38 FOOD & DRINK TECHNOLOGY
that it is proven to be suitable for use in food production.
In a separate study, a digital salt meter was used to measure salt in bakery products. Te device detects and converts the conductance of a sample into sodium chloride concentration.
Steve Garrett.
Bakery products were blended with water and then filtered prior to measurement. Reference analysis was performed on the same samples using both silver nitrate titration to determine chloride content and atomic absorption spectrophotometry (AAS) to determine sodium content.
“Instrumentation has improved considerably in the past 10 years with advances in microelectronics and engineering offering analysts in-, on-, or at-line capability for measuring food quality.”
Results from analysis showed reasonable correlation with results obtained using AAS.Te measurement of sodium via chloride (using silver nitrate titration) produced much lower values. It seems that the conductivity based digital salt meter is most suited to measurements of liquid foods in laboratory conditions. For bakery products, an additional step of blending with water was required.
Julian South.
www.scientistlive.com
As the results obtained correlated with results obtained with AAS but slightly overestimated the salt content, further calibration with salt standards prepared in bakery
be used for in-line applications. Various food samples - including prawns, sausage, poultry, gravy, vegetables, soups and fillings were analysed in duplicate under standard laboratory conditions and compared with a UKAS reference method with a relevant pH meter with appropriate glass electrode. Results from the laboratory analysis on the range of food products tested showed good correlation with the results obtained by the traditional method.
Te ISFET pH probe was also trialled in a poultry factory and it became apparent that the environmental conditions and
new kit in a variety of environments and with a wide range of products.
One of the key roles of Campden BRI is to help bring these parties together - to ensure that the latest developments become a practical reality as quickly as possible. It is to everyone’s advantage to deploy the most powerful technology quickly and effectively to support the production of safe, wholesome food.
Steve Garrett, Molecular Biology Group,
Campden BRI, and Julian South, Head of Chemistry and Biochemistry, Campden BRI, Chipping Campden Gloucestershire, UK.
www.campden.co.uk
matrices may make the method more accurate.
Acid test Another approach explored was the direct pH measurement of food products by non-glass pH systems using ion selective field effect transistor (ISFET) silicon chip sensors. Avoidance of glass is crucial in food production areas, to mitigate against potential contamination of the food. Te ISFET silicon chip sensor can be used as an alternative to glass electrodes for pH measurement and is robust enough to be used on the production line. Te probes are designed for rapid analysis of liquids or semi-solids and some systems can
variable temperature of the chickens affected the probe measurement, with repeated calibration being needed. Tus it is important to evaluate any new instrumentation in a factory environment to be sure it is robust enough.
Looking to the future As instrumentation continues to evolve, with increased options for in-, on- and at-line analysis of raw materials, ingredients and products, many manufacturers will need independent assistance in identifying, assessing and implementing the new technology. Conversely, manufacturers of instrumentation are seeking independent assessment of
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