Conduction oil formula of microbial agar culture medium and wet boiling method

Abstract

The invention discloses a heat-conducting oil formula of a microbial agar culture medium and a wet boiling method. The heat-conducting oil comprises the following components: deionized water and glycerol. According to the wet boiling method, irregularly-shaped silicon dioxide particles are added into a culture medium to serve as a physical anti-explosion boiling medium, so that a uniform gasification core is provided, and the risk of liquid bumping of the overheated culture medium can be effectively eliminated. And heat conduction oil bath (103-105 DEG C) is combined for indirect heating, so that a mild heat conduction environment is formed, and nutritional ingredient damage caused by local high temperature is avoided. In the process, continuously generated tiny bubbles play a natural stirring role, the culture medium is promoted to be uniformly heated, and the problems of agar sedimentation and coking and excessive decomposition of organic components are synchronously solved. According to the technology, the traditional sterilization bottleneck is broken through, the operation safety coefficient is remarkably improved while the sterilization effect is ensured, and a reliable solution is provided for preparation of a heat-sensitive culture medium.

Description

Technical Field

[0001] The present invention relates to a heat transfer oil formula and a wet boiling method for a microbial agar medium. Background Art

[0002] Food microbiological inspection, as a core technical means for food safety supervision, involves the detection of dozens of foodborne pathogenic bacteria such as Salmonella, Cronobacter, and Escherichia coli. According to the GB 4789 series of national standards, laboratories need to prepare media with different characteristics such as Salmonella chromogenic agar and violet red bile agar.

[0003] A microbial medium is a mixed nutrient for the growth, reproduction, metabolism, and maintenance of the vitality of microorganisms. Correct preparation of the medium is one of the most basic steps in microbial inspection, and all operations should be carried out in accordance with the regulations of standards or instructions. Usually, a matching heating method, such as autoclaving or boiling sterilization, is required to control the sterilization effect. After heating, it is cooled by an appropriate method to prevent overheating. However, for media such as violet red bile agar and Salmonella chromogenic agar that can only be sterilized by boiling, when preparing, it is generally necessary to heat while stirring on an electric furnace until the agar is completely melted before stopping stirring, and closely control the fire to prevent the medium from boiling violently and overflowing, and at the same time prevent the medium from sinking to the bottom and burning, so as to avoid the destruction of nutrients due to excessive heating.

[0004] If there is a slight difference in controlling the fire during the boiling process, a large amount of foam generated by the violently boiling medium often undergoes explosive ejection, and the scattered high-temperature medium seriously threatens the personal safety of the operator. In addition, the containers used for boiling are mostly conical flasks made of glass. During repeated use, the conical flasks will inevitably be damaged by collision, or damaged due to uneven heating during repeated boiling. Invisible damage will cause the conical flasks to burst suddenly during boiling, which further increases the operation risk during the boiling process of the medium. Summary of the Invention

[0005] Aiming at the above-mentioned disadvantages, the purpose of the present invention is to provide a heat transfer oil formula and a wet boiling method for a microbial agar medium. To achieve this purpose, the technical solution adopted by the present invention is: A heat transfer oil formula and a wet boiling method for a microbial agar medium, characterized in that the heat transfer oil includes the following components: deionized water, glycerol; each component of the heat transfer oil is included by mass percentage: deionized water 65% - 55%, glycerol 35% - 45%, and the sum of the mass percentages of the deionized water and the glycerol is 100%; the wet boiling method includes the following steps: a. Take an appropriate amount of irregularly shaped silica particles, clean them and dry them for later use. The particle size of the silica particles is preferably selected from 1 mm to 5 mm; b. Prepare the medium to be boiled according to the formula ratio, and place it in a suitable high-temperature resistant container. Add an appropriate amount of the pretreated silica particles, wrap the mouth of the high-temperature resistant container with a breathable sealing film and set aside. The high-temperature resistant container is preferably a conical flask made of high-temperature resistant borosilicate glass. The weighing amount of the silica particles is preferably selected from 5 g to 20 g; c. Inject an appropriate amount of the heat transfer oil into the constant temperature oil bath device, and after starting the machine, set the temperature control parameter of the constant temperature oil bath device to 103 °C - 105 °C; d. When the temperature of the heat transfer oil reaches the set temperature, immerse the conical flask in the heat transfer oil, and keep the height difference between the liquid level of the medium and the liquid level of the heat transfer oil ≤ 1 cm; e. Maintain the constant temperature treatment for 20 min - 30 min until the components of the medium are completely dissolved, and immediately transfer it to a suitable temperature for heat preservation and standby after taking it out.

[0006] Compared with the prior art, the beneficial effects of the present invention are: adding irregularly shaped silica particles as a physical anti-bumping medium to the medium, effectively eliminating the risk of violent boiling of the overheated medium liquid by providing a uniform gasification core. Combining indirect heating with a heat transfer oil bath (103 °C - 105 °C) to form a mild heat conduction environment and avoid the destruction of nutrient components caused by local high temperature. During this process, the continuously generated tiny bubbles play a natural stirring role, promoting uniform heating of the medium, and synchronously solving the problems of agar sedimentation and coking and excessive decomposition of organic components. This technology breaks through the traditional sterilization bottleneck, ensures the sterilization effect while significantly improving the operation safety factor, and provides a reliable solution for the preparation of heat-sensitive media. Detailed implementation mode

[0007] The following further elaborates on the present invention in conjunction with embodiments. Embodiment

[0008] When the present invention is applied to the sterilization of crystal violet neutral red bile salt agar medium, the following technical solutions are adopted to achieve the beneficial effects of the present invention: A heat transfer oil formula and wet boiling method for a microbial agar medium, characterized in that The heat transfer oil includes the following components: deionized water, glycerol; The components of the heat transfer oil are included by mass percentage: 55% of deionized water, 45% of glycerol; The wet boiling method includes the following steps: Take irregularly shaped silica particles with a particle size of 2 mm - 5 mm, clean them and dry them for later use; Prepare 300 ml of the medium to be boiled according to the formulation ratio, and place it in a conical flask made of heat-resistant borosilicate glass. Add 20 g of the pretreated silica particles, wrap the mouth of the heat-resistant container with a breathable sealing film, and set aside for later use; Inject an appropriate amount of the heat transfer oil into the constant temperature oil bath device. After starting the machine, set the temperature control parameter of the constant temperature oil bath device to 105 °C; When the temperature of the heat transfer oil reaches the set temperature, immerse the sealed heat-resistant container in the heat transfer oil, and keep the height difference between the liquid level of the medium and the liquid level of the heat transfer oil at 1 cm; Maintain the constant temperature treatment for 20 min until the components of the medium are completely dissolved. After taking it out, immediately transfer it to an appropriate temperature for heat preservation and standby.

[0009] After the crystal violet neutral red bile salt agar medium is sterilized by boiling, the medium is completely dissolved, with uniform texture, no agar sedimentation and coking, and the boiling phenomenon during heating is mild, without bumping and medium spraying.

[0010] Example 2: When the present invention is applied to the sterilization of Salmonella chromogenic agar medium, the following technical solutions are adopted to achieve the beneficial effects of the present invention: A heat transfer oil formulation and a wet boiling method for a microbial agar medium, characterized in that The heat transfer oil includes the following components: deionized water, glycerol; The components of the heat transfer oil are included by mass percentage: 60% of deionized water and 40% of glycerol; The wet boiling method includes the following steps: Take irregularly shaped silica particles with a particle size of 2 mm - 5 mm, clean them and dry them for later use; Prepare 300 ml of the medium to be boiled according to the formulation ratio, and place it in a conical flask made of heat-resistant borosilicate glass. Add 15 g of the pretreated silica particles, wrap the mouth of the heat-resistant container with a breathable sealing film, and set aside for later use; Inject an appropriate amount of the heat transfer oil into the constant temperature oil bath device. After starting the machine, set the temperature control parameter of the constant temperature oil bath device to 104 °C; When the temperature of the heat transfer oil reaches the set temperature, immerse the sealed heat-resistant container in the heat transfer oil, and keep the liquid level of the medium consistent with the liquid level of the heat transfer oil; Maintain a constant temperature treatment for 25 minutes until the components of the culture medium are completely dissolved. Immediately transfer it to an appropriate temperature for heat preservation and standby after taking it out.

[0011] After the Salmonella chromogenic agar medium was boiled and sterilized, the medium was completely dissolved, with uniform texture. There was no agar sedimentation and coking. The boiling phenomenon during heating was mild, and there was no violent boiling or medium spraying phenomenon.

[0012] Example 3: When the present invention is applied to the sterilization of xylose lysine deoxycholate agar medium, the following technical solutions are adopted to achieve the beneficial effects of the present invention: A heat transfer oil formula and wet boiling method for a microbial agar medium, characterized in that The heat transfer oil includes the following components: deionized water, glycerol; Each component of the heat transfer oil is included by mass percentage: 65% of deionized water, 35% of glycerol; The wet boiling method includes the following steps: Take irregularly shaped silica particles with a particle size of 2 mm - 5 mm, clean and dry them, and set aside; Prepare 200 ml of the culture medium to be boiled according to the formula ratio, and place it in a conical flask made of high-temperature resistant borosilicate glass. Add 10 g of the pretreated silica particles, wrap the mouth of the high-temperature resistant container with a breathable sealing film, and set aside; Take an appropriate amount of the heat transfer oil and inject it into the constant temperature oil bath device. After starting the machine, set the temperature control parameter of the constant temperature oil bath device to 103 °C; When the temperature of the heat transfer oil reaches the set temperature, immerse the sealed high-temperature resistant container into the heat transfer oil, and keep the height difference between the heat transfer oil liquid level and the culture medium liquid level at 1 cm; Maintain a constant temperature treatment for 30 minutes until the components of the culture medium are completely dissolved. Immediately transfer it to an appropriate temperature for heat preservation and standby after taking it out.

[0013] After the xylose lysine deoxycholate agar medium was boiled and sterilized, the medium was completely dissolved, with uniform texture. There was no agar sedimentation and coking. The boiling phenomenon during heating was mild, and there was no violent boiling or medium spraying phenomenon.

[0014] It should be understood that the described embodiments are only used to explain the present invention and are not used to limit the present invention. Any simplification or equivalent change based on the technical solution of the present invention belongs to the protection scope of the present invention.

Claims

1. Thermal oil formula and wet boiling method for microbial agar medium, characterized in that the thermal oil comprises the following components: deionized water, glycerol; each component of the thermal oil comprises, by mass percentage: 35% - 45% glycerol and 65% - 55% deionized water, and the sum of the mass percentages of the deionized water and the glycerol is 100%; the wet boiling method comprises the following steps: Take an appropriate amount of irregularly shaped silica particles, clean and dry them for later use. The particle size of the silica particles is preferably selected from 1 mm - 5 mm; a. Prepare the medium to be boiled according to the formula ratio, and place it in a suitable high-temperature resistant container. Add an appropriate amount of the pretreated silica particles, wrap the mouth of the high-temperature resistant container with a breathable sealing film and set aside. The high-temperature resistant container is preferably a conical flask made of high-temperature resistant borosilicate glass. The weighed amount of the silica particles is preferably selected from 5 g - 20 g; b. Inject an appropriate amount of the thermal oil into a constant temperature oil bath device, and set the temperature control parameter of the constant temperature oil bath device to 103 °C - 105 °C after starting the machine; c. When the temperature of the thermal oil reaches the set temperature, immerse the sealed high-temperature resistant container in the thermal oil, and keep the height difference between the liquid level of the medium and the liquid level of the thermal oil ≤ 1 cm; d. Maintain the constant temperature treatment for 20 min - 30 min until the components of the medium are completely dissolved, and immediately transfer it to a suitable temperature for heat preservation and standby after taking it out.