Analyst Blog

Scientists in Spain used an array of 16 chromogenic indicators with different chemical recognition properties to follow the ageing of chicken stored in modified atmosphere packaging (MAP).

Many currently available methods to check meat spoilage are destructive, time-consuming, expensive and require qualified personnel. This means that they are fine for food safety inspections, but not suitable for use in shops or on every piece of packaged meat. Chromogenic sensors are cheap, versatile, can be printed on packaging and easily measured by cameras or the naked eye. The team observed characteristic colour fingerprints for each day of the study (which was carried out over 12 days) and gave clear differentiation at two-day intervals.

Once the 16-dye array had been successfully used, the team developed a simpler version based on just two dyes with three categories allowing differentiation between ‘fresh’, ‘beginning of decay’ and ‘non-fresh’. This shortened version could be printed on packaging and observed by the naked eye.

Monitoring of chicken meat freshness by means of a colorimetric sensor array
Analyst, 2012,
DOI: 10.1039/C2AN35211G

Monitoring volatile organic compound (VOC) levels in workers exposed to these compounds is important for their health. This is normally done by taking blood samples. However, scientists are looking towards using saliva samples instead, as a non-invasive technique.

Collecting saliva samples is done by either passive drool (in which the subject has to sit tight while their saliva drips off their lips into a collection vessel) or by chewing on a piece of cotton wool (which is then centrifuged to collect the saliva). But, neither technique can be used to detect VOCs in saliva.

Now, UK scientists at Loughborough University and Unilever R&D in the Wirral have come up with a new approach to overcome this problem. They carried out sampling of VOCs directly in the mouth using a polydimethylsiloxane sampler.

Although it takes 10 minutes to collect a sample, the team says that they are working towards reducing the time to one minute. The method could be combined with other VOC sampling methods – breath and skin analysis – they say.

Sampling and Characterisation of Volatile Organic Compound Profiles in Human Saliva Using a Polydimethylsiloxane Coupon Placed Within the Oral Cavity
Analyst, 2012, Accepted Manuscript
DOI: 10.1039/C2AN35432B