The effect of electron beam irradiation on the quality of nitrogen filled packaged cold fresh beef

Cheng Shuzhen, Zhang Chunhui, Zhang Jie, Jie Xinfang, Wang Zhidong*
(Institute of Agricultural Products Processing, Chinese Academy of Agricultural Sciences, Beijing 100193)

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Abstract: In order to investigate the effect of electron beam irradiation on the quality of nitrogen filled packaged cold fresh beef, six yellow cattle dorsal longissimus muscle were irradiated under a high-energy electron accelerator and stored at 4 ° C for 28 days. The changes in microbiological, biochemical, and sensory characteristics were evaluated under different irradiation doses (1.241, 2.300, 3.429 kGy) and storage times (0d, 7d, 14d, 19d, 22d, 25d, 28d). Compared with the control group, the total number of bacterial colonies in the experimental group significantly decreased. On day 0 of storage, the total number of bacterial colonies in the treatment group decreased by 0.766, 1.801, and 2.673 lg CFU/g, respectively, with significant differences (p<0.05); The storage loss of beef samples under electron beam irradiationcolor、 The pH value and fat oxidation did not have a significant effect, and the impact on TVB-N was relatively small; However, sensory evaluation analysis found that as the irradiation dose increased, the scores for color, odor, and acceptability decreased. Based on a comprehensive analysis of various quality indicators, low-dose electron beam irradiation of around 2.5 kGy can effectively kill microorganisms while ensuring the quality of beef and improving the shelf life of cold fresh beef.

Keywords: electron beam irradiation; Cold fresh beef; Nitrogen filled packaging; Microbiology; biochemistry; Sensory characteristics

In recent years, the variety and demand for meat products in China have significantly increased, and the meat industry has shown a vigorous development trend [1-3]. At present, the raw meat market in China mainly consists of three forms: hot fresh meat, cold fresh meat, and frozen meat. Compared with hot fresh meat and frozen meat, cold fresh meat has the advantages of soft texture, high nutritional value, and less loss of juice, so it is increasingly favored by consumers. However, during livestock slaughter, carcass segmentation, and meat processing, meat products are highly susceptible to microbial contamination, which can cause foodborne diseases. Although cold fresh meat is always in a low-temperature environment throughout the entire production and circulation process, which to some extent controls the growth of microorganisms, some cold tolerant microorganisms such as Salmonella and Listeria can still grow and reproduce normally, endangering the quality and safety of meat products, shortening their shelf life, and causing problems such as food poisoning.

At present, the main sterilization methods include pickling, freezing, high pressure, and modified atmosphere packaging, while there are relatively few sterilization methods that can be applied to cold fresh meat. Food irradiation, as a physical sterilization method, can effectively kill microorganisms without causing an increase in material temperature. Therefore, it is called "cold sterilization" technology and has been applied in various products in multiple countries. The types of radiation used for food irradiation mainly include electron beams generated by high-energy electron accelerators and gamma rays generated by 60Co or 137Cs. Both types of radiation are used in meat preservation, but existing research has shown that under the same irradiation dose conditions, electron beams with reducibility cause less oxidation effect on meat compared to gamma rays [5]. Therefore, in recent years, there has been an increasing amount of research and application of electron beam irradiation in meat products.

This experiment combines electron beam irradiation technology with nitrogen filled packaging to kill microorganisms while ensuring that the quality of cold fresh meat is not significantly affected, in order to solve the problem of short shelf life of cold fresh meat and provide reference for the application of electron beam irradiation in the preservation and storage process of cold fresh beef.

1 Materials and Methods
1.1 Materials and Reagents Cold Fresh Beef Dorsal Muscle (Outer Spine), purchased from ...
1.2 Instruments and equipment:DIGIEYE digital color measurement system: VERIVIDE company from the UK - Shanghai Yunding Trading Co., Ltd；. ...
1.3 Method
1.3.1 Sample Preparation
Meat yellow cattle were commercially slaughtered by Zhuochen Livestock Co., Ltd., cooled and acidified at 4 ° C for 3 days, and 6 fresh beef dorsal muscles were taken,
Remove visible fat, fascia, and tendon to cut meat slices with a length and width of 5cm × 4cm × 1cm to ensure uniformity of irradiation. Record each sample
Quality, 100% N2 packaging, placed in a 4 ° C freezer for irradiation the next day.
....
1.3.6 Color determination
Use DIGIEYE digital color measurement system (electronic eye) to measure the surface color of the sample, and place each treatment in the same sample tray
Conduct measurements. Randomly select the entire sample, record the average L * and a * values of each sample, measure each sample three times, and take the average value.
....
Color is a fundamental physical property of food and an important indicator for evaluating the quality of fresh meat, which affects consumers' purchasing desire. L * (brightness)
The parameter and a * (redness parameter) are two important parameters for evaluating the quality of fresh meat. Different electron beam irradiation doses on nitrogen filled packaged cold fresh beef
The color influence results are shown in Figures 3 and 4. From Figure 3, it can be seen that during the initial storage period, the brightness value L * of the irradiated group was lower than that of the control group,
But with the extension of storage time, the brightness value L * of the control group gradually decreased compared to the irradiation group, which may be due to the irradiation treatment group in the early stage of storage
The degree of myoglobin oxidation is greater. It can be seen that with the increase of storage time, the brightness values L * of both the control group and the treatment group gradually decrease,
The control group showed a greater decrease compared to the irradiation treatment group. There is a significant difference between the treatment groups with different doses, which increases with the extension of storage time
The color of the 2.5kGy treatment group is more vibrant.
....
3 Conclusion
After electron beam irradiation, the total number of bacteria in cold fresh beef significantly decreased, and the higher the irradiation dose, the better the sterilization effect. At 28
During the storage period, electron beam irradiation did not have a significant effect on the storage loss, color, pH value, and fat oxidation of cold fresh beef,
The impact on TVB-N is relatively small. However, in sensory evaluation, it was found that as the irradiation dose increased, the scores for color, odor, and acceptability decreased. knot
Based on the analysis of the above indicators, it is recommended that beef be irradiated with a low-dose electron beam of about 2.5kGy before storage to improve the quality of cold fresh beef
Shelf period.