Can you thaw meat in plastic wrap?

It is generally not recommended to thaw meat in its original plastic wrap at room temperature.

When meat thaws at room temperature, it enters what is known as the "danger zone" (between 40°F and 140°F or 4.4°C and 60°C). Bacteria multiply rapidly in this temperature range. If you leave the meat in plastic wrap while thawing at room temperature, any bacteria that may be on the surface of the meat will proliferate.

If you plan to use a microwave to thaw meat quickly, in most cases the plastic wrap that came with the meat is not appropriate. Heating plastic in a microwave can cause it to melt or release harmful chemicals into the food.

Safer thawing methods

If you want to thaw meat in the refrigerator, you can place it in plastic wrap. The low temperature of the refrigerator (ideally below 40°F or 4.4°C) slows the growth of bacteria. It usually takes more time to thaw meat this way. For a small piece of meat (about 1 pound or 0.45 kg), it may take a day or so to completely thaw.

Another option is to cover the meat with plastic wrap if you are thawing it under cold water. This method is faster than thawing in the refrigerator. The cold water should be kept at a temperature below 70°F (21.1°C) and make sure the water is constantly flowing and the plastic wrap is well sealed.

So while you can thaw meat in plastic wrap in the refrigerator or under cold tap water with the proper precautions.

How is plastic wrap made?

The main raw material of plastic wrap is polyethylene (PE), such as low-density polyethylene (LDPE). This raw material is usually in granular form. At the beginning of the production process, these plastic granules are transported to the hopper of the film blowing machine. These plastic granules are refined and polymerized through petrochemical processes. For example, polyethylene gas exists under high temperature, high pressure and catalysts to undergo polymerization to produce polyethylene.

In the film blowing machine, the plastic granules first enter the screw propeller. The screw rotates inside the barrel, pushing the plastic granules forward. As the plastic granules move along the barrel under the action of the screw, the heating device outside the barrel heats the plastic granules. The heating temperature is generally around 160-220℃ (the specific temperature varies depending on different plastic raw materials and product requirements), so that the plastic particles gradually form a uniform plastic melt.

When the plastic melt is ejected from the die-shaped joint of the plastic melt machine, it forms a tubular film bubble. There is an air ring above the die head, which injects air into the tubular film bubble to inflate the film bubble. The blow-up ratio is usually between 2-3 (the blow-up ratio refers to the ratio of the film bubble diameter to the die head diameter). For example, if the die head diameter is 100mm, the diameter of the blown film bubble may reach 200-300mm. At the same time, the film bubble is stretched in the process of upward traction, and the molecular chain is axial in the stretching direction, which helps to improve the strength and toughness of the film.

The film bubble that has been blown and cooled needs to be cooled quickly to fix its shape. The film blowing machine is equipped with a cooling device, usually an air cooling or water cooling system. Air cooling is to blow cold air to the surface of the film bubble through a fan, and water cooling is to contact the surface of the film bubble with water through a water ring or spray. The cooled film bubble becomes the basic form of the plastic film.

The plastic film after film blowing may also need some post-processing. For example, the film may be surface treated to improve its printing performance or increase its surface viscosity, so that the fresh-keeping film can better fit the container or food surface. At the same time, the film will be rolled into a roll. Depending on the specifications and uses, the size and length of the roll will vary, which is convenient for subsequent packaging and sales.