Which plastics is most appropriate for the packaging of fresh red meat?

For the packaging of fresh red meat, polyvinyl chloride (PVC) is a commonly used plastic that is quite appropriate, and here's why:

1. Oxygen permeability

- Fresh red meat needs a certain amount of oxygen to maintain its bright red color. PVC has a relatively controlled oxygen permeability. The presence of a small amount of oxygen helps in keeping the myoglobin in the meat in its oxygenated form (oxymyoglobin), which gives the meat its appealing red color. If the packaging material is completely impermeable to oxygen, the meat can turn a purplish - red or brown color due to the conversion of oxymyoglobin to metmyoglobin.

2. Moisture resistance

- PVC is effective in preventing the loss of moisture from the meat. If the meat loses too much moisture, it can lead to a phenomenon called "drip loss," where the juiciness of the meat is compromised. At the same time, it also prevents the entry of external moisture, which could otherwise lead to spoilage and the growth of microorganisms.

3. Clarity and visibility

- PVC is transparent, allowing consumers to clearly see the quality and appearance of the meat. This is an important factor in the marketing of fresh red meat products, as consumers can visually inspect the color, texture, and any possible defects of the meat before making a purchase.

4. Sealability

- It can be easily sealed to create a hermetic environment. A good seal helps to maintain the internal gas composition (including the appropriate level of oxygen) and keep the meat fresh for a longer period.

However, other plastics like polyethylene (PE) can also be used in combination with PVC or in certain modified forms. PE provides good flexibility and toughness, which can be beneficial for packaging that needs to withstand some mechanical stress during handling and transportation. But in terms of the overall requirements for fresh red meat packaging such as color maintenance, moisture control and visibility, PVC is often a more preferred choice among common plastics.

It's also important to note that with increasing concerns about the environment and health, there is a trend towards more sustainable and safe packaging materials. Some biodegradable plastics and those with lower potential for chemical migration are being explored as alternatives for meat packaging.