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Making the food factory sustainable

21 January 2019

Suzanne Gill reports on the presentation highlights from the ‘sustainable food factory’ session of the Appetite for Engineering event, which took place in October 2018. 

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Opening the ‘sustainable food factory’ session, Eric Partington, chairman regional section of the European Hygienic Engineering and Design Group (EHEDG), set out to explain the important role played by hygienic design for a more sustainable factory as well as to ensure food safety.  

Partington set the scene by explaining what ‘hygienic’ means. “In the context of food production, making hygienic choice means specifying equipment and plant constructed from hygienic materials and designed to be hygienic. It also means putting it all into a hygienic building.” 

Hygienic machines must be resistant to the build-up of process soils and should be easy to clean between uses.  Partington argued that, while this may sound simple, in practice making the rights choices may not always be so easy as not all materials are inherently hygienic and in reality not all equipment or processes are designed to be hygienic.

Despite the stipulations of the Machine Directive 2006/42 EC, which covers hygienic design, Partington took the audience through a series of screen shots which pointed out some commonly found hygienic design faults – including poorly designed pipework sensors, flanges and bolts. While many of the design errors looked obvious when explained to us, in real life many of these faults will be hidden from sight in closed systems so may go unnoticed, but can still lead to product cross-contamination issues as well as providing a perfect environment for micro-organisms to thrive.

Partington went on to point out that not all production facilities are hygienic either, and he highlighted the importance of addressing the hygienic status of any product contact surface in a production area. “This includes any surface which might transfer its constituents to the food,” said Partington. “In addition to the preparation surfaces, also consider any overhead cable trunking or beams or any cold surface from which condensate could drip onto surfaces that food may touch.” 

He reminded us that contamination does not always come from above. It can also come from below the production line.  As soon as a hose is directed onto floors and drains an aerosol of any contamination will immediately envelope the production area.”

Partington went on to explain the origins of EHEDG which was conceived by Unilever in 1989 when it suffered from multiple food contamination issues. Despite its best efforts to clean the plant between production runs, contamination and spoilage organisms were still being carried from one batch of food to the next. Unilever realised that if its cleaning regime was not at fault then the problem must lie with the equipment. With a number of Unilever’s competitors across Europe suffering from the same problems they got together to create EHEDG. Today it also helps identify best-practices in hygienic operation and its guideline documents can be downloaded from 

EHEDG has created a series of test procedures for determining cleanability. The equipment under scrutiny is deliberately contaminated with a special medium. It is then cleaned according to the vendors recommended procedure and then examined for residual organic material. Any surviving contamination will indicate either a design inadequacy or that the specified cleaning regime was inappropriate. “There is a tendency to assume that CIP operations are fool-proof, but this is not always the case. If plant is old or difficult to clean then CIP may not be completely effective.” 

Hygienic payback
While UK law requires industry to be able to demonstrate that equipment used for food production is hygienic, Partington pointed out that there is a much better reason. “The speed and ease with which hygienically designed equipment can be cleaned is dramatic in contrast to that of less hygienic equipment,” he said. Hygienic design will offer savings in the quantity of water and cleaning solutions required for cleaning, and the cleaning process will much quicker too, freeing up staff to undertake more productive tasks. 

“There really is no reason for anyone to not strive to use hygienic equipment,” concluded Partington. “Maintaining and improving both product quality and hygiene is the common goal of food producers, processors and food distributors. It is also supported by legislation so relinquishing this objective should not be an option for anyone in the food industry. Indeed. It should also be considered as an important tool to help increase efficiency and productivity.”

Continuous improvement
Next onto the stage was Ed Pooley, continuous improvement manager for British Sugar’s Bury site who set out to explain the project delivery method deployed at British Sugar which uses Lean and Six Sigma strategies. 

Lean is about reducing waste in a process, including time, while Six-sigma is about variation and defect reduction in the process. Pooley explained how his team employs a structured project framework called the DMAIC Cycle (Define, Measure, Analyse, Improve, Control). He focussed on a single project from the 70 that his team are currently overseeing – which had the goal of reducing compressed air consumption across the site. This project has resulted in a 15% reduction in compressed air energy usage, equating to savings of around  £25,000.

“Every year we are tasked with looking for ways to make sustainable cost reductions,” said Pooley. “The first step of any project is always to define the problem but, for the compressed air project we had no way of doing this as we were unable to measure the cost of the compressed air used across the plant. So, we brought someone in to audit the system and this showed evidence of waste in the system due to multiple air leaks in the system.”

Next, the team set out to solve the problem of how it could measure compressed air usage by talking with its sensor supplier. A solution was provided –  a non-intrusive ultrasonic flow measuring device which can measure gas and liquid. With the flowmeters installed the team soon started to gain some useful data about the site’s compressed air usage and was able to identify some distinct operating periods – even down to lunch breaks – when fewer people were using pneumatic equipment.

“Measuring is all about understanding the current state so our first step was to manually walk the process and look for waste. We soon found it,” said Pooley. “We found that compressed air was still being produced when it was not needed, in addition to the number of unaddressed leaks in the system. A quick win to solve this problem was to produce ‘leak tags’. In addition to reporting leaks, staff were also asked to hang a leak tag onto the pipework at the point of the leak so the maintenance team could quickly find the problem.” Air leak tag stations were set up across the factory with instructions on what to do if a leak is found.  In the first phase of the project over 60 leaks were reported. 

Tackling compressor efficiency was the next step. “With fewer leaks we were able to reduce the quantity of compressed air being produced. We replace a fixed speed compressor with  a variable speed system. We also implemented some process automation on the system to ensure that the compressor is always working at the correct system pressure, according to need. This solution has halved the total power consumption on an average day,” said Pooley.

The most important criteria of any improvement project is being able to account for it. “It is important to collect data before, during and after a project so that you can see what you have achieved,” said Pooley. It is also important to ensure that any changes continue to be implemented. “Create a control plan document that can be audited at regular intervals to ensure that the new way of doing something continues to be implemented and to ensure that the new system is sustainable,” he advises. “Once you have identified a cost-saving opportunity and actioned a solution, it is vital to ensure that the solution is sustainable. So always make sure that you have a robust control plan in place to ensure that any beneficial changes become standard practice. The smallest of changes in terms of process management can offer huge financial returns.”

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