for a selected take a look at, akin to Development Promotion Testing (GPT), not all are warranted to get well or carry out the identical approach. Start by finding the Directions for Use for the ready-to-use tradition you might have chosen. Learn it by means of rigorously and be sure to perceive the guarantee and find out how to use the product. If in case you have any questions, at all times attain out to their Technical Help groups! Subsequent, collect all of the supplies you should set-up the product to be used; additionally it is acceptable to carry out GPT similtaneously incoming inspection, particularly if you’re testing in parallel with a beforehand accredited lot of media and a brand new lot of media.

Within the case of GPT, the counts on the beforehand accredited lot might be used to:

  • Verify the ready-to-use tradition is assembly producer’s guarantee
  • Confirm the tradition delivers not more than 100 CFU to be compliant with pharmacopeial necessities
  • Present the usual for calculating the issue of two restoration vary for GPT

It may be very tempting to make use of the restoration reported on the Certificates of Evaluation (CoA) as an alternative of counts on a beforehand accredited lot of media to calculate the issue of two restoration vary. Remember, nevertheless, that the values the producer offers on the Certificates of Evaluation (CoA) and even product labeling are the numbers obtained on the manufacturing facility. The strategies and supplies they use might not be the identical as these in your laboratory, which introduces a brand new variable to your GPT. For GPT, it is very important decrease experimental variables so you possibly can concentrate on the one variable you are attempting to measure: Media Efficiency.

Upon getting verified that the product is delivering the proper focus for GPT or different exams, in addition to assembly the producer’s guarantee, you now want to verify the tradition’s id.

Identification and Purity

As soon as the tradition is grown, now you can carry out identification exams to verify the tradition supplied to you is what’s claimed on the label. Per the USP and different pharmacopoeias, identification ought to be completed at a minimal to the genus degree. Nonetheless, if doable, identification to the species degree will offer you extra data relating to the pressure’s id.

For identification, there are lots of several types of exams that may be completed to verify the id. USP <1113> Microbial Characterization, Identification, and Pressure Typing can be utilized that will help you decide what varieties of applied sciences to implement to verify the id. Per this chapter and relying on the pressure, a number of of the next classes of exams and applied sciences will be employed:


  •  Morphological
    • Statement of the colony morphology on agar plates and microscopically
      • Is the Gram response right for the pressure on the label?
      • Do the colonies have the correct form or colour on a selected agar sort?
  • Physiological
    • Oxygen tolerance
    • Optimum temperature ranges
  • Biochemical exams
    • Carbohydrate oxidation or fermentation, enzyme patterns, and carbon utilization
      • API Strips
      • Vitek 2 Panels
    • MALDI-TOF Mass Spectrometry
    • Fatty acid profiles by gas-liquid chromatography


  • DNA base ratio (G + C content material)
  • DNA hybridizations


  • Alignment of 16s or 23s rRNA sequences of the ready-to-use tradition with identified sort pressure sequences
  • DNA – DNA hybridization

It goes with out saying that every methodology you employ for identification ought to be verified to make sure health to be used, accuracy, and reproducibility.


Upon getting confirmed the pressure’s id and its conformity to the producer’s guarantee and necessities of the pharmacopoeia, you might be prepared to make use of it in your laboratory!

Prepared-to-use & easy-to-use

To make this course of even simpler on the laboratory workers, select effectively established and revered ready-to-use cultures, akin to Microbiologics’ EZ-Accu Shot™ merchandise. For extra data, go to our web site at: https://www.microbiologics.com/item-type/Product/product-format/EZ-Accu-Shot



<1113> MICROBIAL CHARACTERIZATION, IDENTIFICATION, AND STRAIN TYPING. (2020). In United States Pharmacopeial Conference Committee of Revision (Ed.), USP-NF On-line (forty third ed.). United States Pharmacopeial Conference.

<1117> MICROBIOLOGICAL BEST LABORATORY PRACTICES. (2020). In United States Pharmacopeial Conference Committee of Revision (Ed.), USP-NF On-line (forty third ed.). United States Pharmacopeial Conference.




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