Foodstuff Production Methods

Consumers are repeatedly confronted with scandals in the foodstuff industry, most recently the Fipronil egg scandal which took place in the laying hen farming industry in the Netherlands and Lower Saxony (Germany). What do foodstuff producers and marketers do to avoid cases like these? The increasing costs in the area of modern foodstuff analysis suggest that they do a lot.

During the last decades, newer and more sophisticated processes have been developed with the most sensitive detection thresholds (ELISA, PCR or the mycotoxin analysis) in order to reduce or eliminate sandals like these and the dangers they pose for consumers. Methods for sample preparation of the most diverse matrixes have now been developed.

There is often difficulty regarding comminution, for example, the volatile components or the rheological properties of a material which can only be prepared without using regulating factors (sieves). As a result, knife mills are often used. FRITSCH offers the Knife Mill PULVERISETTE 11: an industry quality knife mill.

Here are some examples of the comminution of foodstuffs and their backgrounds.

Hopfen und Malz Gott erhalts

This traditional German saying asks for God’s blessing for malt and hops. Hops are known and used for the production of beer but show much more diverse pharmacological-effect aspects. Many components contribute to the anti-inflammatory or soothing effects of hops including certain plant dyes and secondary plant substances like humulene and caryophyllene. It is possible that they contain a species-related mechanism of action similar to the body’s own sleep hormone melatonin. Fresh female hop cones were comminuted and homogenized in the PULVERISETTE 11 at 4,000 rpm for 15 seconds so that this could be examined in detail.

Hop cones before and after the comminution

Figure 1. Hop cones before and after the comminution

Hops milled at 4,000 rpm, grinding time 15 seconds

Figure 2. Hops milled at 4,000 rpm, grinding time 15 seconds

Mandatory Labeling of Sweets

Fruit flavored hard candy normally needs to be mechanically processed in order to identify vitamins or other ingredients. Achieving a realistic random distribution seems difficult using the commonly utilized HPLC because it only uses a sample of a few milligrams. The high sugar content and the vitamin content can be problematic during the sample preparation process. Using liquid nitrogen to embrittle the candy and change its breaking behavior seems unavoidable. This helps to guarantee the vitamins remain a stable temperature.

Hard candy with liquid centre, embrittled in nitrogen

Figyure 3. Hard candy with liquid centre, embrittled in nitrogen

The Knife Mill PULVERISETTE 11 can also carry out this procedure. Firstly, the candy is embrittled in the stainless-steel vessel and then there is a brief comminution at 5,000 rpm which only lasts for 20 seconds. This creates a finely distributed powder without an excessive application of energy.

Comminuted hard candy after 20 seconds

Figure 4. Comminuted hard candy after 20 seconds

On the Trail of Mycotoxins

Mycotoxins are metabolites of mildew, for example, Aspergillus niger or Aspergillus flavus, and present a health risk for the consumer. They also cause economic losses because there is an enormous quantity of spoilage due to mildew if an infestation is not identified. Aflatoxins are especially significant because they are carcinogenic even in very small quantities.

Consequently, the detection limits are in the range of a few µg/kg. Spices or nuts of any kind are especially susceptible to these “mildew nests.” Due to the formation of nests in these material samples, the laboratory requires a relatively large sample in order to be representative. As a result, approximately 800 grams of hazelnuts were processed during the tests with the Knife Mill PULVERISETTE 11. The sample was initially processed in three x five-second intervals at 4,500 rpm and then it was homogenized again for a further 15 seconds at 6,500 rpm.

Approximately 800 g hazelnuts

Figure 5. Approximately 800 g hazelnuts

Hazelnuts after 30 seconds grinding in the grinding vessel made of stainless steel

Figure 6. Hazelnuts after 30 seconds grinding in the grinding vessel made of stainless steel

Homogenous sample of hazelnuts

Figure 7. Homogenous sample of hazelnuts

This information has been sourced, reviewed and adapted from materials provided by FRITSCH GmbH - Milling and Sizing.

For more information on this source, please visit FRITSCH GmbH - Milling and Sizing


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