How to enable consistent fried food quality

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Regular cooking oil testing can help operators keep fried food products consistent.

Testo’s product manager – food industry Ashton Baylis advises that distributors should specify a cooking oil tester when outfitting commercial kitchens with fryers:

Consistency is one of the most important components of the fast food industry. In order to keep loyal customers satisfied, restaurants need to be able to supply the same great product their customer base have come to know and love, every time, without exception.

You might think for the larger chains this is an easier feat, due to the highly regimented quality management in place. In fact, there are issues in maintaining standards at both ends of the spectrum. On the one hand, larger chains can have difficulties because of the sheer scale of their business. Whereas for individual restaurants and small chains budget is often tight.

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Cooking oil ages as a result of many factors. With relation to deep frying, these can include what food was fried, the temperature at which the oil was heated and the amount of times it was used. The quality of cooking oil also decreases due to time spent at room temperature, causing an oxidation reaction between the air and the oil.

Until recent years, there hasn’t been any sure way of knowing when to change cooking oil, with many businesses either changing it on a certain day of the week for instance.There are two major risks involved with these types of imprecise methods; first of all, in many cases restaurants are changing their oil too frequently, in which case they are wasting money on oil costs. More worryingly, sometimes restaurants are using oil which is way past its best, which can result in very oily, unpleasant foods, and in some extreme cases the product not being cooked properly.

One major difficulty is, in the UK not a lot has been done to improve the education of frying, outlining the necessity to ensure the products created are of the highest standard and that food safety is always considered. This is partly down to the lack of official legislation in the UK for cooking oil quality (such a legislation is tipped to be on the way however).

So this then begs the question, how are these massive, multinational companies able to supply such consistent, fried products across the world? The answer: regular cooking oil testing. Whilst this seems obvious, a significant number of restaurants in the UK are yet to introduce a process for measuring their oil, and many are even unaware such a solution exists.

Well the good news is, as of a few years ago, scientists discovered an accurate way to measure quality. Extensive research revealed the most effective way to check the age or quality of cooking oil is to test the Total Polar Materials (TPM). Too high levels of polar components illustrates that the cooking oil has been over-used and is no longer of acceptable quality.

Using an instrument such as testo’s 270 cooking oil tester on a regular basis, it can be determined within seconds whether cooking oil needs changing. By simply inserting the tip into the oil, depending on the screen colour, the user can determine whether the oil needs changing or not. A green screen means the oil is perfectly fine, amber is when it’s on the brink, and red means the oil needs changing immediately. With an instrument such as this, the process of testing cooking oil is now just a simple spot check for restaurants, and is fast becoming an essential part of any quality management process which involves frying.

Tags : cooking oilfryerstestingtesto
Clare Nicholls

The author Clare Nicholls


  1. I fully endorse this type of tester that is available from Testo. One point to add is that the different types of oils all have different TPM starting points that mean the any type of oil tester needs to be calibrated to the type of oil used. I have had first hand experience in this matter whilst working at Valentine Fryers. We trailed the two early Testo models, one having a traffic light type read out, the other, far more accurate, having a numbered read out, clearly showing the TPM reading.

  2. The UK are way behind Europe on legislation on cooking oil. in Europe operators found to have a high level of TPM can be fined or their premises closed.
    We have trialed various TPM measurement devices and find the Testo and Vito readers to be the best.BUT one of the customers that did try them said that in some premises they found the food tasted better when the oil was above 25% TPM!
    legislation will help make what is acceptable crystal clear.

  3. There is no substitute for correct oil management in regards to serving the best possible fried foods to a customer – not only should the quality of oil be checked daily by an oil tester such as a VITO or Testo oil tester – however in order to achieve full oil management this must be carried out with cooking oil filtration under pressure as per the VITO oil filtration range of products.

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