Beware! The health minefield of reusing plastic bottles: Different materials make a huge difference—absolutely avoid these behaviors!

Preface 

Mineral water bottles, beverage bottles, oil jugs …… Plastic bottles are essential containers in every household. Many people are accustomed to reusing empty bottles—to store oil, vinegar, brew tea, or hold hot water. But you might not know that... Not all plastic bottles can be reused. Improper recycling methods may cause harmful substances from plastics to migrate into food, posing hidden health risks. 

The safety of plastic bottles hinges on the bottom. “ Digital identification ” The corresponding material. Different materials exhibit vastly different heat resistance and stability, and are suited to entirely different application scenarios. For professionals in the film industry, understanding the material properties of plastic bottles is an essential extension of their knowledge about food-contact films. For ordinary consumers, distinguishing between material types and avoiding common pitfalls is key to safeguarding food safety. This article dissects the characteristics of various plastic bottle materials, highlights unhealthy practices associated with repeated use, and teaches you how to use plastic bottles scientifically and appropriately. 

1. First, take a good look at the bottom of the plastic bottle: “ Digital password ” , corresponding to different materials 

The number inside the triangular recycling symbol on the bottom of a plastic bottle. 1-7 Representing different resin materials, their performance and application scenarios vary dramatically—this is the key basis for determining whether they can be reused. The most common ones encountered in daily life are as follows: 5 Species: 

1. Digital 1： PET (Polyethylene terephthalate) 

• Features: High transparency, lightweight and inexpensive, with heat resistance. ≤70℃ 
• Common uses: mineral water bottles, cola bottles, juice bottles 
• Reuse prompt: It is not recommended to refill water or food containers repeatedly. Especially, do not fill it with hot water. 

2. Digital 2： HDPE (High-density polyethylene) 

• Features: High toughness, acid and alkali resistance, and heat resistance temperature. ≤110℃ 
• Common uses: milk bottles, laundry detergent bottles, cooking oil containers 
• Reuse prompt: Can be reused for short periods. However, it must be thoroughly cleaned to prevent residual buildup that could breed bacteria. 

3. Digital 3： PVC (Polyvinyl chloride) 

• Features: low cost, high hardness, and heat resistance temperature. ≤60℃ 
• Common uses: cling film, some low-quality beverage bottles, chemical containers 
• Reuse prompt: Repacking food is strictly prohibited. High temperatures or contact with oils can release harmful substances such as plasticizers. 

4. Digital 4： LDPE (Low-density polyethylene) 

• Features: Good flexibility, low-temperature resistance, and high-temperature resistance. ≤80℃ 
• Common uses: supermarket shopping bags, yogurt bottle sealing films, and certain flexible bottles. 
• Reuse prompt: Reusable, but avoid filling with high-temperature liquids. 

5. Digital 5： PP (Polypropylene) 

• Features: Excellent heat resistance and high chemical stability; the maximum heat-resistant temperature can reach... 130℃ 
• Common uses: microwave meal containers, certain sports water bottles, baby bottles 
• Reuse prompt: Suitable for reuse , it’s in a plastic bottle. “ Safety Top Student ”

II. Key Alert: Avoid reusing plastic bottles—this... 5 The most unhealthy behavior 

Many people think that “ Just wash it clean and you can use it. ” However, the following behaviors directly accelerate plastic degradation and release harmful substances—truly a minefield for your health. 

(1) Use PET Bottle (number 1 ) Fill with hot water, brew tea 

This is the most common erroneous behavior. PET The material has poor heat resistance and exceeds... 70℃ They will soften and deform, and may simultaneously release trace amounts of plasticizers and antimony. When hot water or tea is stored for extended periods in mineral water bottles or cola bottles, high temperatures can accelerate the migration of harmful substances; in particular, the acidity of tea can further intensify this process. 

(2) Using plastic bottles to store oil, vinegar, and soy sauce over the long term. 

Oil, vinegar, and soy sauce are classified as oils or acidic liquids, which can erode the molecular structure of plastic bottles. 

• Ordinary PET After coming into contact with oils and fats, bottles tend to leach harmful substances. 
• Even HDPE Bottles that have been used for long-term oil storage can harbor aflatoxins due to residual oils. The risk is even higher if they aren't thoroughly cleaned. 
• Acidic vinegar and soy sauce can accelerate the aging of plastics, causing bottle bodies to become brittle and crack, while also releasing plasticizers. 

(3) Use PVC Bottle (number 3 ) Store any food. 

PVC The material itself contains vinyl chloride monomer, and plasticizers are added during the manufacturing process. These substances can migrate into food when exposed to heat, oil, or acid; long-term consumption can damage the liver and kidneys. 

(4) Plastic bottles are reused directly without being cleaned first. 

Plastic bottles that have previously contained beverages or milk may still have residual sugars and proteins inside. These substances provide an ideal environment for bacterial growth. “ Nursery bed ”。

• If you fill the bottle with water directly without cleaning it first, bacteria will multiply rapidly inside the bottle, potentially causing gastrointestinal discomfort if you drink from it. 
• Using steel wool brushes or boiling with high-temperature water during cleaning can scratch the bottle’s surface, accelerate plastic degradation, and paradoxically increase the risk of releasing harmful substances. 

(5) Storing food long-term in used plastic bottles 

Many people use large-capacity plastic bottles as storage containers for rice, beans, flour, and other dry goods. However, used plastic bottles have poor sealing performance, making them prone to moisture and mold. They can also absorb dust and bacteria from the air. 

• When the bottle is exposed to sunlight for extended periods, ultraviolet rays will accelerate the degradation of the plastic, releasing more harmful substances. 
• Some recycled plastic bottles may be made from non-food-grade materials that already contain pollutants such as heavy metals. 

III. Scientific Guidance: The Right Way to Reuse Plastic Bottles Method 

Not all plastic bottles are unsuitable for reuse. By following the methods below, you can use them safely: 

1. Priority selection “ Digital 5 inches of the PP Bottle 

PP The material is the only type of plastic that’s safe to heat in the microwave; it boasts excellent heat resistance and stability. Use it! PP Bottles are safest when refilled with water or room-temperature food. 

2. Use repeatedly for short periods, and replace promptly. 

Even PP Bottle or HDPE Bottles are also not recommended for long-term use. It is advised that they be reused no more than... 3 Next, if you notice that the bottle has become brittle, turned yellow, or has an odd odor, discard it immediately. 

3. Clean properly, handle gently. 

When cleaning plastic bottles, use warm water mixed with dish soap and scrub gently with a sponge or soft cloth. Avoid using steel wool or hard-bristled brushes, as they can scratch the bottle’s surface. After washing, let the bottles air dry—do not expose them to direct sunlight. 

4. Specify the purpose and use them categorically. 

• For hot water and tea brewing, glass or ceramic cups are preferred. 
• For oil and vinegar, use glass bottles or food-grade stainless steel containers. 
• When you go out to drink water, choose a dedicated sports water bottle—don't use a beverage bottle as a temporary substitute. 

5. Beware “ Three Nothings ” Plastic bottle 

When buying plastic bottles, choose those that have... “ For food contact ” Products with clear material specifications and markings. Avoid purchasing low-quality plastic bottles with unclear labels or a pungent odor. 

IV. Extended Knowledge: Plastic Bottles and Food Packaging from the Perspective of the Membrane Industry 

From the perspective of membrane materials, the material used for plastic bottles is derived from the same source as that used for food-grade packaging films. 

• PET Not only can it be used to make beverage bottles, but it’s also a common raw material for high-end food packaging films. Its high transparency makes it ideal for packaging snacks and cooked foods. 
• HDPE Its corrosion resistance makes it an ideal material for laundry detergent bottles and food packaging films. 
• PP The material’s heat resistance makes it widely used in microwave food containers and steam-cooking films. 

When producing films for food contact, membrane manufacturers strictly adhere to... GB 4806.7-2016 Standards dictate the controlled addition of additives to ensure the safety of film materials. This also serves as a reminder to consumers that, whether it’s plastic bottles or food packaging films, “ Food-grade ” Both labeling and material certification are indispensable. 

Conclusion 

The key to reusing plastic bottles lies in... “ Choose the right material for the right setting. ” A tiny digital identifier hides a profound truth about health. PET Although the bottle is lightweight, it’s not suitable for holding hot water. PP Although the bottle is safe, it cannot be used for long-term storage of oils. 

For professionals in the membrane industry, understanding the properties of plastic materials can help them better grasp the demands of downstream food packaging. For ordinary consumers, only by avoiding unhealthy usage practices and choosing the right containers can they truly achieve... “ Use with confidence ”。

Reducing plastic pollution isn't about eliminating reuse altogether—it's about reusing plastics scientifically. Let’s start by clearly understanding the nature of plastic bottles. “ Digital password ” Start by safeguarding your own health and that of your family.