菌落总数的检测方法（Method for detecting colony number）
The detection method of the total number of colonies of.Txt31 rock under the grass to teach us strong, cliff wild lily to teach us, mountain pine teach us hard rain, cold nitens teach us to meet the snow. The detection method of the total number of colonies.Txt if there is an afterlife, do a tree, stand eternal, no sad gesture. Half in the soil, quiet, half in the wind flying, half fall cool, half bathed in sunshine, very silent, very proud, never rely on never looking for. Method for detecting colony number
着重的读音
First, the total number of colonies introduced:
Colony is the growth of bacteria on solid medium, which can be recognized by the naked eye. It is a collection of tens of thousands of the same bacteria. When the sample is diluted to some extent and mixed with the culture medium, each bacterial cell capable of growing can form a visible colony on the plate under certain culture conditions.
英语励志语录
The total number of colonies refers to the total number of bacterial colonies grown under certain conditions (such as aerobic conditions, nutritional conditions, pH, culture temperature and time), per gram (per milliliter) of samples. According to the national standard method, namely in the aerobic condition, 37 degrees 48h culture, to the total number of bacterial colony growth in general on the nutri
ent agar plates, so anaerobic or microaerophilic bacteria, have special nutritional requirements and mesophilic bacteria, becau the existing conditions can not meet the physical needs, so it is difficult to reproduce. Therefore, the total number of colonies
does not mean that the total number of bacteria in practice, the total number of colonies and bacteria can not distinguish between species, so sometimes referred to as the number of bacteria, aerobic bacteria and so on.
The determination of total bacterial count is ud to determine the extent of food contamination by bacteria and the quality of hygiene. It reflects whether food meets the hygienic requirements in the process of production so as to make a proper hygienic evaluation of the samples being taken. The total number of colonies indicates the quality of food hygiene to a certain extent.
Two, inspection methods
Determination of the total number of colonies, generally will be 10 times the sample made of veral different increasing dilution, then from each dilution were removed and 1mL bad mixed nutrient agar in sterilized Petri dish liquid, at a certain temperature, training after a certain period of time (usually 48 hours), the number of records formed in each Petri dish on the basis of the colony, dilutio
n was calculated per gram (or ml) bacteria contained in the original sample number.
Basic operations include dilution of samples - pouring into dishes - - culture for 48 hours - counting reports.
语言的本质The total number of domestic and foreign colony determination methods are basically the same, from the sample processing, dilution, pour plate count to report what was different, but in some specific requirements slightly, as some countries in
the sample dilution and pour into the culture of Straw, the flow of liquid in dilute solution, the oscillation amplitude, time and the number and placement time are made more specific provisions.房地产估价规范>警惕的反义词
Inspection method:
双重人格的表现GB4789.2-94 People's Republic of China national standard microbiological examination of food hygiene. Determination of colony count
SN0168-92 "People's Republic of China import and export commodity inspection standard", "export food bacterial count"
Three, description
(1) sample handling and dilution:
1. operation methods: aptic operation from the sample 25g (or 25ml), sterilized glass bottles put in 225mL sterilized saline or other diluent (in bottle pret in the appropriate number of glass beads) or sterilized mortar, after full vibration or grinding uniform dilution 1:10.五个字谜
After adding diluent, the solid sample should be sterilized and treated with 8000~10000r/min at the speed of 1min to make a uniform dilution of 1:10.
1ml sterilization tube was ud to absorb the 1:10 diluted liquid 1ml, and then slowly injected along the tube wall into a test tube containing 9ml sterilized physiological saline or
other diluent. The shaking tube was mixed evenly to make 1:100 dilution.
Another 1ml sterilization straw, according to the order of operation in order to increa the dilution of 10 times, so that every increa in dilution once, then replaced with 1 1ml sterilization straw.
2. aptic operation: the operation must have the concept of "aptic operation", the glassware must be completely sterilized, and no bacteria or antibacterial substances remain. The scissors, tweezers and other instruments must also be sterilized. If the sample is packed, apply the 75% ethanol to the
packing opening and then sample it.
The operation should be performed in an over clean table or in a sterilized apsis room. Agar plates were expod at the table for 15 minutes, and each panel must not exceed 15 colonies.
3. reprentative sampling: in the ca of solid samples, sampling should not focus on one point, should be ud in veral parts. The solid sample must be homogenized or ground, and the liquid sample must be shaken to obtain a uniform dilution.
Four
Sample dilution error: in order to reduce the dilution error of the sample, every diluted liquid should be shaken sufficiently to make it uniform at the successive dilution, and a straw should be replaced at each dilution.
In continuous dilution, the liquid in the pipette shall be carried along the wall of the pipe, and the tip of the pipette shall not be inrted into the diluent so as not to dissolve the liquid which is externally adhered to the pipette.
In order to reduce dilution error, SN standard was ud to take 10mL dilution into 90mL buffer.
5. diluent: sample dilution is mainly sterilized physiological saline, and some u phosphate buffer (or 0.1% peptone water), the latter has a certain protective effect on the bacterial cells that have been damaged by food. If the food containing higher salt (such as soy sauce) is diluted, sterilized distilled water can be ud.
(two) pour into cultivation;
桔黄1. methods of operation: or to pollution are estimated according to the standard requirements, choo a suitable 2~3 dilution, dilution and increasing for 10 times respectively, to draw the Straw dilution removed 1ml dilution in sterile Petri dish, each dilution two Petri dishes.
Bring the nutrient agar medium of cool to 46 DEG into a pan, about 15ml, and turn into a pan and mix evenly. At the same time, the nutrient agar medium was poured into the sterilized dish with 1ml dilution (without sample) as blank control.
When the agar is solidified, the plate is turned over and placed at 36 + 1 DEG C; the incubator is cultured for 48 + 2H; the number
