Hygienic Powder Processing

In reality food safety risks exist along the whole of the food chain – from farm to consumer. The Nutritionals market is not without its share of scandals, and in the Infant sector of this market it’s a risk too high to bear!
The word ‘Hygiene’ encapsulates both the need for cleaning, but also for avoiding any cross-contamination of ingredients. This is all too likely a risk nowadays, with the diversity of ingredients being used and the need to frequently change recipe. Often processed in systems that were designed and fit for purpose a decade ago.

What are the risks?
Looking more closely within a dry powder mixing factory the main risks are:

  • Residual product from previous recipes being left inside the processing & handling equipment, which then contaminate the next batch through the system.
  • Cross-contamination from airborne dust returning back into the process line via open hoppers & transfers or by operators.
  • Bacterial growth due to moisture still being present after wet cleaning.

This report will look at why these risks are still apparent and how to overcome/reduce them.

The risk of residual product
Cleaning and removing any trace of a previous recipe is easy as long as you have unlimited time, people and cleaning media at hand. However, how often is that a reality? It is not uncommon for entire shifts to be used for cleaning down a line, before a change can be made.
Traditional long pneumatic conveying pipes represent a huge risk. They are cumbersome to clean and how can you swab test them when the procedure is completed?

Large fixed mixers and hoppers are only marginally better, they take a long time to clean too. Who wants to get inside a blender to clean it and thereafter swab test every potential catch point?
Campaign producing from ‘white to black’ just results in more inventory and has its own risks of wastage in respect of shelf-life reduction.

Cross-contamination from dust
Attempts to break up the long pipework or in-line processing equipment by using tilting aluminium totes and big bags might have enabled easier cleaning, but they have just transferred the problem elsewhere.

Due to the open transfers and open-mouthed discharge stations, excessive dust is generated within the working environment.

Violent cleaning methods covering ‘ceiling to floor’ result in unnecessary utility usage as well as risking the fabric of the building itself, and yet still the critical contamination points may not be cleaned.

In a bid to overcome this, overuse of dust extraction has been employed, which has then led to poor yields and moving the problem on further down the line.

Milk and water don’t mix
A further problem exists after cleaning. If all traces of moisture are not removed then there is the danger that bacteria will grow in these droplets and contaminate the whole process. With pneumatic conveying or continuous mixers this can result in a very large batch of product that has to be scrapped.

So what can be done?
Matcon have been working with leading manufacturers installing our IBC (Intermediate Bulk Containers) systems which overcome these issues thanks to changing the con¬ceptual solution, as well as being due to the simple nature of the IBC design.
The system remains closed at all times so there is no product leakage during transfer. This offers the potential to handle the containers within a ‘grey’ area, thereby saving significant building and operational costs.

Automatic docking units (ADUs) can be used to automate the filling process where high throughputs are required. The lid of the IBC is automatically removed and replaced, eliminating the need for operator involvement and reducing the cost of manpower.

All blending takes place within the IBC itself, so there is no time-consuming cleaning after each recipe, the Blender is simply ready for change after change.

IBCs are cleaned off-line, thereby minimising the disruption to the manufacturing flow. All that is left to be cleaned is the filling area and packing lines.

What about a quick clean solution?
Using Matcon’s latest technology our customers have found that dry cleaning of the IBCs is a viable option.

Very low amounts of residual powder (1-10g of product) exist after an air-wash, which means that the IBC can be used round the cycle again. Recipe changes can be accommodated as IBCs can be dedicated to particular ingredients or assigned to allergens and non-allergens, with IBCs kept in a holding pattern until they can join the process flow again.

Dependent upon the nature of the powder, wet cleaning can be performed for a full detergent clean after a number of runs round the cycle. This removes the risk of bacterial growth as the dry cleaning is sufficient and the intermittent wet cleaning allows enough time for full drying and validation of no moisture presence.

The inside of the IBC is smooth with generously radiused corners and a single piece hygienic cone valve which can either be removed for cleaning or cleaned effectively in situ on the specially designed wash station.

Further advantages of the System

A further advantage of the Matcon IBC System is the fact that these are constructed from food grade stainless steel and do not have the problems associated with aluminium which the tilting totes are made from.

Matcon embrace EHEDG (European Hygienic Engineering & Design Control) and their design philosophy for making equipment easier to access and clean. These guidelines can be read at www.ehedg.org. EHEDG encourages the reduction of flat surfaces & hollow bodies. Whenever these are impossible to remove for technical reasons, there must be a means to check their integrity, which is integrated into the standard Matcon design.

The operation of the unique Matcon cone valve means that the feed of powder from the IBC to the downstream process is controlled, enabling ‘on demand’ refilling, without the need of a cross-feeder. These cross-feeders with their rotating screw in a stainless steel tube, inevitably carry the risk of creating metallic particles, degrading fragile spray-dried powder not to mention the difficulty in cleaning and validation.

The Evidence!
One of our key customers, Nestlé have given us a testimonial. The most essential part reads:
“We have extremely strict and tough hygiene criteria during the manufacture of all our products. Minimising the risk of any contamination or cross-contamination in our production system is for us paramount. We have recently incorporated Matcon’s IBC system for the storage of intermediate powders prior to mixing and packing in several of our manufacturing sites around the world due to its fully enclosed transfer system which enables us to almost eliminate any hygiene and contamination issues from this area of our system.” (Peter Suess, Chief Engineer Nestlé Germany, Benelux & Nordics)

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