Aseptic Culture Inoculation
When working with any microorganism, or any sample that may contain microorganisms, it is important to work aseptically. This video demonstrates how to inoculate yeast from solid into liquid medium using aseptic technique. The ability to perform this correctly is important in any brewing laboratory, minimizing the risk of contamination from wild yeast, bacteria, and molds, while allowing for consistency from batch to batch.
Pouring Agar Plates
This video introduces the concept of preparing agar plates by pouring culture medium into a sterile petri dish and allowing it to solidify in a sterile environment. This technique is important for many basic microbiological analyses within the quality-control laboratory, such as for the detection of microorganisms in beer or process samples or for the preparation and short-term storage of yeast cultures.
Notes: In this video, a Bunsen burner is used to produce a sterile environment. However, a sterile laminar-flow cabinet or equivalent can also be used. If neither of these pieces of equipment is available, it is important to ensure that the work surface and the poured plates are microbiologically clean. This can achieved by wiping surfaces with 70% ethanol and immediately replacing the lid of the petri dish after pouring. In this instance, to avoid condensation buildup, plates should be places in an incubator for 24 h to dry sufficiently prior to use. This method may also serve as a rough check to ensure that poured plates are not contaminated with fast-growing organisms. Irrespective of the mode of preparation, prepared plates should be stored at 4°C for no longer than 2 weeks prior to use.
This video introduces the concept of preparing volumes of liquids using measuring cylinders. This is important for a range of operations, including the preparation of microbiological growth media, general laboratory solutions, and other volumes of liquid. Although this method is precise, it is best applied when a high level of accuracy is not required or for working with large volumes (>20 mL).
This video describes how small volumes of liquids (<10 mL) can be dispensed with automatic pipettes, which can save time and prevent repetitive strain injury to users handling multiple samples. Automatic pipetting provides an advanced level of precision and is suitable for procedures in which a high degree of accuracy is required, such as preparing chemical solutions, performing molecular biological techniques, or adding supplements to microbiological media.
Using Volumetric Flasks
An instructional video demonstrating the proper way to measure liquids in a volumetric flask. Proper use of a volumetric flask is a valuable skill in the laboratory. Volumetric flasks are often used when completing tasks such as preparing standards for calibrations and preparing serial dilutions or when precise measurement of a liquid is necessary. Upon watching this video, one should be able to accurately use a volumetric flask with precision and confidence.