A new bottle smells of plastic: where the smell comes from and how to trace it
A smell complaint is hard to argue with and easy to mishandle. The first job is not to fix it but to find out which part is actually causing it.
Start by finding the part
A bottle is usually several components: body, lid, seal, sometimes a straw or an infuser. They are often made from different materials, sometimes by different suppliers. 'The bottle smells' is rarely true of all of them.
Separate the parts and smell each one on its own. In our experience that single step answers most smell complaints.
The four usual sources
- The body resin or colourant. Some materials and some colours carry more odour than others, and it can vary between material batches.
- The silicone seal. Seals are a common source of smell, and the smell can be absorbed into the water even when the body is neutral.
- The packaging. A product sealed in a bag straight after production can trap odour from the plastic, the ink on the box or the carton itself, and release it when the customer opens it.
- Production residue. Traces left from the moulding or assembly process on surfaces that were not cleaned before packing.
Each source has a different fix, which is why guessing is expensive.
How a buyer can check a sample
You do not need a laboratory to narrow it down:
- Open the pack and smell it straight away, then again after the parts have been out of the bag for a while. If the smell fades, packaging or trapped odour is the likely source.
- Take the parts apart and smell each one separately.
- Wash the parts in warm water with a mild detergent, rinse, and fill the bottle with hot water as a user would. Then taste and smell the water.
- Compare with a second sample from a different carton or batch.
Write down what you found and send it with photos of the parts. It turns a complaint into something a factory can act on.
What the factory should do with the answer
- If it is the seal: ask for the seal material and grade, and whether an alternative seal is available.
- If it is the body: check the resin batch and the colourant for that lot against an earlier good lot.
- If it is the packaging: review how soon after production the parts are bagged, and the materials of the bag and box.
- If it is residue: add or improve a cleaning step before packing.
How long an odour takes to fade, and whether a given process change removes it, depends on the product and materials. Those answers should come from testing the actual product, not from a general rule.
Smell and safety are separate questions
A smell is a quality problem and a customer-experience problem. It is not, on its own, proof that a product is unsafe — and the absence of a smell is not proof that it is safe.
Safety is shown by food-contact test reports for your market. If a smell complaint makes your customer ask about safety, answer with the reports, and handle the smell as the separate quality issue it is. For which reports each market expects, see our food-contact compliance article.