Method for effectively killing sub-lethal damage bacteria generated in thermal sterilization process

A thermal sterilization and sub-lethal technology, applied in the field of microorganisms, can solve the problems of sub-lethal damage of bacteria, secondary pollution of food, and no sub-lethal damage bacteria, so as to reduce the possibility and optimize the sterilization process

Inactive Publication Date: 2016-12-14
ZHEJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, studies have shown that heat treatment can induce a sublethal injury state in bacteria
Sublethal lesion bacteria cannot grow normally on commonly used media, so they can escape routine detection and cause false negative results
In the process of product storage and transportation, once the pathogenic bacteria in the sub-lethal state are under suitable environmental conditions, the sub-lethal bacteria can repair themselves and return to the normal state, so the bacteria in the sub-lethal damage state may cause food secondary damage. Secondary pollution, once it enters the human body, there will be potential hazards, which will bring serious hidden dangers to food safety and make the safety of thermal sterilization technology a challenge
[0003] Effectively killing the sublethal damage bacteria produced in the process of heat treatment is an important means to improve the effect of heat sterilization and enhance the safety of heat-processed food. However, the current effect of heat sterilization in food is only limited to the evaluation of bacteria that are completely killed by heat treatment. Sublethal damage bacteria produced during heat treatment are not involved

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] One heat combined with ultrasonic sterilization technology

[0023] (1) Preparation of bacterial suspension

[0024] The Staphylococcus aureus standard strain ATCC 25923 was inoculated in ordinary broth medium, and cultured on a shaker at 37°C until the logarithmic growth phase. Adopt 0.85% (mass percentage composition) aseptic normal saline to wash the thalli of logarithmic growth phase twice, resuspend, make thalline concentration be about 10 8 CFU / mL, as the bacterial liquid (bacterial suspension) to be induced; inoculate the standard strain of Staphylococcus aureus ATCC 25923 in common broth medium, and culture on a shaker at 37°C for 20 hours until the stationary phase.

[0025] (2) Joint processing

[0026] Experimental group: The Staphylococcus aureus suspension was treated with an ultrasonic SCIENTZ-IID sterilizing device. The specific steps were: put 30mL of the bacterial suspension into a glass ultrasonic tube, and an ultrasonic probe with a diameter of 10mm...

Embodiment 2

[0035] One heat combined with ultrasonic sterilization technology

[0036] (1) Preparation of bacterial suspension

[0037] Same as the method of step (1) in Example 1.

[0038] (2) Joint processing

[0039] The method of one step (2) in embodiment 1 is basically the same, only the processing time is changed to 7min.

[0040] Two detection

[0041] Same as the method of two in embodiment 1.

[0042] The results are as follows: the number of colonies of Staphylococcus aureus in the control group on the non-selective medium was 7.35log CFU / mL, the number of colonies on the selective medium was 6.20log CFU / mL, and the number of sublethal damage bacteria was 1.15log CFU / mL. The number of colonies of Staphylococcus aureus in the experimental group was 4.74log CFU / mL on non-selective medium, 4.70log CFU / mL on selective medium, and 0.04log CFU / mL of sublethal damage bacteria.

[0043] It can be seen that the method of the present invention effectively reduces the ratio of sublet...

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PUM

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Abstract

The invention discloses a method for effectively killing sub-lethal damage bacteria generated in a thermal sterilization process. The method comprises the following steps: enabling staphylococcus aureus washed with sterilized saline water to be suspended in the sterilized saline water to obtain bacterial suspension; then treating the bacterial suspension by using a thermal-ultrasonic combination sterilization method at the ultrasonic treatment frequency of 10 to 30 kHz, the treatment power of 500 to 700 w, the treatment duration of 5 to 7 min and the treatment temperature of 50 to 60 DEG C. According to the method, the possibility of restoration of the sub-lethal damage bacteria generated by thermal treatment under a proper condition is reduced, and the sterilization process is further optimized; the industrial application of the ultrasonic-thermal combination sterilization technology can be popularized favorably.

Description

technical field [0001] The invention relates to the technical field of microorganisms, in particular to a method for effectively killing sublethal damaged bacteria produced in a thermal sterilization process. Background technique [0002] Traditional thermal sterilization technology has been widely used in the food industry. It can kill various microorganisms, and the degree of sterilization can be accurately controlled. It is an effective sterilization method. However, studies have shown that heat treatment can induce bacteria to form a sublethal injury state. Sublethal lesion bacteria cannot grow and multiply normally on commonly used media, so they can evade routine detection and cause false negative results. In the process of product storage and transportation, once the pathogenic bacteria in the sub-lethal state are under suitable environmental conditions, the sub-lethal bacteria can repair themselves and return to the normal state, so the bacteria in the sub-lethal da...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): A23L3/00A23L3/30
CPCA23L3/00A23L3/30A23V2002/00A23V2200/10A23V2300/24A23V2300/48
Inventor 丁甜李娇刘东红马焱娜叶兴乾陈健初胡亚芹陈士国
Owner ZHEJIANG UNIV
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