Science & Research

Volume IV - 4.1 Introduction

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Orientation and Training
Food and Drug Administration

Section 4 - Microanalytical and Filth Analysis

The Food, Drug, and Cosmetic Act protects the public from the presence of filth, putrid or decomposed material in food products, and those products that may have been exposed to insanitary conditions that may contaminate the product with filth or render it injurious to health. The terms filth, foreign material, or extraneous material are used interchangeably. The courts define filth in a common sense manner; filth does not have any specialized or technical definition. Filth is any type of matter that obviously does not belong in a food product. Representative examples of filth in food products include but are not limited to rodent excreta, insects, parasites, and extraneous materials such as metal and glass shards.

Filth can enter a product through many forms and sources; and is often invisible to the consumer. Filth may be present in food naturally and unavoidably, or as the result of an intentional or unintentional controlled bad practice. The identification, confirmation and quantitation of the filth can help determine how the material was found in the product, if it was a natural and unavoidable event, an accidental event, a controllable event, an unintentional event and/or a deliberate intentional event.

More importantly, analysts can assess the real or potential health risk involved with these adulterants. Given today’s food production operations and storage facilities, when the presence of a health hazard or vector potential is confirmed, the findings may place added emphasis on certain problems and the surrounding circumstances. The objectives of this chapter are to introduce the visual, macro and microscopic techniques, practices, and procedures used to identify and confirm the presence of adulterants in various commodities, and provide practice in reporting such findings in a clear and concise manner.

Given the nature of the work and the broad definition of filth, analysts with a strong background in the biological/agricultural sciences with special emphasis in entomology, pest control, agricultural and food production have an advantage in this course work. However, FDA filth analysts come from diverse disciplines. This chapter is not intended to be all inclusive, but will provide FDA analysts the basic six to nine month orientation program for beginner filth analyses.

4.1.1 Reference Books and Materials

The trainer provides, as a minimum, the following instructional materials for the trainee's general use:

  • Gorham, J. R. (Ed.). (1991). Ecology and management of food-industry pests [Formerly released as FDA Technical Bulletin No. 4]. Gaithersburg, MD: AOAC International.
  • Vail, D. J. (n.d.). Micro-analytical biology workbook for food sanitation control analysts (out of print, Vol. 1). Atlanta, GA: FDA, Southeast Regional Laboratory.
  • AOAC official methods of analysis (current Edition). Gaithersburg, MD: AOAC International.
  • U.S. Food & Drug Administration, Center for Food Safety and Applied Nutrition. (1998). Macroanalytical procedures manual (FDA Technical Bulletin No. 5). Retrieve 1998 electronic version from [Originally released in print by FDA in 1984 by Olsen, A. R. (Ed.), Knight, S. A. (Tech. Ed.), Ziobro, G. C., Ph.D. (Assoc. Ed.)]
  • Harris and Reynolds (Eds.) Microscopic-analytical methods in food and drug control (out of print, FDA Technical Bulletin No. 1).
  • Gorham, J. R. (Ed.) (1981). Principles of food analysis for filth, decomposition and foreign matter ( FDA Technical Bulletin No. 1, 2nd Ed.). Gaithersburg, MD: AOAC International.
  • Gorham, J. R. (Ed.). (1978). Training manual for analytical entomology in the food industry (out of print, FDA Technical Bulletin No. 2, HHS Publication No. (FDA) 77-2086).
  • Gentry, J. W., Harris, K., Gentry, Jr., J. W. (1991). Microanalytical entomology for food sanitation control (Vols. I and II, revised reprint of O.D. Kurtz and K.L. Harris AOAC publication by the same name). Gaithersburg, MD: AOAC International.
  • Olsen, A. R., Sidebottom, T. H. and Knight, S. A. (1996). Fundamentals of microanalytical entomology, a practical guide to detecting and identifying filth in foods. Boca Raton, FL: CRC Press.
  • Hui, Y. H., Bruinsma, B. L., Gorham, J. R., Nip, W., Tong, P. S., Ventresca, P. (2002). Food plant sanitation. New York: Marcel Dekker, Inc.

4.1.2 Sample Collections

The trainer arranges for the collection of these 20 food samples for Section 4.4 training assignments:

  • Wheat or other whole grain (Section 4.4.2)
  • Green coffee beans or cocoa beans (Section 4.4.2)
  • Flour (Collect enough to satisfy Section 4.4.2 and
  • Whole or crude spice (Section 4.4.2)
  • Whole figs or dates (Section 4.4.2)
  • Shell nuts (Canned/Mixed) (Section 4.4.2)
  • Blueberries, raspberries or cherries (Fresh/Frozen) (Section 4.4.2)
  • Fig paste or other fruit paste (Section
  • Chocolate (Section
  • High bran content bakery goods (Section
  • Dried ground spice (Collect enough to satisfy Section, and
  • Peanut butter (Section
  • Canned tomato juice (Collect enough to satisfy Section and
  • Canned sliced button mushroom or dried wild mushroom (Section
  • Whole fruit or vegetable (Canned or Fresh) (Section
  • Cinnamon or Cassia sticks (Section
  • Tomato concentrate product (puree, sauce or paste) (Section
  • Berry or citrus juice product (Section
  • Rodent, insect, floor sweepings, exhibits (Section 4.4.5 and 4.5.1)
  • Rodent contaminated food and packaging (Section 4.4.5 and 4.5.1)

4.1.3 Investigations Training

The trainer makes arrangements for the trainee to accompany a district investigator on the following types of inspections:

  • Establishment Inspection (EI) of a food processing plant and a food warehouse.
  • Wharf examination of import foods.

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