Common yoghurt fermentation production methods

 

Yogurt, fresh milk by yoghurt culture fermented dairy products. Yogurt fermentation agent is used in making yogurt specific microbial culture material . Fermenting agent in the production of yoghurt very important role in the process , fermentation agent is a yoghurt product acid production and production base of incense and the main reason. The quality of yogurt fermentation agent depends primarily on the quality of the type of yogurt and vitality.
Production methods
(Common yoghurt fermentation) liquid yogurt fermentation agent due to its quality of instability and vulnerability to pollution, large yogurt manufacturers have gradually been eliminated , only a few small factories are also yogurt together with some university or institute for production ; deep frozen yogurt fermentation agent because the cost of deep cold chain is relatively high , the use of extensive restrictions ; while DVS yoghurt culture in its price gradually accepted by domestic manufacturers , has begun in some large manufacturers to promote the use of yogurt .
In previous yogurt production process, the bacteria ferment yogurt yogurt manufacturers to set up a separate plant species , in order to complete the “pure breed bacteria → activation → expanded → intermediate → mother ferment ferment ferment → Work ” This a process , the process step more stringent technical requirements , manufacturers generally limited due to the production conditions , frequent quality problems. Therefore, the developed countries in the dairy , homemade yogurt manufacturer does not ferment , fermentation agent produced by specialized enterprises with yoghurt culture , fermented dairy products to meet the requirements of manufacturers . Hansen Danish central laboratory by the end of 1988 produce ultra concentrated DVS yoghurt culture .
DVS yoghurt culture (Directed Vat Set, DVS) is a series of highly concentrated and standardized freeze-dried starter culture bacteria, can be directly added to the heat treatment of raw milk to ferment , without its activation, spread cultivation other preprocessing . DVS yogurt starter number of viable cells is generally 1010 – 1012 CFU / g. Since DVS yoghurt culture of strong vitality , many types of yogurt manufacturers can be arbitrarily chosen , thus enriching the variety of yogurt products , while eliminating strain workshop , reducing staff , investment and space , simplifying the production processes. DVS yoghurt culture without expanding culture , can be used directly , easy to manage. DVS yoghurt culture production and application can ferment production specialization , socialization, standardization and unification , so that the yogurt production standardization , improve the quality of yogurt to protect the interests of consumers and health.

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Milk antibiotic detection reagents (antibiotics, milk, yoghurt) to the operating instructions

First, the detection principle
This reagent is microbial inhibition assay of antibiotics in milk content . In each well of the spores spread containing agar medium and a pH indicator . When incubated at 65 ° , the growth and development micropores spores , the growth of bacteria , the production of acid , thereby reducing the pH of the medium . the indicator of pH change from the original blue- purple to yellow-green .
If the added milk contains antibiotics, antibiotics will inhibit microbial growth , so as not to produce acid , the indicator will not change color . Reagent will keep the original blue- purple. Ultimately based on the color change can be determined whether milk samples containing antibiotics .
Second, the operation
1, to determine the number of samples to be tested , along with a knife cut open the gap between the strips and the metal film . Remove the corresponding number of micropores . Ready for experiments . Attention to prevent cut through the remaining metal film on the microplate .
2 , removed from the plastic frame to be detected on a microporous , in an empty plastic box. The remaining microplate must be immediately returned to the plastic bag ,4-8 ℃ under refrigerated.
3 , will be used on a porous metal film Peel off the adhesive , in each well was added 50μl milk samples . Recommend using automatic sampling trace guns spiked sample .
4, with the kit adhesive paper carefully sealed microplate ( strip ) , put it vertically to the already preheated to 65 ℃ in water bath or incubator in . Must ensure that the micropores have been completely sealed. If the cultivation process of penetration of water into the pores , will produce erroneous test results.
5 , incubation time reference reagent vessel lid on the standard time . In the experiments suggest we do negative and positive control samples . If the negative control samples , places the negative control samples turn yellow on the time .
6 , Peiyan complete, remove porous, microporous side from observation . Green – or yellow indicates that the sample does not contain antibiotics ( negative ) , and blue – purple for samples containing antibiotics ( positive ) . Green – blue antibiotic concentrations close to the detection limit of the kit , then redo the testing proposal
Third, pay attention
(1) We recommend the use of the negative control samples ( no anti-milk ) and positive control samples ( a higher concentration of antibiotics, such as 10mg / L penicillin -G’s milk ) to determine the best time required for heating the culture
(2) This kit is for antibiotics and other antimicrobial substances such as detergents and disinfectants extremely sensitive . Samples must be prevented from being contaminated by these substances .
(3) microplate should be sealed in a plastic bag to prevent the pores dry and refrigerated storage at 4-8 ℃
(4) small amounts of natural milk inhibitors do not affect the result of the assay reagent . However, colostrum , lactation period and the end of mastitis in milk will increase inhibitory substances , when test results will be affected. 5 If you want to analyze milk containing preservatives , incubation time must be extended a few minutes 6 . Correct interpretation depends on the results of the side holes .

More about:Milk antibiotic detection reagents (antibiotics, milk, yoghurt sales
From:Food bacteria