By Richard Haynos
“Waiter! There’s a Fly in
and So Much More
Many people have found a fly in their soup. However, what few realize is that here is so much more in the bowl and
on the dinner plate.
There are grain insect fragments in
pasta. Tomatoes used to make soup
have rot fragments. Broccoli is loaded with thrips, aphids and their
body parts. Rice can be crawling with Indian meal moth caterpillars.
Allergenic mites cling on fish. Even seasonings used to flavor food can
contain cigarette beetle larva, scale insects and pieces of rodent feces.
In 1938, the Federal Food, Drug and
Cosmetic Act replaced earlier federal
statutes. This landmark legislation defined two types of adulteration that relate to microanalytical entomology:
Section 402 (a) ( 3) states that a food
shall be deemed to be adulterated if it
consists in whole or in part of any filthy,
putrid or decomposed substance, or if it
is otherwise unfit for food; Section 402
(a) ( 4) states that it is adulterated if it has
been prepared, packaged or held under
insanitary conditions whereby it may
have become contaminated with filth,
or whereby it may have been rendered
injurious to health.
This legislation increased the emphasis on detection and prevention of pest-related insanitation by encouraging
inspections of food processing, packing
and storage establishments for pest infestations and by increasing the need for
more sophisticated levels of entomological identification. Microanalytical entomology emerged as a distinct scientific
discipline shortly after the enactment of
this legislation. In practice, it is the
forensic scientific examination of foods,
drugs and cosmetics for contamination
with filth from insects or other pests and
the detection of filthy conditions involving these pests in factories, warehouses and other places where these
products are manufactured, processed,
packed or stored.
The presence of these pests, their body parts or their excrement in food is repugnant to most and may be a health hazard, but human foods are attractive to a wide
variety of animals, as competition for nutritive substances is keen and continuous,
and food pests take advantage of every opportunity to convert human food to their
own use. All edible portions of field and orchard crops are affected by an assortment of pests. After the crop is harvested and started through some sort of processing, it encounters two classes of pests: those associated mainly with the food itself
and those associated with buildings.
The scientific discipline concerned with the isolation, detection and identification of these “filth elements” is microanalytical entomology.
A Little History
The U.S. Pure Food and Drug Act of 1906 marks the beginning of the development of microanalytical entomology. During this era, food adulterants were studied by the same analysts who performed the microchemical testing of drugs as well
as other analyses that required the use of a microscope. This discipline grew out of
the need for some microscopists to specialize in examinations for animal and
Challenges to Analyses
Any laboratory specializing in this
field faces several challenges when presented with a product for filth analysis.
The first challenge is deciding whether
to do a macroscopic or a microscopic
procedure. A macroscopic analysis is
chosen if the product is unprocessed
and whole and if the filth elements present in the product are visible to the
naked eye. These filth elements include
live or dead insects, rodent pellets, dung,
bird droppings and insect excreta. A microscopic analysis is chosen if the product is further processed and the filth
elements are small and obscured by the
product. These filth elements include