Case Study: Filth Analysis in Granola Bar

Filth analysis is an essential tool in mitigating the problem caused by foreign material in a food product; equipment damage, delays in supply chains, disputes with vendors, and consumer injuries.

The technical and regulatory experts in filth and extraneous materials at the Food and Drug Administration (FDA) determine the maximum levels of defect in human foods. The criteria is based on the reported findings (type, size and distribution) and information of how the product is grown, harvested, and processed.

Although the FDA does allow for some extraneous materials in food products, companies should aim for a higher level of quality by performing filth analysis, locating the source of the filth and mitigating the issues.

THE PROBLEM:

A food company received a complaint from a customer of filth, possibly insect parts, in their chocolate chip granola bar. A portion of the suspicious bar was sent to MVA Scientific Consultants with a request that we determine if insect parts were indeed present in the bar.

THE ANALYSES:

The partial granola bar was examined using optical microscopy.

We used a combination of bright-field reflected light microscopy (Figures 1 and 2) and transmitted polarized light microscopy (PLM) (Figures 3 and 4).

Figure 1. Bright-field reflected light image of suspicious particle.

Figure 2. Bright-field reflected light image of second suspicious particle.

Figure 3. Transmitted light image of suspicious particle.

Figure 4. Same image as in Figure 3 with crossed polarizers.

THE OUTCOME:

Examination of the granola bar revealed two areas at the open end of the wrapper that appeared to have dark, elongated structures resembling a non-food product. PLM analysis of sections from those areas revealed that each was composed of cellulose (plant material) with a structure consistent with cereal grain husk. No insects or insect parts were observed on the granola bar.