toxin detection techniques

-Physicochemical Methods
In this method, the mycotoxin is extracted, purified, concentrated and separated via thin-layer chromatography before the mycotoxin in the food sample can be quantified.

-Immuno Assays
Mycotoxins are made to interact with specific antibodies before they are isolated. Radioimmunoassay (RIA) and enzyme-linked immunoabsorbent assay (ELISA) are two techniques of this method.

-Biological Assays
Biological systems such as cell and tissue cultures, animals and microorganisms are used as bioassays to detect and quantify mycotoxins. Furthermore, it can display the physiological and pathological effects of mycotoxins.

Adapted from: Food and Beverage Mycology, 2nd Edition, Larry R. Beuchat, 1987

Mycotoxins

The harmful chemicals produced by fungi in food are referred to as mycotoxins. Mycotoxins do not get eliminated during digestion or even temperature treatments during food processing. These harmful compounds can be carcinogenic, teratogenic, tremorgenic, hemorrhagic and dermatitic. They may also limit growth in affected consumers as protein synthesis is inhibited.

Adapted from: http://en.wikipedia.org/wiki/Mycotoxin and
Food and Beverage Mycology, 2nd Edition, Larry R. Beuchat, 1987

Isolation and Identification of Foodborne Pathogens

Conventionally, the sample food is mixed with a buffer and homogenized before it is placed into a non-selective media for the resuscitation of the microorganisms. Upon revival of the microorganisms, the food sample is incubated in a selective media for selection of specific microorganisms. Then it is placed in a growth media which promotes propagation of the microorganism. The microorganisms go through another selection phase via the use of differential and selective agars. After a specified incubation period, the colonies present on the agar will be isolated. These isolates then undergo biochemical testing for identification and characterization purposes. Cultural methods are labour intensive and time-consuming. Hence, rapid methods have been established to give accurate results, quicker.

Rapid methods include
-Immunological Methods (Antibody-based Assays)
-DNA/RNA Methodology (Nucleic Acid-based Assays)
-Next Generation Technologies
-rTPCR
-Immunosensors/ Biosensors
-DNA Microarrays

Adapted from: Food Microbiology, M.R. Adams & M.O. Moss, 1995