This inter-laboratory trial shows some striking results. Complete the text using the results of this trial.

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Not right. In the graph that shows the results of egg powder you can read that lab 7 was the only lab that used the Röse-Gottlieb method. They found lower total fat contents, because the Röse-Gottlieb method is only suitable for milk and milk products. This method is too gentle for other products.

Not right. When looking at, e.g. the results of biscuits, you can read that, generally labs using the Schmidt method found on average higher results than labs using Weibull method. The reason is that in the Weibull method after acid digestion of the sample, the digest is filtered on filter paper. During drying of the filtered residue oxidation of the residue can occur, especially of unsaturated fats. This results in a less efficient extraction compared to the Schmid method.

You are right. You have finished this part. You have learned that different labs use different methods to analyse fats in the same products. This is not always wrong, because there is no single standard method for fat extraction. However the current state of total fat determination is poor because there are considerable variations between and within laboratories: for exactly the same products sometimes very different values for total fat are reported also when the same method is used. Therefore it is important to ask the laboratory that analyses your foods, what kind of quality assurance procedures they use, how they perform in collaborative studies etc.

Below you find the results of an interlaboratory trial in which the fat contents of several products is determined by various experienced food labs. Study the results and answer the following questions.