The function of vacuum shrink packaging in fresh meat packaging

Although packaging meat in shrink bags in European countries and the United States is a common common standard and plays a very important role in the meat industry, such packaging systems are not common in Asia.

The preservation period of fresh meat in the natural environment is very short. Many factors can cause the deterioration of the meat quality. Countries in the industry are all looking for ways to extend the shelf life. Nowadays, the meat industry in Europe and America controls the temperature, hygiene and packaging (shrink vacuum Three basic elements were successfully packaged and three months of beef and 45 days of pork were successfully preserved. The impact of shrinking vacuum bag packaging on the shelf life of preserved meat was discussed in particular in light of the difficulties encountered in handling preserved meat:

1 weight loss

Unpackaged fresh meat will lose weight due to water loss. The longer the storage time, the greater the weight loss. Loss of weight will not only darken the meat and cause the appearance to deteriorate, but will also directly result in the loss of the profit of the manufacturer. If it can be sealed with a shrink bag vacuum package, The water is preserved so that dehydration does not occur.

2 microorganisms

2.1 mold

It will make the surface of fresh meat green, and mold only grows in the presence of oxygen, so vacuum packaging can prevent the growth of mold.

2.2 Bacteria

According to the need for oxygen when growing, it can be divided into three categories: aerobic bacteria, anaerobic bacteria, and anaerobic bacteria:

(1) Aerobic bacteria: Their life must be maintained by oxygen. It is the most abundant category in the environment. It is also a major factor that causes fresh meat to be corrupted. It can cause meat spoilage and produce surface mucus, which can be pumped by vacuum. Separation of oxygen with high gas barrier vacuum packaging prevents it from growing.

(2) Anaerobic bacteria: They must survive under anaerobic conditions, are not easily detected, and have no odor (micro) gas production. Vacuum cannot inhibit their growth, but low temperatures (<4°C) can stop them from growing. Therefore, low temperature storage combined with strict hygiene control can effectively reduce the chance of causing damage.

(3) Passive anaerobic bacteria: They can survive in the presence or absence of oxygen, and they can also grow in low-temperature environments. They can produce odors in the production gas. They must adopt strict hygienic procedures and cryopreservation to reduce the number of initial bacteria and delay growth and reproduction. speed.

3 color change

The quality of fresh meat is determined by the subjective judgment of consumers. Under natural circumstances, fresh flesh should be dark purple, and exposure to oxygen will present the bright red that most consumers love. The color change of fresh meat is mainly determined by three kinds of muscles. The relative amounts of red pigment pigment derivatives: also myoglobin, oxymyoglobin, and myoglobin can be preserved (Chen Mingzao, 1991). When the meat is cut into contact with oxygen, the original dark purple form of reduced myoglobin binds with oxygen and becomes a bright red oxygenated myoglobin. If the oxygen is exposed to a long time and an irreversible chemical oxidation occurs, a brownish color is formed. Myoglobin (see Figure 1 for details).

Due to lack of oxygen in vacuum packaging, most of the myoglobin (Mb) in fresh meat remains in the reduced state. The changes in myoglobin on the fresh meat surface are shown in Figure 2. Oxygenated myoglobin formed after exposure to oxygen (Mb (h) After packaging, because the oxygen in the package is consumed less, it is reduced to dark purple red reduced myoglobin (Mb), and rarely brown mutated myoglobin (MteMb), but it does not affect the whole. In flesh, the flesh color in the package is still mainly red, and the higher the vacuum is, the longer the retention of reduced myoglobin (Mb) (Seide-maneta1.1976a) has a longer shelf life. The contact can quickly combine with oxygen to present a bright red oxymyoglobin (Bloom), which is conducive to retail display.

4 rancid

Primarily from fat oxidation, odors and yellowing will occur. When the fat's own oxidation occurs, the fatty acid molecules are oxidized and decomposed into lower molecular weight aldehydes, acids and ketones, forming a source of rancid odor, vacuum packaging can The main factor that causes rancidity (oxygen) is isolated from fat, which in turn reduces the chances of reducing rancidity.

5 enzymes

Proteolytic enzymes cleave proteins into smaller molecules and also mature and tenderize at the same time. However, if they are overproduced, they will produce bad results of depravity and odor. The low-temperature preservation and vacuum packaging can achieve moderate control effects. Helps inhibit microbial growth and reproduction during maturation.

With perfect hygienic operation and temperature control, the vacuum shrinkage packaging method enables fresh meat to be stored for a month after slaughter, allowing fresh meat to ripen and tenderize for a sufficient period of time before being rotted, giving a better taste. And flavor, this is the effect that the traditional hot meat and frozen meat can't reach. At present, this vacuum shrinkage packaging method is not common in Asia, but based on the consideration of economy, convenience and quality, it will be a development trend and trend.

Reprinted from: The First Food