Research and development of modern preservation te

Research and development of modern meat preservation technology

Abstract This paper summarizes the latest progress of meat preservation technology from seven aspects: fence technology, radiation preservation technology, microwave processing technology, food additive technology and so on

key words: Meat Preservation Technology fence effect

preface

as early as ancient times, when people harvested food with surplus, there was a need to store food. With the emergence and development of commodity economy, people process the harvested food for storage and carrying. In labor practice, people gradually master the processing methods of meat products such as curing, drying, fermentation and smoking

1. Frozen storage technology

food frozen storage is the science of using artificial refrigeration technology to reduce the temperature to preserve and process food. And the pre freezing technology has made great progress, which is mainly reflected in the following four aspects

1.1. The first is the form of frozen food, which has been continuously improved. At first, most of them were frozen in the form of overall large packaging, such as cattle, sheep, pigs and so on. In the future, in order to improve the freezing speed and quality, and save energy, the bulk raw food will be frozen and preserved in the form of processing, segmentation or small monomer. In recent years, we have focused on the development of small packaged frozen food

1.2. The second is the improvement of freezing method. Air blowing freezing device, pipe rack freezing device, low-temperature brine freezing device and horizontal or vertical plate freezing device that directly contacts metal plates and frozen objects for heat transfer have been developed to make the freezing temperature more uniform and the production efficiency more improved

1.3. Third, there are new breakthroughs in the refrigeration device as a cold wish, such as using liquid oxygen, liquid carbon dioxide and liquid Freon to spray and freeze directly, which greatly reduces the freezing temperature, greatly improves the speed, and further improves the quality of frozen products

1.4. Fourth, we have a further understanding of the temperature conditions of various food freezing, refrigeration, transportation, sales and other links. Arsdel et al. In the United States summarized the relationship between the temperature change of frozen food and the quality retention time through a ten-year study from 1948 to 1958, which is the t.t.t. concept of frozen food (time, temperature, tolerance time, temperature, food storage resistance). For most frozen food, the most economical and appropriate refrigeration temperature was proposed after determination. In recent years, due to the improvement of refrigeration device, the temperature of food freezing tends to be lower, and the refrigeration technology during food transportation has also been improved. In order to reduce the impact of temperature fluctuations on food quality in the process of food refrigeration, a continuous cold storage with low temperature treatment has been gradually formed between the production, circulation and consumption of food, that is, the position of the cold chain in people's life is obviously to prevent the production, sale and use of plastic shopping bags with a thickness of less than 0.025 mm across the country; In all supermarkets, shopping malls, bazaars and other commodity retail places, it is more and more important

2. Fence technology

this was proposed by Professor istner of the German meat Research Institute. He once presented a paper on "applying the 'barrier effect' theory and HACCP system to food planning" at the second Asian regional meat science and technology conference. At present, some people in industrialized countries are computerizing the "barrier effect" theory for food design. In other words, as long as the relevant parameters of food (such as water activity, pH value, heat treatment method and conditions of food, etc.) are input into the computer, the shelf life of food can be inferred. Various parameters can also be changed appropriately according to needs to make the food reach the ideal shelf life. Therefore, some people assert that the "barrier effect" theory will have an important impact on the development of food industry in the 21st century

2.1. Fence effect and fence technology

in order to achieve storability and health safety of meat products, there must be factors that can prevent the growth and reproduction of residual rot causing bacteria and pathogens. These factors are both processing and preservative methods, such as f (high temperature treatment), t (low temperature refrigeration), aw (reducing water activity), pH (acidification), eh (reducing redox value) CF (using competitive microorganisms such as lactic acid bacteria) and pres (using preservatives such as nitrite hydrochloric acid and sorbate, or smoking, etc.). We call these factors fence factors (harde pulls out the unique faces that appear in my mind), and these factors have an extremely synergistic effect that determines the stability of food microorganisms, which is the Hurdes effect

fence effect is the root of meat preservation. For a kind of storable and hygienic and safe meat, the complex interaction of fence factors such as aw, pH, t, pres controls microbial corruption, toxin production or beneficial fermentation. These factors work together to maintain the joint preservation of meat. We name it fence technology, or hardle technology

2.2. Internal balance and fence technology

an important phenomenon worthy of attention in meat preservation is the internal balance of microorganisms (homeostasis). Internal balance is the unity and stability of the internal environment of microorganisms under normal conditions. For example, whether for higher bacteria or general microorganisms, self-regulation of the internal environment pH value to keep it in a relatively small range of changes is a prerequisite for maintaining its activity. If the internal environment, that is, the internal balance is destroyed by food preservative factors (fences), microorganisms will lose their ability to grow and reproduce. Before the reconstruction of their internal environment, microorganisms will be in a stagnant period, or even die. Therefore, meat preservation is achieved by temporarily or permanently breaking the internal balance of microorganisms

the possibility of applying fence technology to meat preservation is not only based on the superposition of different fences in meat, but also the synergistic effect of these factors. If different fences in a meat product effectively target different targets in microbial cells, i.e. different targets, such as cell membrane, DNA, enzyme system, pH value, aw or eh, and break the internal environmental balance in several ways, effective fence synergy can be achieved. Therefore, the application of anti-corrosion fences with different strengths in food, through the synergistic effect of these fences, makes the food achieve microbial stability, which is more effective than the application of a single and high-strength fence, and is more conducive to food anti-corrosion and quality assurance. This "target co effect preservative" technology, which aims at different targets in microbial cells in food, is expected to become a promising research field

2.3. One of the examples of the application of fence technology is an improved Chinese dried meat product called "saf meat". Its aw value (0..70) is much higher than that of traditional dried meat (0.70), while its sugar content and salt content are lower than that of traditional dried meat. Its appearance, color, taste, tenderness and other sensory quality are better than traditional dried meat. Due to the increased strength of fences such as t (low temperature treatment), H (higher temperature sterilization), eh (vacuum packaging) during processing, new products with higher aw value still reach the shelf life of more than 3 months under the traditional uncooled condition of dried meat

3. Radiation preservation technology

at present, there are three kinds of radiation sources used in food, namely electron ray, X-ray and γ- Rays. The common characteristics of these three kinds of rays are: short wavelength (generally ~ m, commonly used ~), high enough energy to destroy covalent bonds and affect or destroy organisms; When transferring high energy to food, there is no obvious warming phenomenon, which can maintain the original characteristics of food; It's impossible not to continue innovation. It has strong penetration, especially γ- The penetration of rays, which can penetrate deep into the interior of food, makes the radiation dose uniform in all parts, and is completely suitable for the internal treatment of complete food and all kinds of packaged food. The penetration of X-ray and electron ray is weak, which can be used for food surface treatment and sheet food treatment

before complete sterilization by radiation, the meat must be preheated to 70 ~ 80 ℃ to inactivate the enzyme; Prevent tissue self decomposition, vacuum, sealed packaging and freezing to prevent the adverse effects of radiation on meat quality. Radiation should be carried out at -40 ℃. Beef, chicken, ham, sausage, etc. that have been completely sterilized by radiation will still have good color, aroma and taste even after being stored at room temperature for two years. The meat treated under hypoxia and anaerobic conditions is the same as fresh meat after three years of storage

4. Microwave treatment technology

the killing treatment of microorganisms by microwave energy is currently recognized as the classic thermal death, that is, the thermal denaturation of proteins and nucleic acids. Microwave energy heats objects instantly, which is 10 ~ 20 times faster than the traditional methods of surface heating, surface and internal heat transfer. Packaging products with microwave permeable n/pe bags can uniformly meet the requirements of high temperature treatment in a specific microwave field after instant treatment, with little damage to nutrients, flavor and color

microwave processing technology has great potential and broad development prospects because it reduces product losses, improves product quality, increases output, reduces energy consumption, and greatly reduces production costs

5. Food additive technology

5.1 Preservative: it mainly depends on its bacteriostasis to prolong the shelf life of meat products. Commonly used meat preservatives include sorbate/salt, benzoate/salt, lactic acid/salt, p-hydroxyphenyl methyl ester, etc., especially sorbic acid (or potassium sorbate) has inhibitory effect on mold, yeast and aerobic bacteria, especially the strongest effect on mold. It combines with the sulfhydryl (l-sh) of microbial enzyme system (mainly dehydrogenase), thereby destroying the enzyme system and inhibiting microbial growth and reproduction. Sorbic acid is an acidic preservative, and its effect is generally good at pH 5 ~ 6, which is close to