Food Safety Magazine, October/November 2011

3. Presence of Natural Toxins

Natural toxins are chemicals produced by living organisms. The most common examples include mycotoxins, which are produced by mold contamination of certain commodities that include cereals, nuts, fruit and dried fruit, cocoa, spices, oilseeds and milk. Commonly known mycotoxins include aflatoxins, ochratoxin A, ergot alkaloids, fumon-isins, patulin, tricothecenes and zear-alenone. Other natural toxins include phycotoxins or toxins naturally occurring in fish and seafood, for example, domoic acid, ciguatera toxins and paralytic shellfish toxins. Finally, certain plants can produce compounds that are toxic to humans. Examples of plant toxins include glycoalkaloids and cyanide in bitter apricot kernels.

“...we must be aware of potential contamination
incidents and sources of contamination that
may affect the safety and quality of our

products.”

4. Accidental Contamination at a “Point Source”

This type of contamination may occur during the production, preparation and packaging of foods. Typically, this type of contamination occurs during the production of raw food commodities, in the way they are grown (fertilizers and pesticides used during agricultural production) or, in the case of animal products, how they are raised or produced (veterinary drugs such as antibiotics and hormones).

removed during processing. Thus, avoiding them at the source is essential to ensure the safety of processed products. Regardless, regulatory bodies have established maximum levels for many contaminants, so it is important to know these levels and generate proper specifications for raw materials. In cases where there is no regulatory reference, consider the nature and source of the material to ensure that you have as much information as possible. If analysis is needed, then several considerations must be taken into account.

5. Intentional Contamination

This type of contamination is perhaps the most difficult to handle since adulteration is unexpected and difficult to anticipate. Adulterants may be used to sell lower-value products as the original product, mask products that are already past their prime or add a cheaper compound to a food or ingredient and sell it for a higher value. Recent examples include the use of Sudan red in spices, melamine in milk and the use of inedible Japanese star anise (which contains sikimitoxin) instead of the closely related edible and innocuous Chinese star anise.

So how can a company protect itself from this wide array of chemicals?

First, it is important to follow the usual due diligence and work with trustworthy suppliers. The usual prevention programs are essential since, in most cases, chemical contaminants cannot be

Importance of Sampling and
Sample Preparation

Sampling and sample preparation are crucial operations in the analytical determination of chemical contaminants. Proper sampling will give reliable analytical results representative of the whole lot. When the food matrix or the potential contaminants are homogeneously distributed (e.g., antibiotics in milk), sampling is much easier, and only proper sampling and handling techniques are required. However, if the contaminant is not homogeneously distributed (e.g., aflatoxin in grains or peanuts), then it is important to follow sampling procedures that will yield the most representative results possible. Usually, when sampling is challenging, regulatory bodies provide guidance on proper methods. If a third-party laboratory is hired, it will usually provide you with the best sampling protocol and procedures to submit samples.

When unknown chemical contamina-
tion is suspected, then laboratories usu-
ally ask for a precise description of the
taste and smell (if available) of the sus-
pected food or beverage to provide use-
ful clues to the identity of the
contaminant. Likewise, if illness or in-
jury has already occurred, then a full de-
scription of the onset time, symptoms
and any medical diagnosis can also pro-
vide important information to determine
the appropriate analytical procedure.

Contaminant Analysis

Once samples are obtained, then selection of an extraction and analytical method will help you get proper information. If the compound is a known food contaminant, then an analytical method will likely be available and can be used to analyze the suspect sample. If this is the case, it is important to note whether the method is validated for the particular food matrix in question and whether the limit of detection will provide information that is appropriate to make an informed decision.

When contaminants are unexpected, then the very first step will likely be to develop a new method. This involves a thorough literature search of the “ unknown” compound to narrow down a method suitable for extracting the contaminant from the particular food matrix and quantifying it with sufficient certainty to make appropriate decisions.