阅读说明：本技术 一种冷水凝胶及其应用 (Cold hydrogel and application thereof ) 是由 张伟 刘莎 王子铭 魏兴峰 黄启钊 于 2020-12-25 设计创作，主要内容包括：本发明提供了一种冷水凝胶及其应用,所述冷水凝胶包括黄原胶、瓜尔胶和聚丙烯酸钠,所述黄原胶、瓜尔胶和聚丙烯酸钠的质量比为(1～2):(1～2):1。本发明还提供了一种微生物检测培养基,所述微生物检测培养基包括所述的冷水凝胶。本发明通过对黄原胶、瓜尔胶和聚丙烯酸钠进行合理的配比,制备得到的冷水凝胶具有极好的吸水性、保水性和凝胶速度；所述微生物检测培养基的透明度更好,凝胶强度高,便于菌落的观察、计数及挑取。将所述微生物检测培养基粉末通过不干胶固定在培养皿内底壁,制成的微生物检测试剂盒使用方便,可应用于好氧菌及兼性厌氧菌的检测中,制备方法简单高效,应用价值极高。(The invention provides a cold water gel and application thereof, wherein the cold water gel comprises xanthan gum, guar gum and sodium polyacrylate, and the mass ratio of the xanthan gum to the guar gum to the sodium polyacrylate is (1-2): 1. The invention also provides a microorganism detection culture medium which comprises the cold hydrogel. According to the invention, the xanthan gum, the guar gum and the sodium polyacrylate are reasonably proportioned, so that the prepared cold water gel has excellent water absorption, water retention and gel speed; the microorganism detection culture medium has better transparency and high gel strength, and facilitates observation, counting and picking of bacterial colonies. The microorganism detection culture medium powder is fixed on the inner bottom wall of the culture dish through the adhesive sticker, the prepared microorganism detection kit is convenient to use, can be applied to detection of aerobic bacteria and facultative anaerobic bacteria, and is simple and efficient in preparation method and high in application value.)

1. The cold water gel is characterized by comprising xanthan gum, guar gum and sodium polyacrylate, wherein the mass ratio of the xanthan gum to the guar gum to the sodium polyacrylate is (1-2): 1.

2. The cold water gel of claim 1, wherein the mass ratio of xanthan gum, guar gum and sodium polyacrylate is 3:3: 2.

3. A microbiological detection media comprising the cold hydrogel of claim 1 or 2 and other components.

4. The microorganism detection medium according to claim 3, wherein the mass ratio of the cold hydrogel to the other components is (1-3: 1, preferably 2: 1;

preferably, the other components include nutrients and a microbial detection indicator;

preferably, the nutritional ingredients include tryptone, yeast extract and glucose;

preferably, the microorganism detection indicator comprises TTC;

preferably, the other components comprise 4-6 parts of tryptone, 2-3 parts of yeast extract powder, 0.5-1 part of glucose and 0.02-0.06 part of TTC in parts by weight;

preferably, the other components include 5 parts by weight of tryptone, 2.5 parts by weight of yeast extract, 1 part by weight of glucose and 0.05 part by weight of TTC.

5. A method for preparing the microorganism detection medium according to claim 3 or 4, wherein the method comprises:

mixing the cold hydrogel of claim 1 or 2 with other components to provide the microbiological detection media;

preferably, the preparation method comprises: mixing xanthan gum, guar gum and sodium polyacrylate in a mass ratio of (1-2): 1 to prepare cold hydrogel, and mixing the cold hydrogel with other components in a mass ratio of (1-3): 1 to obtain the microbial detection culture medium.

6. A microorganism detection kit, comprising the microorganism detection medium according to claim 3 or 4 fixed to the inner bottom wall of a sealed petri dish;

preferably, the sealed culture dish is a round sealed plastic culture dish;

preferably, the diameter of the circular sealed plastic culture dish is 40-100 mm, and preferably 50 mm.

7. A method for preparing the microorganism detection kit according to claim 6, wherein the method comprises: fixing a microorganism detection culture medium on the inner bottom wall of a culture dish, sealing, and sterilizing to obtain the microorganism detection kit;

preferably, the method of sterilization comprises microwave sterilization;

preferably, the microwave sterilization time is 2-5 min, preferably 3 min.

8. The preparation method according to claim 7, wherein the microorganism detection culture medium is fixed on the inner bottom wall of the culture dish by a non-setting adhesive;

preferably, the operation method for fixing the adhesive sticker comprises the following steps: coating the non-setting adhesive on the inner bottom wall of the culture dish, and spraying the microorganism detection culture medium on the non-setting adhesive to complete the fixation of the microorganism detection culture medium;

preferably, the spraying is performed by a nebulizer.

9. The method according to claim 7 or 8, comprising in particular the steps of:

(1) mixing xanthan gum, guar gum and sodium polyacrylate in a mass ratio of (1-2): 1 to prepare cold hydrogel, and mixing the cold hydrogel with other components in a mass ratio of (1-3): 1, wherein the other components comprise 4-6 parts of tryptone, 2-3 parts of yeast extract powder, 0.5-1 part of glucose and 0.02-0.06 part of TTC to obtain a microorganism detection culture medium;

(2) coating adhesive sticker on the inner bottom wall of a round plastic culture dish, spraying the microorganism detection culture medium on the adhesive sticker through a sprayer, and then sealing the round plastic culture dish to obtain a round sealed plastic culture dish;

(3) and (3) performing microwave sterilization on the round sealed plastic culture dish obtained in the step (2) for 2-5 min, and performing aseptic packaging to obtain the microbial detection kit.

10. Use of a cold water gel according to claim 1 or 2, a microbial detection medium according to claim 3 or 4 or a microbial detection kit according to claim 6 for microbial detection.

Technical Field

The invention belongs to the technical field of microbial detection, and particularly relates to a cold hydrogel and application thereof.

Background

The food microorganism detection is a basic work of food safety inspection and is a basis for ensuring food safety. At present, the traditional microbial detection method comprises a morphological detection method and a biochemical detection method, which are common food microbial detection technologies and have high detection precision, but the detection process is complex in operation, needs more manpower and material resources and is time-consuming.

With the continuous progress of science and technology, novel detection methods and detection kits are continuously available. CN1876829A discloses a kit for anti-interference rapid detection of microbial numbers by using an ATP bioluminescence method, which comprises making an ATP standard curve in a selected bioluminescence instrument and a selected system, obtaining a linear regression equation after logarithm is obtained, carrying out ATP bioluminescence detection on a sample liquid subjected to non-target ATP removal and microbial ATP extraction in the same instrument and system by using the same batch of enzyme, simultaneously making a blank control to obtain a sample and a blank CPM or RLU value, obtaining the ATP concentration of the sample through the established regression equation after logarithm is obtained on the blank removed net relative luminous value, and converting the ATP concentration into the cell number of bacteria, yeasts, mold hoops or single cells according to the ATP content of the microorganisms such as the bacteria, the yeasts, the molds, the single-cell microalgae and the like. The method has the advantages of rapid detection, small error, complex operation, certain theoretical knowledge base, high requirement on the technical level of related workers and unsuitability for practical production detection.

CN211284374U discloses food microorganism short-term test device, including food microorganism short-term test device body, food microorganism short-term test device body includes food microorganism short-term test appearance, probe and disinfection box, the disinfection box bonds in food microorganism short-term test appearance's bottom, the probe sets up the one side at food microorganism short-term test appearance, the bottom of probe is provided with the probe, the bottom cover of probe is equipped with the sleeve pipe, sheathed tube bottom bonds and has the cardboard, one side of disinfection box bonds and has the disinfection pipe, the opposite side of disinfection box bonds and has the clearance pipe, the top of disinfection box bonds and has the storing box, open and shut switch one, switch two and switch three on the food microorganism short-term test appearance through the bolt, the inboard bonding of disinfection pipe has the heating wire. The food microorganism rapid detector has the advantages of reasonable design, convenient use and short time consumption, but needs to be assisted by a corresponding detection instrument, can not be applied to field detection, and has poor applicability.

At present, the detection of food microorganisms generally has the restrictive factors of complex operation, long time consumption or need of professional instruments and the like. How to provide a method for detecting microorganisms, which can make the detection method simpler and easier, has lower operation difficulty, and does not need to use complex detection instruments, has become a problem to be solved urgently.

Disclosure of Invention

Aiming at the defects and actual requirements of the prior art, the invention provides a cold hydrogel and an application thereof, wherein the cold hydrogel has the advantages of good water retention, high gel strength, high gel speed and the like, is mixed with culture medium powder and is fixed on the inner bottom wall of a culture dish through adhesive sticker, and the prepared microorganism detection kit has the advantages of simplicity and convenience in use, easiness in storage and the like, is matched with a biological indicator, so that grown bacterial colonies are easily distinguished and picked, can be simultaneously applied to detection of aerobic bacteria and facultative anaerobic bacteria, and has extremely wide application value.

In order to achieve the purpose, the invention adopts the following technical scheme:

in a first aspect, the invention provides a cold water gel, which includes xanthan gum, guar gum and sodium polyacrylate, wherein the mass ratio of the xanthan gum to the guar gum to the sodium polyacrylate is (1-2): 1, and may be, for example, 1:1:1, 1:1.5:1, 1:2:1, 1.5:1:1, 1.5:1.5:1, 1.5:2:1, 2:1:1, 2:1.5:1 or 2:2: 1.

According to the invention, the xanthan gum with the molecular weight of 450 ten thousand daltons is selected, the xanthan gum has high diffusion speed, can be dissolved in cold water, has high stability, can be kept stable in an acid environment and a large temperature range, and also has the characteristics of enzymolysis resistance, high salt resistance and shear resistance, the xanthan gum has extremely high hydrophilic capacity, and the water absorption of internal substances can be influenced by the water absorption expansion of the outer layer xanthan gum to form micelles if water is not added for stirring; the guar gum with the molecular weight of about 22 ten thousand daltons is selected as the hydrophilic colloid, the guar gum can enhance the hardness of the gel, the gelling speed is high, the water solubility is good, but the water absorption rate is slightly poor; the invention selects the sodium polyacrylate with the molecular weight of about 350 ten thousand daltons, which has good thickening property and can enhance the hardness of the gel, but the water absorption is slightly poor, and the stability of the gel is also poor; according to the invention, the xanthan gum, the guar gum and the sodium polyacrylate are compounded, so that the prepared cold hydrogel has good water absorption rate and water retention rate, high gelling speed and good stability, and the water absorption rate, the water retention rate, the diffusion range, the gelling speed and the gelling stability of the mixed gel are optimal and the application value is extremely high through reasonable proportioning of the raw materials.

Preferably, the mass ratio of the xanthan gum to the guar gum to the sodium polyacrylate is 3:3: 2.

In a second aspect, the present invention provides a microbiological detection media comprising the cold hydrogel of the first aspect and other components.

The cold water gel has the advantages of good water retention, high gel strength, high gel speed, transparent texture, no toxicity, no harm and good stability, can not be decomposed and utilized by bacteria, can not damage the structure due to hypha growth, can keep a solid state in the temperature range of microbial growth, meets the requirements of a microbial detection culture medium on transparency, stable structure, high recovery rate and easy fungus picking, is a good microbial culture medium coagulant, has higher transparency, better water retention effect, better gel capability and better stability compared with the traditional culture medium coagulant agar, overcomes the defect that the dosage needs to be adjusted due to factors such as seasonal change, the quality problem of the agar and the like, and needs to be dissolved under heating conditions when the agar is used as the culture medium coagulant, when the cold water gel is cooled to 40-50 ℃, the cold water gel is solidified into a solid, and if the resistant ingredients or the nutritional ingredients are added too early, the resistance ingredients or the nutritional ingredients can be inactivated due to too high temperature.

Preferably, the mass ratio of the cold water gel to other components is (1-3: 1), and for example, the mass ratio can be 1:1, 1.5:1, 2:1, 2.5:1 or 3:1, and is preferably 2:1.

Preferably, the other components include nutrients and a microbial detection indicator.

Preferably, the nutritional ingredients include tryptone, yeast extract and glucose.

Preferably, the microbial detection indicator comprises TTC.

In the invention, the TTC is also called 2,3, 5-triphenyltetrazolium chloride and is a colorless substance, and microorganisms can generate a large amount of reducing hydrogen during respiration and can reduce the reducing hydrogen into red triphenylformazan (TTF), so that bacterial colonies are red, and counting and picking of researchers are more convenient.

Preferably, the tryptone is present in the other components in an amount of 4 to 6 parts by weight, for example 4 parts, 4.1 parts, 4.2 parts, 4.3 parts, 4.4 parts, 4.5 parts, 4.6 parts, 4.7 parts, 4.8 parts, 4.9 parts, 5 parts, 5.1 parts, 5.2 parts, 5.3 parts, 5.4 parts, 5.5 parts, 5.6 parts, 5.7 parts, 5.8 parts, 5.9 parts or 6 parts.

Preferably, the yeast extract powder is 2 to 3 parts by weight of the other components, for example, 2 parts, 2.1 parts, 2.2 parts, 2.3 parts, 2.4 parts, 2.5 parts, 2.6 parts, 2.7 parts, 2.8 parts, 2.9 parts or 3 parts.

Preferably, the glucose is present in the other components in an amount of 0.5 to 1 part by weight, for example 0.5, 0.6, 0.7, 0.8, 0.9 or 1 part by weight.

Preferably, the weight part of the TTC in the other components is 0.02-0.06 parts, and may be 0.02 parts, 0.03 parts, 0.04 parts, 0.05 parts or 0.06 parts, for example.

Preferably, the other components comprise, by weight, 4-6 parts of tryptone, 2-3 parts of yeast extract powder, 0.5-1 part of glucose and 0.02-0.06 part of TTC.

Preferably, the other components include 5 parts by weight of tryptone, 2.5 parts by weight of yeast extract, 1 part by weight of glucose and 0.05 part by weight of TTC.

In a third aspect, the present invention provides a method for preparing the microorganism detection medium according to the second aspect, the method comprising:

mixing the cold water gel of the first aspect with other components to obtain the microbial detection medium.

According to the invention, the cold hydrogel is mixed with other components, the prepared microorganism detection culture medium is a powdery substance, can be solidified after being mixed with the diluent of the sample to be detected, and is subjected to subsequent culture and detection experiments.

Preferably, the preparation method comprises: mixing xanthan gum, guar gum and sodium polyacrylate in a mass ratio of (1-2): 1 to prepare cold hydrogel, and mixing the cold hydrogel with other components in a mass ratio of (1-3): 1 to obtain the microbial detection culture medium.

In a fourth aspect, the present invention provides a microorganism detection kit comprising the microorganism detection medium of the third aspect fixed to the inner bottom wall of a sealed culture dish.

In the invention, the microorganism detection culture medium contains tryptone, yeast extract powder and glucose, so that the requirements of the microorganism on a carbon source, a nitrogen source, inorganic salt and a growth factor in the growth process are met, the excellent water retention performance of the cold hydrogel provides sufficient water for the growth of the microorganism, and the requirements of the microorganism growth on the basic components of the culture medium are met; by adding TTC, the grown bacterial colony is red and clearer, and the work of researchers is facilitated; the microorganism detection kit is convenient to use, only needs to uniformly mix diluent containing a sample to be detected with powder on the inner bottom wall of a culture dish, then cultures the diluent, and can be applied to detection of aerobic bacteria and facultative anaerobic bacteria; the kit is filled with culture medium powder, so that the storage and the transportation are easier, and the service life is prolonged; the culture medium powder is fixed on the inner bottom wall of the culture dish through the adhesive sticker, so that the movement of the powder in the transportation process can be reduced, and the stability of the product in the transportation process is improved.

Preferably, the sealed culture dish is a circular sealed plastic culture dish.

Preferably, the diameter of the circular sealed plastic culture dish is 40-100 mm, for example, 40mm, 50mm, 60mm, 70mm, 80mm, 90mm or 100mm, preferably 50 mm.

In a fifth aspect, the present invention provides a method for preparing the microorganism detection kit of the fourth aspect, wherein the method for preparing the microorganism detection kit comprises: and (3) fixing the microorganism detection culture medium on the inner bottom wall of the culture dish, sealing, and sterilizing to obtain the microorganism detection kit.

According to the invention, the culture medium powder is fixed on the inner bottom wall of the culture dish, so that the movement of the powder in the transportation process is reduced, and the stability and the sanitation of the kit are improved; subsequently, the culture dish is sealed and sterilized again, so that the culture dish and the microorganism detection culture medium in the culture dish are always in a sterile state, convenience is brought to researchers to use at any time, and the condition that false positive results are generated due to mixed bacteria pollution in the transportation or storage process can be avoided.

Preferably, the method of sterilization comprises microwave sterilization.

Preferably, the microwave sterilization time is 2-5 min, for example, 2min, 2.5min, 3min, 3.5min, 4min, 4.5min or 5min, preferably 3 min.

Preferably, the microorganism detection culture medium is fixed on the inner bottom wall of the culture dish through adhesive sticker.

Preferably, the operation method for fixing the adhesive sticker comprises the following steps: and (3) coating the self-adhesive on the inner bottom wall of the culture dish, and spraying the microorganism detection culture medium on the self-adhesive to complete the fixation of the microorganism detection culture medium.

Preferably, the spraying is performed by a nebulizer.

As a preferred technical scheme, the preparation method of the microbial detection kit specifically comprises the following steps:

(1) mixing xanthan gum, guar gum and sodium polyacrylate in a mass ratio of (1-2): 1 to prepare cold hydrogel, and mixing the cold hydrogel with other components in a mass ratio of (1-3): 1, wherein the other components comprise 4-6 parts of tryptone, 2-3 parts of yeast extract powder, 0.5-1 part of glucose and 0.02-0.06 part of TTC to obtain a microorganism detection culture medium;

(2) coating adhesive sticker on the inner bottom wall of a round plastic culture dish, spraying the microorganism detection culture medium on the adhesive sticker through a sprayer, and then sealing the round plastic culture dish to obtain a round sealed plastic culture dish;

(3) and (3) performing microwave sterilization on the round sealed plastic culture dish obtained in the step (2) for 2-5 min, and performing aseptic packaging to obtain the microbial detection kit.

In a sixth aspect, the invention provides a cold water gel according to the first aspect, a microorganism detection medium according to the second aspect and a microorganism detection kit according to the fourth aspect for use in microorganism detection.

According to the invention, the prepared cold water gel has good water absorption, water retention, permeability and gel stability by reasonably proportioning xanthan gum, guar gum and sodium polyacrylate; after being mixed with other components, the prepared microbial detection culture medium is rich in nutrition and stable in structure, and the grown bacterial colony is red and more obvious by adding TTC, so that the culture medium can be used for related work of microbial detection; the microbial detection medium powder is fixed on the inner bottom wall of a sealed culture dish, and a microbial detection kit prepared after sterilization can be solidified into gel at room temperature, is convenient to use, can detect aerobic bacteria and facultative anaerobic bacteria, and has an extremely wide application range.

Compared with the prior art, the invention has the following beneficial effects:

(1) according to the invention, through reasonable proportioning of xanthan gum, guar gum and sodium polyacrylate, the obtained cold hydrogel has excellent water absorbability and water retention, the water retention rate is not lower than 78.64%, the water absorption rate is not lower than 38.73g/g, the diffusion speed is not higher than 39s, the gelling speed is extremely high, the stability of the gel is excellent, the texture is uniform and transparent, the fluidity is weak, and the cold hydrogel has wide application in the aspect of microorganism detection;

(2) according to the invention, the cold water gel and other components are reasonably proportioned, the prepared microorganism detection culture medium has excellent water retention, gel speed and stability, and compared with the traditional agar, the microorganism detection culture medium is not influenced by environmental factors such as seasons and the like, has better transparency and is more convenient to use, and the bacterial colony grown by adding TTC as a biological indicator is red and more obvious, so that the microorganism detection culture medium is convenient for the work of related personnel;

(3) according to the invention, the microorganism detection culture medium powder is fixed on the inner bottom wall of the culture dish through the adhesive sticker, so that the service life of the kit is prolonged, and the stability of the product in the transportation and storage processes is improved; the microorganism detection kit is convenient to use, only needs to add diluent containing a sample to be detected into a culture dish to be mixed with the culture medium powder, and then culture is carried out, so that a complex operation technology is not needed, and the requirement on detection personnel is low; the kit has good comprehensive performance, the growth state of colonies is 5 minutes, and the number of the colonies is not less than 177; the difficulty degree of picking is 4 points; the grown bacterial colony is red, and the difficulty degree of observation is 4 points; the pouring method can be simultaneously applied to the detection of aerobic bacteria and facultative anaerobic bacteria, and overcomes the technical defect that the flat plate detection method in the prior art is only suitable for the relevant detection of the aerobic bacteria;

(4) the preparation method of the microbial detection kit is simple and efficient, does not need complex production instruments, can ensure that the interior of the microbial detection kit is always maintained in a sterile state by a mode of sealing and then sterilizing, is convenient to detect, avoids the occurrence of false positive conditions such as mixed bacteria pollution and the like, and has extremely high application value.

Detailed Description

To further illustrate the technical means and effects of the present invention, the present invention is further described with reference to the following examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention.

The examples do not show the specific techniques or conditions, according to the technical or conditions described in the literature in the field, or according to the product specifications. The reagents or apparatus used are conventional products commercially available from normal sources, not indicated by the manufacturer.

Raw materials:

xanthan gum is purchased from Shenzhen Baoyau science and technology company;

guar gum is purchased from Shenzhen BaoYe science and technology company;

polyacrylamide was purchased from hong cheng yuan biotechnology;

tryptone was purchased from Guangdong Huanji Microbiol technologies, Inc.;

the yeast extract powder is obtained from Kyork, Guangdong, Microbiol technologies, Inc.;

glucose was purchased from Beijing Omboxing Biotechnology, Inc.;

TTC was purchased from bio-technologies ltd, obozosin, beijing;

the culture dish is purchased from a pregaba experimental article;

coli was purchased from ATCC with strain number ATCC 25922.

Example 1

This example provides a cold water gel comprising, by weight, 1.5 parts xanthan gum, 1.5 parts guar gum, and 1 part sodium polyacrylate.

Example 2

This example provides a cold water gel, which includes, by weight, 1 part of xanthan gum, 1 part of guar gum, and 1 part of sodium polyacrylate.

Example 3

This example provides a cold water gel, which includes, by weight, 1 part of xanthan gum, 2 parts of guar gum, and 1 part of sodium polyacrylate.

Example 4

This example provides a cold water gel, which includes, by weight, 2 parts of xanthan gum, 1 part of guar gum, and 1 part of sodium polyacrylate.

Example 5

This example provides a cold water gel, which includes, by weight, 2 parts of xanthan gum, 2 parts of guar gum, and 1 part of sodium polyacrylate.

Comparative example 1

The only difference from example 1 is that in this comparative example no xanthan gum was added and the missing parts by weight were supplemented with 0.9 parts guar and 0.6 parts sodium polyacrylate.

Comparative example 2

The only difference from example 1 is that in this comparative example no guar was added and the missing parts by weight were supplemented with 0.9 parts xanthan gum and 0.6 parts sodium polyacrylate.

Comparative example 3

The only difference from example 1 is that in this comparative example no sodium polyacrylate is added and the missing parts by weight are supplemented with 0.5 parts xanthan gum and 0.5 parts guar gum.

Comparative example 4

The comparative example provides a cold water gel comprising, by weight, 3 parts of xanthan gum, 3 parts of guar gum, and 1 part of sodium polyacrylate.

Comparative example 5

The only difference from example 1 is that in this comparative example, the xanthan gum was replaced by carrageenan and the remaining raw materials were the same as in example 1.

Comparative example 6

This comparative example provides a gel comprising, in parts by weight, 4 parts of agar.

Water retention detection

Weighing 0.10g of dry cold hydrogel powder, adding into a glass plate (D is 9cm) containing 5.0g of deionized water, mixing, swelling, weighing, and recording as m₁. Placing into a constant temperature incubator at 37 ℃, weighing after 12h, and recording the mass m_n. The water retention was calculated according to the following formula:

water retention rate [ < 1- (m) ]₁-m_n)/5]×100％。

Water absorption detection

Weighing 0.10g of dry cold hydrogel powder, adding 30g of deionized water, and fully absorbing for 3 min; draining by using a 100-mesh sieve, weighing the drained water, carrying out three-time parallel averaging on each group of samples, and calculating the water absorption rate according to the following formula:

water absorption (total liquid added-amount of liquid filtered out)/weight of cold hydrogel.

Diffusion rate and gel Effect detection

Uniformly adhering cold hydrogel powder to a transparent adhesive tape, and removing the cold hydrogel powder which cannot be adhered; adding 1mL of deionized water into the center of the adhesive tape, observing whether the deionized water can diffuse in the cold hydrogel powder, recording the time required for the diffusion to be finished, and observing whether gel is formed after water absorption and the transparency of the formed gel.

The results of testing the water retention, water absorption, diffusion rate and gelling effect of the gels of examples 1 to 5 and comparative examples 1 to 6 of the present invention after 12 hours are shown in table 1.

TABLE 1

The following can be seen from table 1:

(1) the cold water gel prepared in the embodiments 1 to 5 has excellent comprehensive performance, the water retention rate is not lower than 78.64%, the water absorption rate is not lower than 38.73g/g, the diffusion speed is not higher than 39s, the gelling speed is high, the fluidity is weak, and the gel is more transparent;

(2) compared with examples 1-5, the cold water gels prepared in comparative examples 1-5 have poor performance in some aspects, and compared with comparative example 1, the water retention rate, the water absorption rate and the diffusion speed of the cold water gel are poor and the cold water gel cannot form gel because xanthan gum is not added; comparative example 2, in which guar gum was not added, the diffusion rate was significantly slowed; comparative example 3, in which no sodium polyacrylate was added, the gel speed was slow and the texture of the gel was not uniform, with distinct particles present; in comparative example 5, carrageenan is used to replace xanthan gum, the water retention rate, water absorption rate and diffusion rate of the gel are poor, and the fluidity of the gel is strong; in the comparative example 4, the mass ratio of the xanthan gum to the guar gum to the sodium polyacrylate is not in the optimal range, and the water retention rate is influenced to a certain extent; the results show that only when the xanthan gum, the guar gum and the sodium polyacrylate are simultaneously contained and the mass ratio of the xanthan gum, the guar gum and the sodium polyacrylate is in the range of (1-2): 1, the cold hydrogel has good comprehensive performance, good water retention and water absorption capacity, high diffusion speed, uniform and transparent texture and stability;

(3) in the comparative example 6, agar is used as a raw material, the water retention rate is poor, and the agar cannot be gelatinized by directly adding deionized water, in the prior art, the agar can be dissolved under the condition of high-temperature heating, and can be gelatinized after being cooled, the use method is complicated, the cold hydrogel in the examples 1-5 can be gelatinized by only adding deionized water and mixing, the gelatinization speed is high, the use is convenient, and the application value is higher.

Application example 1

The application example provides a microorganism detection kit, and the preparation raw materials of the microorganism detection kit comprise, by weight, 17.1 parts of cold hydrogel (namely 6.4 parts of xanthan gum, 6.4 parts of guar gum and 4.3 parts of sodium polyacrylate) in example 1, 5 parts of tryptone, 2.5 parts of yeast extract powder, 1 part of glucose and 0.05 part of TTC.

The preparation method of the microbial detection kit comprises the following steps:

(1) mixing xanthan gum, guar gum and sodium polyacrylate according to a mass ratio to prepare cold water gel, and mixing the cold water gel with other components according to a mass ratio of 2:1, wherein the other components comprise 5 parts of tryptone, 2.5 parts of yeast extract powder, 1 part of glucose and 0.05 part of TTC to obtain a microorganism detection culture medium;

(2) coating adhesive sticker on the inner bottom wall of a circular plastic culture dish with the diameter of 50mm, spraying the microorganism detection culture medium on the adhesive sticker through a sprayer, and then sealing the circular plastic culture dish to obtain a circular sealed plastic culture dish;

(3) and (3) performing microwave sterilization on the round sealed plastic culture dish obtained in the step (2) for 3min, and performing aseptic packaging to obtain the microbial detection kit.

Application example 2

The application example provides a microorganism detection kit, and the preparation raw materials of the microorganism detection kit comprise, by weight, 9.6 parts of cold hydrogel (namely 3.2 parts of xanthan gum, 3.2 parts of guar gum and 3.2 parts of sodium polyacrylate), 6 parts of tryptone, 3 parts of yeast extract powder, 0.5 part of glucose and 0.06 part of TTC in example 2.

The preparation method of the microbial detection kit comprises the following steps:

(1) mixing xanthan gum, guar gum and sodium polyacrylate according to a mass ratio to prepare cold hydrogel, and mixing the cold hydrogel with other components according to a mass ratio of 1:1, wherein the other components comprise 6 parts of tryptone, 3 parts of yeast extract powder, 0.5 part of glucose and 0.06 part of TTC to obtain a microorganism detection culture medium;

(2) coating self-adhesive on the inner bottom wall of a circular plastic culture dish with the diameter of 40mm, spraying the microorganism detection culture medium onto the self-adhesive through a sprayer, and then sealing the circular plastic culture dish to obtain a circular sealed plastic culture dish;

(3) and (3) performing microwave sterilization on the round sealed plastic culture dish obtained in the step (2) for 2min, and performing aseptic packaging to obtain the microbial detection kit.

Application example 3

The application example provides a microorganism detection kit, and the preparation raw materials of the microorganism detection kit comprise, by weight, 21 parts of cold hydrogel (namely 5.25 parts of xanthan gum, 10.5 parts of guar gum and 5.25 parts of sodium polyacrylate), 4 parts of tryptone, 2 parts of yeast extract powder, 0.98 part of glucose and 0.02 part of TTC in example 3.

The preparation method of the microbial detection kit comprises the following steps:

(1) mixing xanthan gum, guar gum and sodium polyacrylate according to a mass ratio to prepare cold water gel, and mixing the cold water gel with other components according to a mass ratio of 3:1, wherein the other components comprise 4 parts of tryptone, 2 parts of yeast extract powder, 0.98 part of glucose and 0.02 part of TTC to obtain a microorganism detection culture medium;

(2) coating adhesive sticker on the inner bottom wall of a circular plastic culture dish with the diameter of 100mm, spraying the microorganism detection culture medium on the adhesive sticker through a sprayer, and then sealing the circular plastic culture dish to obtain a circular sealed plastic culture dish;

(3) and (3) performing microwave sterilization on the round sealed plastic culture dish obtained in the step (2) for 5min, and performing aseptic packaging to obtain the microbial detection kit.

Application example 4

The difference from application example 1 is only that the mass ratio of the cold hydrogel to other components in the application example is 4:1, that is, the raw materials for preparing the microorganism detection kit comprise 34.2 parts of the cold hydrogel (namely 12.8 parts of xanthan gum, 12.8 parts of guar gum and 8.6 parts of sodium polyacrylate) described in example 1, 5 parts of tryptone, 2.5 parts of yeast extract powder, 1 part of glucose and 0.05 part of TTC, and the rest raw materials and the preparation method are the same as those in application example 1.

Application example 5

The difference from application example 1 is only that the mass ratio of the cold hydrogel to other components in the application example is 1:2, that is, the raw materials for preparing the microorganism detection kit comprise 4.3 parts of the cold hydrogel described in example 1 (i.e. 1.6 parts of xanthan gum, 1.6 parts of guar gum and 1.1 parts of sodium polyacrylate), 5 parts of tryptone, 2.5 parts of yeast extract powder, 1 part of glucose and 0.05 part of TTC, and the rest raw materials and the preparation method are the same as those in application example 1.

Application example 6

The difference from the application example 1 is that TTC is not added in the application example, 0.03 part of tryptone and 0.02 part of yeast extract powder are supplemented in the lacking parts by weight, and the rest raw materials and the preparation method are the same as the application example 1.

Application example 7

The difference from the application example 1 is that the application example does not include a step of coating the non-setting adhesive, and the rest of the raw materials and the preparation method are the same as the application example 1.

Comparative application example 1

The difference from application example 1 is only that 17.1 parts of the cold water gel in comparative example 1 (i.e. 10.3 parts of guar gum and 6.8 parts of sodium polyacrylate) is used in the comparative application example instead of 17.1 parts of the cold water gel in example 1, and the rest of the raw materials and the preparation method are the same as in application example 1.

Comparative application example 2

The difference from application example 1 is only that 17.1 parts of the cold hydrogel in comparative example 2 (i.e., 10.3 parts of xanthan gum and 6.8 parts of sodium polyacrylate) is used in this comparative application example instead of 17.1 parts of the cold hydrogel in example 1, and the rest of the raw materials and the preparation method are the same as in application example 1.

Comparative application example 3

The difference from application example 1 is only that 17.1 parts of the cold water gel in comparative example 3 (i.e., 8.55 parts of xanthan gum and 8.55 parts of guar gum) is used in this comparative application example instead of 17.1 parts of the cold water gel in example 1, and the rest of the raw materials and preparation method are the same as application example 1.

Comparative application example 4

The difference from application example 1 is only that 17.1 parts of the cold water gel in comparative example 4 (i.e. 7.3 parts of xanthan gum, 7.3 parts of guar gum and 2.5 parts of sodium polyacrylate) is used in this comparative application example instead of 17.1 parts of the cold water gel in example 1, and the rest of the raw materials and the preparation method are the same as in application example 1.

Comparative application example 5

The difference from application example 1 is only that 17.1 parts of the cold water gel (namely 6.4 parts of carrageenan, 6.4 parts of guar gum and 4.3 parts of sodium polyacrylate) in comparative example 5 is used in the comparative application example instead of 17.1 parts of the cold water gel in example 1, and the rest of raw materials and the preparation method are the same as application example 1.

Taking 1mL of escherichia coli (ATCC 25922) diluent, adding the diluent into the microbial detection kits of application examples 1-7 and comparative application examples 1-5 respectively, mixing the diluent with culture medium powder in the kits, placing the mixture in a constant-temperature incubator at 37 ℃ for inverted culture for 24h, scoring the growth state of colonies, the growth speed of the colonies, the number of the colonies, the difficulty of picking the colonies and the difficulty of observation respectively, wherein the full score is 5, the 1 score is worst, the 2 score is poor, the 3 score is general, the 4 score is better, and the 5 score is best, recording the color of the colonies, and counting the data, wherein the results are shown in Table 2.

TABLE 2

From table 2, the following can be seen:

(1) the microbial detection kit prepared in application examples 1-3 has good comprehensive performance, the growth state of colonies is 5 minutes, the number of colonies is not less than 177, the difficulty degree of picking is 4 minutes, the grown colonies are red, and the difficulty degree of observation is 4 minutes;

(2) compared with application examples 1-3, the microbial detection kit prepared in application examples 4-6 is slightly poor in performance in some aspects, and the cold hydrogel content in application example 4 is high, so that the content of nutrient substances is low, and the growth state of colonies is slightly poor; in application example 5, the content of the cold hydrogel is low, and although the cold hydrogel does not affect the growth condition of bacterial colonies, the culture medium is soft and is not easy to pick; TTC is not added in the application example 6, so that the grown bacterial colony is white and is difficult to observe; the results show that the microbial detection culture medium only contains cold hydrogel, nutrient components and a microbial detection indicator, and when the corresponding addition amount is in a reasonable range, the microbial detection kit can achieve a good detection effect, the growth state of bacterial colonies is good, the number of bacterial colonies is large, and the microbial detection culture medium is easy to pick and observe;

(3) compared with application examples 1-3, the microbial detection kit of application examples 1-5 has poorer comprehensive performance, wherein xanthan gum is not added to the cold water gel of application example 1, and guar gum is not added to the cold water gel of application example 2; in comparative application example 3, sodium polyacrylate was not added to the cold water gel; the ratios of xanthan gum, guar gum and sodium polyacrylate in the cold water gel in comparative application example 4 were not in the optimum range; compared with the application example 5 in which carrageenan is used to replace guar gum, the growth state of the colony and the difficulty of picking and observing are all affected, which shows that the performance of the microorganism detection kit can be exerted to the maximum extent only by selecting the cold hydrogel with better comprehensive performance;

(4) compared with application examples 1-3, the microorganism detection culture medium is not fixed on the inner bottom wall of the culture dish through the non-setting adhesive in application example 7, so that the loss of the culture medium is caused, and the detection effect is the worst, which indicates that the culture powder is necessarily fixed on the inner bottom wall of the culture dish, so that the stability of the kit in transportation and storage can be ensured, and the optimal detection effect is achieved.

In addition, if the microorganism detection kit is prepared by adopting an autoclave sterilization mode, the culture medium is gelatinized, the nutrition cost in the culture medium is damaged, the growth of bacterial colonies is not facilitated, and the transparency of cold hydrogel is damaged by the gelatinized culture medium, so that the observation is not facilitated; agar is not soluble and gels at room temperature and therefore cannot be used to prepare a microbiological detection kit.

In conclusion, the cold water gel provided by the invention has the advantages that the cold water gel powder can be dissolved and gelatinized without being heated, the gelatinization speed is high, the gel strength is high, and the water retention and water absorption capacity is excellent; the microorganism detection culture medium containing the cold water gel has high gel speed and strong stability, is not influenced by environmental factors such as seasons and the like, and enables grown colonies to be red by adding an indicator, thereby being beneficial to observation; will little biological detection culture medium powder passes through the non-setting adhesive to be fixed at the inner diapire of culture dish, and the microbiological detection kit who makes has prolonged the shelf life of culture medium, has improved stability, and convenient to use only needs to add the sample solution that awaits measuring after diluting in the culture dish with the powder mixes into glue can, and adopt the culture method of pouring method, can be applied to the detection of aerobic bacteria and facultative anaerobe simultaneously, and than general flat plate detection method application scope is wider, and using value is higher.

The applicant states that the present invention is illustrated in detail by the above examples, but the present invention is not limited to the above detailed methods, i.e. it is not meant that the present invention must rely on the above detailed methods for its implementation. It should be understood by those skilled in the art that any modification of the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific modes, etc., are within the scope and disclosure of the present invention.