Vol. 1, Issue 5 ‣ September 2024
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Back to Basics: Best Practices for
Plating Techniques used with Growth Promotion Testing
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When performing Growth Promotion on new batches of media, one of three plating techniques can be used: Spread Plate, Pour Plate, or Membrane Filtration. Each method aids in enumeration of the cells in the inoculum, but each is different in technique. Below we offer our Top 5 Best Practices for each plating method to help you ensure proper growth promotion of your agar media.
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Spread Plate Method Best Practices
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- Avoid the edge. Contact with the edge of the plate can introduce contaminates to the agar. Avoid touching the edge of the plate with the loop while streaking or inoculating the agar with the swab.
- Keep the agar dry. Make sure the agar plates are free of droplets of condensed moisture. If moisture is present, leave the plates at room temperature overnight or place them in a laminar flow hood to dry.
- Spread the inoculum evenly. Use a sterile spread such as a loop, T-shape spreader, or L-shape spreader to evenly distribute the inoculum over the surface of the agar. This will help the colonies be easily counted and prevent clumping.
- Keep the inoculum small. Larger volumes of inoculum will take longer to soak into the agar and may cause colonies to get stuck or grow on the edge of the Petri dish. Aim to use volumes of 0.1ml or less.
- Don’t use agar straight from the fridge. Pre-warm the agar plates to room temperature before use. Remove them from refrigerated storage a few hours to even the night before use to ensure they have equilibrated.
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Continue reading to discover best practices for the Pour Plate and Membrane Filtration methods. Learn how to avoid common pitfalls, achieve uniform colony growth, and optimize each technique for accurate results in growth promotion testing. Click below to dive deeper into these essential microbiological practices.
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Product Spotlight: Streamline Your Growth Promotion Testing with EZ-Accu Shot™
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Designed for effortless control microorganism management, EZ-Accu Shot™ provides reliable performance and reduces prep time for your lab.
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- Convenient: Instant dissolve pellets, no dilutions needed
- Accurate: Delivers 10-100 CFU per inoculum, traceable to reference cultures
- Flexible: 8-hour stability post-rehydration ensures workflow flexibility
- Certified Quality: ISO 17034 accredited reference material
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Simplify High-Volume Growth Promotion Testing with EZ-CFU™
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EZ-CFU™ provides ready-to-use reference cultures for fast, efficient, and reliable Growth Promotion Testing. A simple 1:10 dilution delivers consistent results, reducing prep time and effort.
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- Convenient: Delivers 10-100 CFU per inoculum after a quick 1:10 dilution
- Cost-Effective: 900+ tests per kit, ideal for high-volume labs
- Certified Quality: ISO 17034 accredited and meets USP/Ph. Eur./JP requirements
- Reliable: Strains are three passages or fewer from reference cultures
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Growth Promotion Testing - USP Chapter Strains
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Strains used for USP <60>
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Growth Promoting + Indicative:
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- Burkholderia cenocepacia
- Burkholderia cepacia
- Burkholderia multivorans
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- Pseudomonas paraeruginosa
- Staphylococcus aureus
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Strains used for USP <61>
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- Aspergillus brasiliensis
- Bacillus spizizenii
- Candida albicans
- Pseudomonas paraeruginosa
- Staphylococcus aureus
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Strains used for USP <62>
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- Candida albicans
- Clostridium sporogenes
- Escherichia coli
- Pseudomonas paraeruginosa
- Salmonella Typhimurium
- Staphylococcus aureus
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Strains used for USP <71>
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- Aspergillus brasiliensis
- Bacillus spizizenii
- Candida albicans
- Clostridium sporogenes
- Pseudomonas paraeruginosa
- Staphylococcus aureus
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Reference: United States Pharmacopeia <60>, <61>, <62>, <71>
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Catalog Spotlight: Microbiologics®
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The Microbiologics Pharma Catalog by Hardy Diagnostics provides a comprehensive list of quality control microorganisms and related products for pharmaceutical applications, ensuring compliance with industry standards and enhancing laboratory efficiency.
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PHARMACEUTICAL PRODUCT MANAGER
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Joelle Brackeen is the Pharmaceutical Product Manager at Hardy Diagnostics and has over a decade of experience in Marketing and Product Management. Before transitioning to the pharma sector, Joelle had the privilege of co-founding and helping to grow a business into a highly profitable, multinational enterprise. Her unique blend of entrepreneurial spirit and product management expertise contributes to her innovative approach and ability to drive successful products and strategic initiatives in the pharmaceutical industry. In her free time, she enjoys playing the piano and spending time at the beach.
Do you have a suggestion, comment, or question? Please contact Joelle here.
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"A Culture of Service"
Hardy Diagnostics, 1430 West McCoy Lane, Santa Maria, CA, 93455, USA, +1.800.266.2222
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