Clumping defect is a frozen-product fault in which individual pieces adhere into lumps, caused by slow freezing, partial thawing or temperature fluctuations, and it signals cold-chain failures that affect portionability and buyer acceptance.
In trade practice
Buyers check incoming IQF shipments by squeezing bags or shaking cartons to detect lumps; significant clumping is grounds for rejection or price dispute. The root cause is usually a temperature excursion during storage or transport, so temperature logger data is the first document requested when clumping is found. Suppliers can reduce risk by ensuring product is fully frozen before packing and by maintaining a stable cold chain throughout transit.
In a specification
Purchase contracts for IQF product typically include a clumping clause stating that product must be free-flowing, with any tolerance for minor surface adhesion defined as an indicative maximum percentage by weight.