Detect antibiotics in real time.

The health of consumers is adversely affected by the presence of harmful chemicals in food, such as antibiotics. Pesticide and veterinary drug residues are a serious concern. Many countries have set maximum limits for chemical residues in food, which are enforced by regulatory agencies that use a variety of detection methods.

However, many current detection techniques are often too time-consuming, expensive and labor-intensive. Minimizing the time, effort and cost, and improving the quality of these analyses, would provide a significant benefit to governments, industry, academic scientists and consumers. New analytical methods are needed to expand the range of veterinary drug and pesticide analytes that can be detected in animal- and plant-derived food products more efficiently.

Toward this end, European scientists are developing simple on-line sensors that can be used to detect antibiotics in animal foods, dairy products and meat. These sensors will reduce analysis times and laboratory analysis costs.

Researchers already have developed a portable prototype that can be used to detect antibiotics in milk. The instrument includes a sampling unit, a microreactor and an optical cell. The molecular recognition of the analyte--the antibiotic--is accomplished by using molecularly imprinted polymers (MIPs). These recognition elements selectively bind the analyte. The detection methodology is based on fluorescence.

Molecular imprinting is a chemical technique used to make molecule-specific cavities that mimic the behavior of natural receptor binding sites that do not have the temperature sensitivity of the natural systems. Artificial polymers can be built for any target molecule. The polymers are prepared in the presence of a template molecule, such as an antibiotic, that interacts with the polymer network via ionic, covalent or hydrogen bonding interactions.

After polymerization, the template is removed, and the polymer exhibits the ability to recognize the template with a high degree of selectivity. What are left are recognition sites complementary to the antibiotic in the position and shape of the functional groups. The polymer is subsequently able to selectively rebind the antibiotic.

The participants in this E.U.-funded research project did not achieve a specificity and detection limit that exactly met their objective. However, the researchers believe that making minor optimizations should strongly improve the performance of these sensors.

A Flair-Flow Europe report on the development of new sensors for food quality and safety analysis has been published. The report may be downloaded from http://www.flair-flow.com/industry-docs/sme-syn4.zip.

Further information. Maria Kempe, Lund University, Department of Cell and Molecular Biology, Biomedical Center, B12, SE-221 84 Lund, Sweden; phone: [phone]; fax: [phone]; email: [e-mail].