CN116458658A - Method for killing salmonella by low-energy X-rays - Google Patents

Method for killing salmonella by low-energy X-rays Download PDF

Info

Publication number
CN116458658A
CN116458658A CN202310263578.5A CN202310263578A CN116458658A CN 116458658 A CN116458658 A CN 116458658A CN 202310263578 A CN202310263578 A CN 202310263578A CN 116458658 A CN116458658 A CN 116458658A
Authority
CN
China
Prior art keywords
energy
salmonella
rays
low
ray
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202310263578.5A
Other languages
Chinese (zh)
Inventor
闫鹤
高雯暄
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
South China University of Technology SCUT
Original Assignee
South China University of Technology SCUT
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by South China University of Technology SCUT filed Critical South China University of Technology SCUT
Priority to CN202310263578.5A priority Critical patent/CN116458658A/en
Publication of CN116458658A publication Critical patent/CN116458658A/en
Pending legal-status Critical Current

Links

Classifications

    • A—HUMAN NECESSITIES
    • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
    • A23P—SHAPING OR WORKING OF FOODSTUFFS, NOT FULLY COVERED BY A SINGLE OTHER SUBCLASS
    • A23P30/00—Shaping or working of foodstuffs characterised by the process or apparatus
    • A—HUMAN NECESSITIES
    • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
    • A23L—FOODS, FOODSTUFFS, OR NON-ALCOHOLIC BEVERAGES, NOT COVERED BY SUBCLASSES A21D OR A23B-A23J; THEIR PREPARATION OR TREATMENT, e.g. COOKING, MODIFICATION OF NUTRITIVE QUALITIES, PHYSICAL TREATMENT; PRESERVATION OF FOODS OR FOODSTUFFS, IN GENERAL
    • A23L5/00—Preparation or treatment of foods or foodstuffs, in general; Food or foodstuffs obtained thereby; Materials therefor
    • A23L5/20—Removal of unwanted matter, e.g. deodorisation or detoxification
    • A—HUMAN NECESSITIES
    • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
    • A23L—FOODS, FOODSTUFFS, OR NON-ALCOHOLIC BEVERAGES, NOT COVERED BY SUBCLASSES A21D OR A23B-A23J; THEIR PREPARATION OR TREATMENT, e.g. COOKING, MODIFICATION OF NUTRITIVE QUALITIES, PHYSICAL TREATMENT; PRESERVATION OF FOODS OR FOODSTUFFS, IN GENERAL
    • A23L5/00—Preparation or treatment of foods or foodstuffs, in general; Food or foodstuffs obtained thereby; Materials therefor
    • A23L5/30—Physical treatment, e.g. electrical or magnetic means, wave energy or irradiation
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
    • Y02A50/30—Against vector-borne diseases, e.g. mosquito-borne, fly-borne, tick-borne or waterborne diseases whose impact is exacerbated by climate change

Landscapes

  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Food Science & Technology (AREA)
  • Polymers & Plastics (AREA)
  • Health & Medical Sciences (AREA)
  • Nutrition Science (AREA)
  • Apparatus For Disinfection Or Sterilisation (AREA)

Abstract

The invention discloses a method for killing salmonella by low-energy X-rays. The low energy X-rays employed in the present invention have a higher Linear Energy Transfer (LET) and relative biological effect (BRE), and have a higher absorption at the same photon flux ("dose effect"). The low-energy X-rays under investigation have cut-off energies of 50, 100 and 150keV respectively, which are produced by an X-ray cabinet type radiation instrument, and are simple and safe to operate and controllable. The low-energy X-ray has remarkable inactivating effect on the salmonella in PBS and chicken, and can inactivate the salmonella to a detection limit below (< 1.0CFU lg/mL) in a 1000Gy dose. The irradiation method for effectively killing salmonella in chicken provided by the invention is simple to operate, safe and reliable, does not need large-scale lead shielding, highlights the applicability of a cheaper and safer low-energy X-ray source to sterilization application, and promotes the development of food irradiation technology.

Description

Method for killing salmonella by low-energy X-rays
Technical Field
The invention relates to the technical field of sterilization of salmonella of food-borne pathogenic bacteria, in particular to a method for killing salmonella by using low-energy X-rays.
Background
Microbial contamination has been an important factor in threatening food safety. At present, the food safety problem in China is more prominent, and laws and regulations related to food-borne pathogenic bacteria are lagged behind those in developed countries, so that the problem of overcoming food-borne diseases caused by microbial pollution becomes one of the modern public health problems. Salmonella (Salmonella) is a common food-borne pathogenic bacterium in chicken processing and production, a gram-negative bacterium of the Enterobacteriaceae family, widely distributed in nature, and more than 2500 serotypes have been found so far for both Salmonella Pogostemonis and Salmonella enterica. Salmonella is classified by WHO as one of four important human and animal co-suffering food-borne pathogenic bacteria, and adverse reactions such as fever, vomiting and diarrhea are usually caused. There are several different ways to infect salmonellosis, of which more than 95% of human infection cases are caused by food, such as inadequate cooking of contaminated raw food or cross-contamination after cooking. Therefore, the food-borne diseases caused by salmonella pose a great threat to human health, and also pose a great impediment and loss to the health and economic development of human communities.
The application of proper sterilization technology in food processing is a key for preventing and controlling microbial pollution and ensuring food quality and safety. With the increasing abundance of national living eating habits, more and more people in China begin to accept and enjoy less processed foods, and the nutrients and the taste of the foods are expected to be better preserved in the processing process, and the foods which are not subjected to heat processing treatment are easy to carry pathogenic bacteria. Therefore, there is a need to develop an efficient non-thermal decontamination technique to improve the safety and quality of raw meat-based food products. However, the sterilization capacity of different non-thermal sterilization techniques varies and can have varying degrees of impact on food nutrition and quality: the residue of chemical reagent not only endangers human health, but also brings a certain burden to environmental treatment, and does not meet the requirements of green food processing; the autoclaving technique can adversely affect the texture, color and moisture of the meat; meanwhile, other sterilization technologies (such as ultraviolet sterilization and microwave sterilization) also have the risk of incomplete sterilization.
The irradiation technology is one of the emerging non-thermal sterilization technologies in the field of food processing, can effectively kill pathogenic microorganisms in food, and becomes a research hot spot in the food industry in recent years. The irradiation is to induce ionization of biomacromolecule such as nucleic acid, enzyme and amino acid in food matrix or microorganism by utilizing penetrability of X-ray, gamma ray or electron beam to food, and induce water in food to generate free radicalThereby destroying the structure and function of bacteria and achieving the aim of killing microorganisms and pests in food. The technology has broad spectrum and high efficiency, has no hidden trouble of toxicity, microorganism, radiochemistry and other safety problems under the specified dosage, and can ensure the quality and nutrition of food to be prevented from being destroyed to the maximum extent. However, conventional radionuclides (e.g 60 Co and 137 cs), energy loss (radioactive sources typically have a short half-life and need to be replenished periodically), and nuclear pollution, making the construction and maintenance costs of traditional irradiation technology sites relatively high. In order to overcome the pain spots mentioned above, X-rays or electron beams generated by non-radioactive nuclear mechanical source applicators have been widely appreciated and used in recent years. X-ray radiation exhibits the union advantage of combining the other two rays: the method has better technical safety and controllability; has photon characteristics similar to gamma rays, i.e., higher energy, penetration and sterilization effects than electron beams. Therefore, the X-ray irradiation sterilization is a novel method for selectively inactivating pathogenic microorganisms and viruses.
In recent years, low-energy X-rays (the radiation energy is in KeV) are considered to be more suitable for surface sterilization, and the sterilization effect is superior to gamma rays, electron beams, and high-energy X-rays. Low energy X-rays have higher Linear Energy Transfer (LET) and relative biological effects (BRE), and higher absorption at the same photon flux ("dose effect"); at the same time, its softness reduces the risk of damaging the sterilized materials, and also makes it possible to use them safely in production lines without causing danger to staff or the need for large-scale lead shielding, a promising food sterilization method. Studies have shown that a higher electron density of low energy radiation (e.g., low energy X-rays) can cause more interactions with electrons in biomolecules, resulting in a larger ionization cross-section, and more ionization and excitation events are generated from the radiation as it interacts with the biomolecules. In addition, the process of energy transfer between low energy X-rays and molecules in cells is more efficient, thereby causing a series of cascade reactions, producing large amounts of free radicals and other chemical reactants, deepening the production of biomolecules such as DNA, proteins and lipids within cellsThe degree of injury, and thus the vital activity of the cells. Jeong et al showed that using 70keV low energy X-rays, E.coli O157 in lettuce: dof H7 Strain 10 The value (initial bacterial count reduced by 90%) was 40+ -1 Gy, compared to D using gamma rays 10 The value was 3.4 times lower (136 Gy) (Sanghyup Jeong, marks Bradley-P, ryser eliot-T, et al the effect of X-ray irradiation on Salmonella inactivation and sensory quality of almonds and walnuts as a function of water activity [ J)]International Journal of Food Microbiology,2012,153 (3): 365-371.). The "dose efficiency" of low energy X-rays to microorganisms is determined by their energy spectrum (radiant energy). Ha et al found that X-rays at 50KeV were 2 times more efficient at inactivating Bacillus pumilus spores than at 150keV, 3 times more efficient at 100 keV; and the bacterial count was reduced by 12l g CFU/g (corresponding to 10 required for sterilization of medical instruments) under 1kGy of 50KeV of X-ray irradiation -6 Sterility assurance level), i.e., the dosage required for X-rays is an order of magnitude less than gamma rays in the same sterilizing effect (Thi-Mai-Hoa Ha, yong Derrick, lee Elizabeth-Mei-Yin, et al Activity and inactivation of Bacillus pumilus spores by kiloelectron volt X-ray irradication [ J ]]PloS one,2017,12 (5): e 177571.). However, there is no detailed report to compare the inactivation effect of low energy X-rays on salmonella at different energies. In order to reach the food sanitation standard (effectively reduce the adhesion amount of microorganisms), the accurate setting of the sterilization dose before the food irradiation is a key for ensuring the qualification of the sterilization processing of fresh meat, and the environment in which the microorganisms are positioned is also one of key factors influencing the irradiation sterilization efficiency.
Therefore, the use of low energy X-ray irradiation technology to kill gram negative bacteria, especially salmonella in chicken, requires setting gradient X-ray source parameters based on the difference in relative biological efficacy of different energy X-rays on microorganisms to determine a suitable salmonella lethal kinetics method.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provides a method for killing salmonella by using low-energy X-rays.
The invention aims at realizing the following technical scheme:
the invention provides a method for killing salmonella by low-energy X-rays, which comprises the following steps:
(1) Irradiating the salmonella pure culture sample with X-rays;
(2) The salmonella-inoculated chicken sample was irradiated with X-rays.
The X-rays are continuous light sources.
When the X-ray is used for irradiation, a 1.0mm copper (Cu) filter is pumped out from an X-ray irradiation group with the energy less than or equal to 150kV so as to obtain high-proportion low-energy X-rays and high dose rate.
Further, in the step (1), the energy of the X-ray irradiation is 50-150 kV.
Further, in the step (1), the dose of the X-ray irradiation is 100-1000 Gy.
Further, in the step (1), the dose rate of the X-ray irradiation is 291.50 to 295.23mGy/s.
Further, in the step (1), the time of the X-ray irradiation is 343 to 3430s.
Preferably, in the step (1), the energy of the X-ray irradiation is 50kV, and the dosage is 500-600 Gy.
Further, in the step (2), the energy of the X-ray irradiation is 50-150 kV.
Further, in the step (2), the dose of the X-ray irradiation is 250-1000 Gy.
Further, in the step (2), the dose rate of the X-ray irradiation is 291.50 to 295.23mGy/s.
Further, in the step (2), the time of the X-ray irradiation is 343 to 3430s.
Preferably, in the step (2), the energy of the X-ray irradiation is 150kV, and the dosage is 750-1000 Gy.
The dose, the dose rate and the time satisfy the following relation:
dose = dose rate time
In order to reduce unnecessary dose loss by spreading the irradiated sample over the whole illumination range, the distance between the light source and the sample to be treated is preferably 10cm when the X-rays are used for irradiation in the step (1) and the step (2).
The invention relates to a method for killing salmonella by using X-rays, which is a method for killing salmonella by using high-proportion low-energy X-rays. The invention obtains a higher proportion of low-energy continuous X-rays by removing a Cu filter of 1.0 mm. The filter is utilized to filter and block a large amount of low-energy X rays, more energy gradients are added, and the effectiveness of the low-energy X rays in killing the pure culture salmonella is verified by comparing the sterilization effect of the different-energy X rays on the pure culture salmonella; meanwhile, the process optimizes the irradiation energy and the dosage range by comparing the decline condition of pure culture/chicken inoculation salmonella under different dosage gradients of low-energy irradiation, and provides valuable information for future X-ray parameter application and microbial inactivation prediction.
Compared with the prior art, the invention has the following advantages and beneficial effects:
(1) The invention innovatively applies the low-energy X-ray with high BRE value/LET value to the irradiation power sterilization method for killing salmonella, has small irradiation dosage and obvious inactivation effect, can thoroughly kill salmonella, and can inactivate salmonella to a detection limit below (< 1.0CFU lg/mL).
(2) The invention has the effect of controlling and preventing the risk of salmonellosis, is also suitable for killing and regulating salmonella in fresh chicken, and provides scientific basis for the development of X-ray sterilization technology.
(3) The irradiation method for killing salmonella in chicken provided by the invention is simple to operate, safe and reliable, does not need large-scale lead shielding, and highlights the applicability of cheaper and safer low-energy X-ray sources to sterilization application so as to better promote the development of food irradiation technology.
Drawings
FIG. 1 is a schematic diagram of a 30-320 kV X-ray generating device.
Wherein: 1-E 1 Low voltage power supply, 2-X-ray tube, 3-E 2 High-voltage power supply, 4-milliamp meter, 5-beryllium window, 6-aluminum filter sheet, 7-lifting table, 8-ionization chamber, 9-shielding device and 10-coldBut the system.
FIG. 2 is a linear function of dose rate in air at 10cm from the light source as a function of current.
FIG. 3 shows the effect of different energy X-rays on killing pure culture salmonella.
FIG. 4 is the effect of low energy X-rays on killing pure culture salmonella.
Figure 5 is the effect of low energy X-rays on killing salmonella in chicken.
Detailed Description
The present invention is described in further detail below with reference to examples and drawings, but the practice and protection of the present invention are not limited thereto. It should be noted that the following processes, unless specifically described otherwise, are all as would be realized or understood by one skilled in the art with reference to the prior art. The reagents or apparatus used did not identify the manufacturer and were considered conventional products available commercially.
Sample treatment:
test strain: the salmonella species used in the examples were salmonella enteritidis ATCC 50335, H9812 and S010, respectively. Wherein ATCC 50335, H9812 is provided by the cantonese province collection of microorganism strains; s010 was isolated from 9 cities in Hebei province in North China by a national food borne pathogen monitoring system (National Active Foodborne Pathogens Surveillance System) (Yan H, li L, alam M J, et al, prevvalance and antimicrobial resistance of Salmonella in retail foods in northern China [ J ] International journal of food microbiology,2010,143 (3): 230-234.).
Preparing chicken samples: the chilled fresh chicken used in the examples was taken from an on-line platform with an average mass of 360.+ -.100 g and transported to the laboratory at 4 ℃ refrigeration over 1 hour. Excess fat and fascia on the surface of fresh chicken breast was removed with sterile scissors and cut under aseptic conditions to uniform shape and size (2 cm x 1 cm), weighing about 5 grams each, and stored at 4 ℃ until use (within a few hours).
The preparation method of the salmonella pure culture bacterial suspension comprises the following steps: streaking fungus solution in glycerol pipe at-80deg.C, inoculating onto trypticase Soy peptone (TSB) agar plate, and culturing at 37deg.CCulturing for 18-24 h. And (3) respectively picking single bacterial colonies into a 10mL TSB culture tube, and culturing for 18-24 hours at the temperature of 37 ℃ and the rotating speed of 100rpm to obtain a bacterial culture solution in a platform stage. Equal amounts of the three Salmonella cultures were mixed in a 50mL centrifuge tube, centrifuged (7000 rpm, 10min at 4 ℃), and the supernatant was discarded. The bacterial cell pellet was resuspended in 10mL of 0.1% sterile peptone water to adjust the bacterial cell concentration to 10 8 ～10 9 CFU/mL. The prepared salmonella pure culture bacterial liquid is packaged in a 2.0mL centrifuge tube.
Chicken inoculation: inoculating by soaking method. 5g of chicken sample was transferred to a beaker containing 200mL of Salmonella pure culture broth, sealed and shaken at 25℃at 80rpm for 20min. Taking out the sample from the soaking solution, draining for 10-15 s, aseptically placing the sample on a culture dish, placing the culture dish on an ultra-clean workbench, airing for 30min to attach bacteria, and inoculating the bacteria with the concentration of 10 6 ～10 8 CFU/mL, placing the sample into a sterile sealed bag, and transporting the sample at a low temperature until the sample is subjected to X-ray irradiation treatment.
Description of the radiator and generation of low energy X-rays:
the X-rays in the examples were produced from CIX3 bipolar cermet X-ray tubes of a CIX-series X-ray cabinet irradiation instrument (Xstrahl, UK). The X-ray generating apparatus has a structure as shown in fig. 1, and includes: 1-E 1 Low voltage power supply, 2-X-ray tube, 3-E 2 The high-voltage power supply, 4-milliampere meter, 5-beryllium window, 6-aluminum filter sheet, 7-elevating platform, 8-ionization chamber, 9-shielding device and 10-cooling system. The X-ray irradiation system comprises an X-ray tube (the light source can generate X-rays of up to 4.2kW, has an adjustable voltage of 30-320 kV and an adjustable current of 0-30 mA), a control panel, an ionization chamber, a lifting table, a shielding system and a cooling system. An 0.8mm beryllium window was used to focus the X-rays and ensure effective dose rate, dose uniformity and effective radiation penetration. In the ionization chamber, the dose rate AT a given X-ray source parameter was measured in real time using an AT1123 dosimeter (ATOMTEX, bellus). Two main parameters (voltage and current) of the X-ray source corresponding to the position 10cm away from the light source are adjusted to determine the fixed dose rate of 291.50-295.23 mGy/s. The voltage applied to the X-ray source (in kilovolts or kilovolts) will determine the X-ray emission energy (inKilo electron volts or keV). On the other hand, the current is proportional to the number of X-ray photons emitted and thus to the dose rate.
Low energy X-ray method for treating salmonella:
placing salmonella pure culture bacterial liquid and salmonella inoculated chicken samples on a lifting table, as shown in fig. 1, arranging the lifting table 7 in a shielding device 9, adjusting the height of the lifting table 7 according to a pre-experiment optimization result so as to irradiate all samples (10 cm away from a light source) with X-rays, pumping out an aluminum filter 6 to obtain high-proportion low-energy X-rays and high-dose rate, adjusting a voltage 3 to change an X-ray energy spectrum, and adjusting a current 4 to meet the requirement that the gradient energy X-rays output fixed dose rate is 291.50-295.23 mGy/s. At each irradiation dose, three parallel tubes of samples were taken from the ionization chamber. For pure culture of Salmonella bacteria, 100. Mu.L of bacteria were prepared in 0.1% PW for each sample as serial 10-fold dilutions, appropriate dilutions were selected, 100. Mu.L of dilutions were plated on TSA plates and incubated in an incubator at 37℃for 18-24 h (to recover damaged cells). For salmonella inoculated chicken samples, 5.0g of the sample was placed in a sterile homogenization bag, and then 50mL of sterile 0.1% PW was added. Samples were homogenized for 1min using an HX-4 tap sterile homogenizer. Serial 10-fold dilutions were prepared in 0.1% PW. A suitable dilution is selected, 100. Mu.L of the dilution is spread on a Xylolysinodeoxycholate (XLD) agar plate (selective medium) and incubated for 18-24 h at 37℃in an incubator. Colonies were counted and the results expressed as log CFU/mL. Each sample treatment was performed in 3 biological replicates and each dilution was repeated 3 times.
Wherein the HX-4 flap type sterile homogenizer is from Shanghai analysis industries Co., ltd; SHP-250 incubator is from Guangzhou Kokai Instrument Co.
Data analysis:
experimental data were processed and analyzed using GraphPad Prism 8.0.1 software (GraphPad software inc., san Diego, USA).
The following examples are used to describe embodiments of the present invention in detail, so as to fully explain and implement the implementation process of how the present invention is applied to technical means to solve technical problems.
Example 1
Inactivation influence experiment of X-rays with different energies on pure culture salmonella
The voltage applied to the X-ray source (in kilovolts or kV) will determine the cutoff energy (measured in kilo-electron volts or keV) of the emitted X-rays. In view of the lower limit of the blocking voltage of the 1.0mm Cu filter under the pre-experiment being 70kV, the experimental voltages are adjusted to be 50kV, 100kV, 150kV, 100kV+Cu, 150kV+Cu, 200kV+Cu, 250kV+Cu and 300kV+Cu, namely a series of energy gradients are set. The two main parameters that determine the dose rate of X-rays at a given location are high voltage and current, which is a linear function of dose rate as shown in fig. 2, and current is proportional to the number of X-rays emitted and thus to the dose rate.
Performing experiments according to the method for treating salmonella by using the X-rays, placing a sample at a position 10cm away from a light source, and controlling the irradiation dose rate of the X-rays to be 291.50-295.23 mGy/s; the irradiation dose of the light source is 200Gy, 400Gy and 600Gy. The inactivation of pure culture salmonella under different energy X-ray treatments is shown in figure 3. When the irradiation energy is lower (100 kV and 150 kV), the lethality of the X-ray to the pure culture salmonella is improved along with the increase of the dosage, and the method is specifically expressed as follows: the initial inoculation amount of pure culture salmonella is about 7.47-7.56 log CFU/mL, and when the irradiation dose is 400Gy, the colony number of salmonella in a 50kV irradiation group is reduced below the detection limit; when the irradiation dose was 600Gy, the numbers of salmonella colonies in the 100kV, 150kV, 100kV+Cu, 150kV+Cu, 200kV+Cu, 250kV+Cu and 300kV+Cu irradiation groups were reduced to 2.49, 1.62, 6.99, 7.07, 6.49, 6.78, 6.48log CFU/mL, respectively. The low-energy X-ray is added to improve the inactivation effect of salmonella; alternatively, in the 100kV+Cu, 150kV+Cu, 200kV+Cu, 250kV+Cu and 300kV+Cu irradiation groups, the mortality rate of salmonella is extremely low, and the sterilization effect is not obvious.
Example 2
Experiment of influence of low-energy X-ray on effect of irradiation on killing pure culture salmonella
Experiments were performed according to the above method of X-ray treatment of salmonella, wherein: the X-ray energy (voltage) is set to be 50kV, 100kV and 150kV; the light source irradiation dose is 100Gy, 200Gy, 300Gy, 400Gy, 500Gy, 600Gy, 800Gy, 1000Gy. FIG. 4 shows the inactivation of Salmonella pure culture broth under low energy X-ray (.ltoreq.150 kV) treatment: the initial inoculation amount of pure culture salmonella is about 8.71log CFU/mL, and when the irradiation energy is 50kV and the irradiation dose is 200Gy and 500Gy, the salmonella can be reduced by 3.79 log CFU/mL and 6.87log CFU/mL respectively, and the mortality rate of the salmonella can reach 99.98378% and 99.99999% respectively; when the irradiation energy is 100kV and the irradiation doses are 200Gy, 600Gy and 800Gy, the salmonella can be reduced by 2.99, 5.22 and 7.11log CFU/mL, and the mortality rate of the salmonella can reach 99.89767%, 99.99940% and 99.99999% respectively; when the irradiation energy is 150kV and the irradiation doses are 200Gy, 600Gy and 800Gy, the salmonella can be reduced by 2.00, 6.33 and 6.81log CFU/mL, and the mortality rate of the salmonella can reach 98.99307%, 99.99995% and 99.99998% respectively. Thus, salmonella is reduced linearly with increasing irradiation dose. When using 50kV energy X-rays, the mortality of salmonella by ionizing radiation increases with increasing dose, and when doses >500Gy, pure culture salmonella can be killed below the detection limit (< 1log CFU/mL), probably because low energy X-rays have higher les and BRE, resulting in more yield of DNA Double Strand Breaks (DSBs) in cells at unit dose, thereby accelerating the inactivation efficiency of microorganisms.
Example 3
Experiment of influence of low-energy X-rays on effect of irradiation on killing salmonella vaccinated with chicken
Experiments were performed according to the above method of X-ray treatment of salmonella, wherein: the X-ray energy (voltage) is set to be 50kV, 100kV and 150kV; the irradiation dose of the light source is 250Gy, 500Gy, 750Gy and 1000Gy. The inactivation of Salmonella after low energy X-ray treatment (.ltoreq.150 kV) is shown in FIG. 5. With increasing irradiation dose, the killing effect on salmonella increases significantly, and the initial inoculum size of salmonella in chicken is about 5.67log CFU/mL. When the irradiation dose is 1000Gy, X rays of 50kV, 100kV and 150kV can respectively reduce the salmonella amount by 4.03, 4.80 and 5.67log CFU/mL, the mortality rate of the salmonella can respectively reach 99.99067%, 99.99842% and 99.99979%, and when the dose is >1000Gy, the salmonella amount of chicken inoculation can be killed to be below the detection limit (< 1.0CFU lg/mL). The possible reason is that the higher the X-ray energy is, the stronger the penetration ability to chicken meat is, and the more thorough the sterilization effect is.
The foregoing is merely illustrative of specific embodiments of the present invention, and the scope of the invention is not limited thereto, but any changes or substitutions that do not undergo the inventive effort should be construed as falling within the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope defined by the claims.

Claims (10)

1. A method for killing salmonella by low-energy X-ray irradiation, which is characterized by comprising the following steps:
(1) Irradiating the salmonella pure culture sample with X-rays;
(2) The salmonella-inoculated chicken sample was irradiated with X-rays.
2. The method of claim 1, wherein in step (1), the energy of the X-ray irradiation is 50-150 kV.
3. The method of claim 1, wherein in step (1), the dose of the X-ray irradiation is 100Gy to 1000Gy.
4. The method of claim 1, wherein in step (1), the X-ray irradiation dose rate is 291.50 to 295.23mGy/s.
5. The method of claim 1, wherein in step (1), the X-ray irradiation is performed for a period of 343 to 3430 seconds.
6. The method of claim 1, wherein in step (2), the energy of the X-ray irradiation is 50-150 kV.
7. The method of claim 1, wherein in step (2), the dose of the X-ray irradiation is 250Gy to 1000Gy.
8. The method of claim 1, wherein in step (2), the X-ray irradiation dose rate is 291.50 to 295.23mGy/s.
9. The method of claim 1, wherein in step (2), the X-ray irradiation is performed for a period of 343 to 3430 seconds.
10. A method of killing salmonella by low energy X-rays according to any one of claims 1 to 9, wherein the method is capable of inactivating salmonella below the limit of detection.
CN202310263578.5A 2023-03-17 2023-03-17 Method for killing salmonella by low-energy X-rays Pending CN116458658A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202310263578.5A CN116458658A (en) 2023-03-17 2023-03-17 Method for killing salmonella by low-energy X-rays

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202310263578.5A CN116458658A (en) 2023-03-17 2023-03-17 Method for killing salmonella by low-energy X-rays

Publications (1)

Publication Number Publication Date
CN116458658A true CN116458658A (en) 2023-07-21

Family

ID=87172529

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202310263578.5A Pending CN116458658A (en) 2023-03-17 2023-03-17 Method for killing salmonella by low-energy X-rays

Country Status (1)

Country Link
CN (1) CN116458658A (en)

Similar Documents

Publication Publication Date Title
Kim et al. Using UVC light-emitting diodes at wavelengths of 266 to 279 nanometers to inactivate foodborne pathogens and pasteurize sliced cheese
Li et al. A review on recent development in non-conventional food sterilization technologies
US3779706A (en) Process for bulk sterilization, minimizing chemical and physical damage
Dasan et al. Surface decontamination of eggshells by using non-thermal atmospheric plasma
Maeda et al. Inactivation of Salmonella by nitrogen gas plasma generated by a static induction thyristor as a pulsed power supply
Kim et al. Effect of inactivating Salmonella Typhimurium in raw chicken breast and pork loin using an atmospheric pressure plasma jet
Jackson et al. Gamma irradiation and the microbial population of soils at two water contents
Wang et al. Inactivation efficacy and mechanisms of atmospheric cold plasma on Alicyclobacillus acidoterrestris: Insight into the influence of growth temperature on survival
CN116458658A (en) Method for killing salmonella by low-energy X-rays
RU2729813C2 (en) Method of surface disinfection of eggs
Borick et al. Effects of continuous and interrupted radiation on microorganisms
Amiri et al. Effect of electron beam irradiation on survival of Escherichia coli O157: H7 and Salmonella enterica serovar thyphimurium in minced camel meat during refrigerated storage
CN102948454B (en) Method of applying X-ray to sterilize and preserve bass slices and application thereof
Labaw et al. Development of bacteriophage in x-ray inactivated bacteria
JPH06317700A (en) Electron beam radiating device
Dyer et al. Radiation survival of food pathogens in complex media
Tarpley et al. RADIATION STERILIZATION I: The Effect of High Energy Gamma Radiation from Kilocurie Radioactive Sources on Bacteria
Curry et al. The effect of high-dose-rate X-rays on E. coli 0157: H7 in ground beef
Focea et al. Bacteria response to non-thermal physical factors: A study on Staphylococcus aureus
Djurdjevic-Milosevic et al. The survival of Escherichia coli upon exposure to irradiation with non-coherent polychromatic polarized light
Proctor et al. Radiosensitivity of Bacillus thermoacidurans under different environmental conditions
Nickerson et al. Public health aspects of electronic food sterilization
Pillai Accelerator technologies for food safety and food quality: Response of microbial populations to ionizing technologies.
Borsa et al. Recovery of microorganisms from potentially lethal radiation damage
Sommers et al. Inactivation of avirulent Yersinia pestis in Butterfield's phosphate buffer and frankfurters by UVC (254 nm) and gamma radiation

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination