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E-mail
lei@guiyisci.com
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Phone
13651923355
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Address
Room 502, No. 25, Lane 1288, Luoning Road, Baoshan District, Shanghai
Shanghai Siyi Biochemical Technology Co., Ltd
lei@guiyisci.com
13651923355
Room 502, No. 25, Lane 1288, Luoning Road, Baoshan District, Shanghai
Q1
After diluting the soy protein isolate sample 10 times, it is still quite viscous. What should be done when taking the sample?
Without changing the principle of the test sample, different dilution factors can be selected.
Q2
Before testing fruit and vegetable juice, adjust the pH of the sample as needed. How to understand "as needed"?
It is commonly believed that if the pH value of the sample remains below 5 after dilution, it is still necessary to adjust the pH.
Q3
Do beverage samples produced using aseptic production processes (usually with low bacterial load) need to undergo 2 to 3 dilutions during factory testing? Can microorganisms be directly detected in the original solution?
Based on the degree of sample contamination, it can be directly detected using the original solution.
Q4
GB 19302-2025 "National Food Safety Standard Fermented Milk" Microbial Table: Pre treatment Dilution Method: Is it only for Escherichia coli? Is it for solid and semi-solid samples? Should liquid samples also be processed in this way? The new standard does not specify yeast restrictions. Can it be considered that the national standard does not require yeast for fermented milk?
It is aimed at the coliform bacteria group; The standard is for fermented milk, and the sample state is relatively viscous, so it should be processed according to the standard and the actual situation of the sample; The new standard for fermented dairy products does not require yeast testing and is controlled during the production process.
Q5
In the sample dilution standard requirements, 25g of the sample is weighed and placed in a sterile diluent containing 225mL. Can the sterile diluent be added directly after weighing the sample? Can diluent be weighed?
You can weigh the sample first, and then add 225mL of diluent, which can be weighed.
Q6
How to ensure aseptic operation during the process of peeling off nut products?
It can be broken with a small hammer through a sterile bag and sampled with sterile forceps.