Foreign Material on Produce


A large wholesaler of fruit and produce discovered that the quality of their products and processing operations had been suddenly affected by a dusty foreign material. The dust had followed a remodeling project at a neighboring business.

Unknown dust on food analyzed by light and electron microscopy


Using stereomicroscopy, MVA Scientific Consultants analyzed dust samples from several locations in the facility, all of which appeared to be the same. Polarized light microscopy (PLM) and scanning electron microscopy (SEM) revealed that the dust samples contained paper fibers, starch, fiberglass and cement particles. Trace amounts of soil-derived minerals, rust, iron shavings, copper and lead chromate-pigmented paint fragments were also observed. The presence of soil-derived minerals was attributed to background dust. Starch was identified as present from the food processing operations.

However, much of the dust (i.e. cement, fiberglass, iron rust, paint, etc.) was the result of construction activities. The paper fibers that were found were from recycling and paper handling operations (such as wrapping, boxing, etc.), which were located next door.


Through the efforts of MVA Scientific Consultants, the wholesaler was able to identify the dust’s main source as the neighboring recycling operation and could respond accordingly.