Water activity is a useful parameter for many industries. Measuring water activity takes only a few minutes so can provide results quickly, ideal for critical control points.
However water activity is a qualitative measure therefore interpreting results can be complex. The following slides provide an overview to water activity and how to utilise Aw measurements.
For further information please do not hesitate to contact us or visit our webpage to download our latest AW White Paper!
Not clear on what water activity is? Check out our other posts on water activity here!
Water activity affects a wide range of products from pharmaceuticals to foods, here we take a brief look at five typical applications where water activity measurements are used.
Remember water activity affects biological, chemical and physical properties of products.
Application 1 – Food
Water activity is critical in food production, reducing water activity reduces the available moisture for spoilage organisms to utilise as such low Aw can limit or prevent growth and spoilage.
Aw is often used to screen raw ingredients or end products to confirm that they are within tolerance. Aw measurements only take a few minutes and can therefore provide immediate feedback. This can save time, money and prevent health risks or product spoilage.
Aw can be used as an excellent indicator of shelf life. Once a production process has been fine tuned to deliver products with suitable shelf-life, online aw measurements can confirm production consistency.
Classic methods to control Aw in food are listed below.
Application 2 – Paper
Water activity or %equilibrium relative humidity in paper may not be your first thought, but the impact of poor or changing ERH in paper can be very costly. Changes in ERH can cause paper to curl or lead to increased static both of which can cause paper jams. For an industrial printing company this can lead to costly downtime. ERH also affects the binding of inks, drying times and ultimately spoilage by moulds and fungi.
Application 3 – Pharmaceutical Products
Drug production and storage is one of the most highly regulated manufacturing sectors. All stages of drug production, storage and delivery rely on critical control of many factors including water activity. Most drugs must be stored in stable conditions hence the advanced moisture impermeable packaging used. Aw readings as well as humidity monitoring and control are utilised to ensure free water is maintained within tolerance.
Application 4 – Seed preservation and storage
Seeds present an interesting challenge, if Aw is too low the seeds quickly become non viable, where as too high and they may germinate or suffer spoilage through mould or fungal growth. One of the most critical seed preservation projects is the Millennium Seed Bank project. More details about how Rotronic AW meters were used is avaialble on the Kew Gardens website
Application 5 – Soaps and powders
Finally we come to good old washing powder, even with powders and liquids now packed into clever tablets and pods Aw remains critical. The materials must be stored in a way that ensures safe delivery to the customer but can be released once in contact with water in your washing machine. The science of behind the latest washing powders and liquids relies heavily on the measurement and conrtol of water activity and %ERH!
Hopefully this brief in site into how water activity affects so many day to day products has been useful. For more information visit our website or contact us to discuss!
JOWA AG Pasta has been the largest manufacturer of pasta products in Switzerland since it was founded in 1931. It is important for the company that its production operations run smoothly and meet strict quality standards.
Precision temperature and humidity probes from Rotronic are used to measure the climates in the factory’s six production lines, which predominantly manufacture dried pasta for the retailers such as Migros (Switzerland’s largest retailer). As a testament to the quality of Rotronic probes some units are over 15 years old and are still performing as required having only undergone routine calibration and adjustment to ensure that they provide consistently accurate accurate data.
JOWA AG manufactures 18,000 tonnes of pasta per year and is thus the largest pasta producer in Switzerland!
The pasta market is highly competitive and food legislation strict. It is therefore all the more important that the pasta is produced in the finest quality without production stoppages and rejects. The drying process plays a key role in the production of dried pasta and is therefore accorded top priority at JOWA. In order to control the climates optimally, temperature and humidity probes from Rotronic are used in the production lines. To preserve the food for a long shelf life and prevent mould and negative microbiological processes, the pasta is dried to a very specific level. Over drying wastes time, energy and produces a poorer quality product, under drying reduces shelf life and risks spoilage. Humidity and temperatures therefore need to be monitored closely during production. Legislation in Switzerland states that pasta products may not contain more than 13 percent water.
High Demands on Probe Accuracy
JOWA has been manufacturing pasta at its site in Buchs AG since 1963. The requirements of food standards, law and customers are rising continuously.
Spaghetti Production!
Oliver Höfler, head of the JOWA AG sites Pasta Buchs & Mühle Wildegg, comments:
“Every single production step needs to be traceable in ever more detail, down to each single packet of spaghetti. The temperature and humidity of each production step must be recorded exactly.”
If unwanted temperature and humidity variations were to occur in the pasta, this could lead to quality defects such as crumbling. The pasta would then dry irregularly and break during cooking. For this reason a sample is taken of every product from the first three and last three pallets for quality assessment. The heads of the different departments evaluate the products daily according to various specified properties such as taste and appearance.
Oliver Höfler explains: “If we have to recall products from various stores, this means an enormous financial loss of several ten thousand francs and also a severe blow to the image of our products. A dissatisfied customer – that is something we cannot afford. For this reason it is essential that we are able to rely on the measuring accuracy of the Rotronic probes to 100 percent.”
In addition to this, samples need to be taken for analysis from ongoing production every four hours. “ We greatly appreciated the open and transparent collaboration with Rotronic.” Oliver Höfler, JOWA AG, Switzerland Migros dried pasta perfectly monitored. Rotronic I200 sensor, providing reliable service for more than 15 years.
Project Workflow: Good and Long-Term Planning
Planning calibration time is the key to success with humidity instruments. JOWA AG in Buchs stops production twice a year, two weeks in winter and two weeks in summer, in order to check all equipment and machinery and so maintain the high quality standards. Andreas Zülle, head of production, ensured that the 50 probes (both the I200 transmitters dating back to at least the year 2000 and the newer HygroFlex5 generation) were disconnected right at the start of the last inspection so that Marko Schulze, Rotronic’s qualification technician on site, could begin calibrating the measuring devices. All probes were also catalogued. Marko Schulze: “JOWA’s planning was ideal, I was able to check all probes and either get them back into shape or replace them, and then we still had enough time to test the newly adjusted probes.”
The HygroFlex5 series of transmitters connect to our entire range of HygroClip probes and offers analogue and digital outputs for any application.
HC2-S probe provides superb precision and state-of-the-art functionality, taking humidity and temperature measurement to a whole new level of accuracy < 0.8 %rh and < 0.1 K at 23 °C.
Also available with ATEX / Intrinsically safe certification.
Smooth implementation of the inspection and calibration procedure was important to Andreas Zülle: “After the calibration, our process specialists were able to start up the production lines again without problem.” Oliver Höfler adds: “We greatly appreciated the open and transparent collaboration with Rotronic, found Marko Schulze to be an extremely competent partner and are sure we will be able to carry out calibration of our instruments even more efficiently next time. They have now been catalogued in detail. On top of that, we can also check the probes during operation with the Hygropalm from Rotronic.” Both sides benefit from good planning and a good working relationship.
Some Interesting Facts about Jowa
JOWA Pasta has been producing dried pasta for more than 50 years
The durum wheat semolina needed for production comes from a mill in Wildegg that also belongs to JOWA.
A team of 46, working three shifts a day, ensure daily that high-quality raw materials are transformed into products at an optimum price-performance ratio .
JOWA employs a workforce of around 3,200 people and, with more than 140 apprentices and trainees, is the biggest training company in the Swiss bakery industry.
JOWA AG is the leading Swiss bakery and supplies its customers from the retail trade, convenience stores and food service sector daily with a wide range of products and individual service concepts.
Jowa produce buns, cream slices to pasta, ham croissants and braided bread, some even gluten-free – the bakery assortment goes far beyond the classical bakery range.
The service concepts are tailored specifically to the requirements of customers and extend from logistics and marketing to in-store production.
The tasty JOWA breads and pastries are very popular.
JOWA breads are served fresh on the table daily in every third Swiss household.
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