Traditional Tupperware containers are made from a type of plastic called polypropylene, which is known for its durability, flexibility, and resistance to high temperatures. However, there are a few reasons why it's not always recommended to put new Tupperware in the dishwasher:
Temperature and agitation: Dishwashers use high temperatures and powerful jets of water to clean dishes. While polypropylene is generally heat-resistant, exposing new Tupperware to the high temperatures and agitation in the dishwasher may cause the plastic to warp or deform slightly, especially if the dishwasher has a high-temperature setting.
Detergents and chemicals: Dishwashing detergents and rinse aids used in dishwashers may contain harsh chemicals that can potentially affect the surface of new Tupperware containers. This might lead to discoloration, clouding, or even leaching of chemicals into the food stored in the containers.
Longevity and appearance: Handwashing Tupperware can help preserve its appearance and extend its lifespan. Washing Tupperware by hand with mild soap and warm water is gentler on the plastic and less likely to cause any damage.
Labels and printing: Some Tupperware containers have labels or printing on the exterior. The dishwasher's heat and agitation could potentially fade or damage these markings over time.
Avoiding risks: While Tupperware containers are generally safe for food storage, some people prefer to handwash new containers to be extra cautious and avoid any potential risks associated with dishwasher use.
That said, many Tupperware containers are labeled as dishwasher-safe. If you have older Tupperware that has been through the dishwasher without any issues, it is likely safe to continue doing so. However, to be certain about the care instructions for your specific Tupperware products, always check the packaging or the manufacturer's recommendations.
For older Tupperware containers or those without clear labeling, handwashing is the safest option to maintain the longevity and appearance of the containers. Wash them with mild soap and warm water, and avoid using abrasive scrubbers or harsh chemicals. Additionally, avoid using Tupperware containers in the microwave unless they are specifically labeled as microwave-safe.