Common microbial contamination in foods - Ohaus assists food safety (2)
Meso Injection,Hyaluronic Meso Injection,No Needle Hyaluronic Meso Injection,Injection No Needle Meso Jiangsu Tiera Biotechnology Co., Ltd , https://www.tierabio.com
A microbial cell continuously absorbs nutrients under appropriate external conditions and metabolizes according to its own metabolism. If the rate of assimilation exceeds the dissimilation effect, the total amount (weight, volume, size) of the protoplasts increases continuously, and the individual growth phenomenon occurs. If this is a balanced growth, that is, each cell component grows in an appropriate proportion, then when it reaches a certain level, it will multiply, causing an increase in the number of individuals. At this time, the original individual has developed into a group. . As the individual grows in the population, this group is caused to grow, which can be measured by its volume, weight, density or concentration. 
The growth of microorganisms is different from the growth of other organisms. Individual growth of microorganisms has certain difficulties in scientific research, and usually has no practical significance. Microorganisms are harvested in quantity, and therefore, the growth of microorganisms generally refers to the expansion of the population. The growth and reproduction of microorganisms is a comprehensive reflection of the interaction of various environmental factors inside and outside. Therefore, growth and reproduction can be used as an important indicator to study various physiological, biochemical and genetic problems. At the same time, the various applications of microorganisms in production practice or the prevention and treatment of pathogenic and mildew microorganisms are closely related to their growth inhibition. . Therefore, it is necessary to introduce the detection method of microbial growth. Since growth means an increase in the content of protoplasts, the methods of determination are also based on direct or indirect basis, and the determination of reproduction is based on counting. The measurement of microbial growth can be measured by its weight, volume, density, concentration, and indicators.
Volume measurement method: also called the method for measuring the concentration of mycelium.
The growth of microorganisms is reflected by measuring the amount of hyphae in a volume of medium. The method is to take a certain amount of medium (such as 10ml) into a calibration centrifuge tube, set a certain centrifugation time (such as 5 minutes) and speed (such as 5000_rpm). After centrifugation, the supernatant was decanted, and the volume of the supernatant was determined to be v, and the mycelium concentration was (10-v)/10. Determination of mycelial concentration is an important monitoring indicator for microbial growth in large-scale industrial fermentation production. This method is simple and fast, but requires the same processing conditions to be set. Otherwise, the deviation is very large. Due to the presence of some solid nutrients in the centrifuged sediment, the results are biased. 
Dry weight method:
It can be determined by centrifugation or filtration. Generally dry weight is 10-20% of wet weight. In the centrifugation method, a certain volume of the culture solution to be tested is poured into a centrifuge tube, a certain centrifugation time and a rotation speed are set, centrifuged, and washed with water for 1-5 times, and dried. Drying can be dried at 105 ° C or 100 ° C in an oven, or dried in infrared, or vacuum dried at 80 ° C or 40 ° C, and then weighed after drying. If the filtration method is used, the filamentous fungus can be filtered with a filter paper, and the bacteria can be filtered with a filter membrane such as a cellulose acetate membrane, filtered, washed with a small amount of water, and vacuum dried at 40 °C. The dry re-issue method is more cumbersome. When the microbial products obtained are usually bacterial cells, this method is often used, such as active dry yeast (ADY), and some feeds and fertilizers using microbial cells as active substances.
The above two methods are inseparable from the role of the centrifuge. Laboratory centrifuges are instruments that use centrifugal force generated by a rotating rotor to separate substances of different densities and different particle sizes in a suspension or emulsion, or to analyze them while separating. It has a wide range of applications and is suitable for use in laboratories such as chemical, food, pharmaceutical, environmental, mining, and teaching. Let's take a look at it~
Ohaus FrontierTM 5000Multi Pro Multi-Function Centrifuge 
Adhering to Ohaus's centuries-old design and manufacturing experience, the new generation of FRONTIERTM 5000 series centrifuges is presented. All desktop models are imported from Germany. The FrontierTM 5000Multi Pro Multi-Function Centrifuge is available with a choice of different rotors and adapters for centrifugation of a wide range of samples and can be individually configured for experimentation. The sample throughput is up to 6x250 ml, and it also has low microliter sample handling capacity. The function covers almost all common applications in the laboratory, such as routine laboratory centrifugation, inspection and industrial applications, and meets the stringent requirements of customers for quietness and safety. With excellent man-machine design, rich functional configuration and multiple safety guarantees, FRONTIERTM 5000 series centrifuges will be another reliable choice in your laboratory.
Features:
â— Powerful and flexible
The FrontierTM 5000 Multi Pro Multi-Function Centrifuge delivers medium-volume, high-speed centrifugation and is powerful, with a wide selection of rotors and adapters for centrifugal separation of all types of samples. 
â— Design friendly and easy to operate <br> Designed intuitively, the two-line backlight LCD can display all running information and parameter settings in real time; using the automatic rotor recognition system, it can be quickly switched between different applications. 
â— Imported <br> reliable and durable machine imported from Germany, a number of security and stability design verification to provide better protection for your experiment. 
â— Built-in protection security <br> Provides reliable security, built-in overspeed sensor, unbalanced sensor and self-diagnosis system to ensure safe operation of the centrifuge. 
Laboratory instruments, also known as the backbone of scientific research. A quality centrifuge is definitely a good helper for your lab. 
If you want to know more about the centrifuge series or Ohaus's other laboratory equipment, or are looking for more professional and detailed selection guide, please call 4008-217-188, or click to read the original text. And leave relevant information, our professional engineers will help you!