The number of food recalls and their cost to businesses and society are rising. A contaminated product can cause sickness for the consumer (or at its worst, death) and multi-million dollar losses for the company along with reputational damage. Although the World Health Organisation is promoting efforts to improve food safety from farm to plate and the Hazard Analysis Critical Control Point system identifies wher hazards might occur in the food production process and puts into place stringent actions on prevention, it is still very much the responsibility of the manufacturers to ensure that food allergens are minimised as much as possible.

There are over 170 foods known to provoke allergic reactions, of which the most common are found in everyday sources such as milk, eggs, shellfish, wheat, nuts, seeds, fruit and soya. Even tiny amounts of the allergen can cause a reaction so strict controls and regulations need to be present to ensure total integrity of the final product.

In the world of powder processing, a major challenge which manufacturers face is how to handle an ever increasing portfolio of products which use a diverse range of ingredients, all within the context of reducing manufacturing costs, minimising product waste and achieving superior product quality and safety for the consumer.

WAITING IS NOT PRODUCTIVE

Traditional powder manufacturing plants that use fixed in-line mixers and pneumatic conveying can prove to be problematical when handling allergens. For a start, they can be complicated to clean. once a batch has been processed, the whole operating line needs to be shut-down for thorough wet-washing and drying. This can take a whole shift depending on the design and size of the processing line. For some lines, this can also involve a considerable amount of manpower for cleaning.

Any traces of allergen must be eliminated from the production line and verifying this can be very time-consuming and costly in itself. Often bakery product manufacturers will send a batch of flour through the process line after cleaning, and then examine it for allergen content. If the smallest element is detected, the whole line is washed again and retested. This is costly both in terms of time taken and the waste of product used for these validation purposes.

As high costs are involved with recipe changes, some manufacturers adopt campaign manufacturing— running larger batches through the system than the initial order. This system looks better on paper from an equipment efficiency point of view and ensures stock for future orders, allowing the company to respond quickly to such requests. However, the building up of inventory ties up cash and is at risk of obsolescence if not properly managed.

Management of dust in the environment is also critical. Products need to be separated wher there is an allergen risk. For some manufacturers, this means placing production in different buildings rather than just separate lines or creating specific hygiene zones with dust extraction systems, all at great expense.

THE CASE FOR CHANGE

In 2012, a major UK-based bakery company began the first phase of a US$3.9 million (£2.5 million) investment to improve their production flexibility in order to accommodate small batch runs, high recipe variety and to more efficiently handle allergen ingredients.

The original facilities were centred on two vertical conical fixed mixers fed via a conveying system from silos holding flour and sugar. Other ingredients were then added from big bags or sacks via mechanical conveyors. The company recognised that this system was not going to be flexible enough to cope with smaller batch runs. Each mixer was taking four operators almost half a shift to clean, resulting in 22 percent downtime for cleaning alone. Like many manufacturers, they coped by campaign manufacturing, which led to expensive inventory potentially going to waste in their warehouse.

With the intent to find a better manufacturing solution, the company looked for a supplier to provide a more flexible system that could sit alongside the existing manufacturing equipment, which would continue to be used for the high running, low variety recipes. An Intermediate Bulk Containers (IBC) system was seleced as it could be installed in a small footprint but offer maximum production flexibility.

IBC AND FLEXIBILITY

As powder materials are transported throughout the production processes in IBCs (also known as bins), cleaning can be done off-line rather than requiring a full shut-down of production. This permits a full clean of the IBC with water (and detergent wher needed) allowing sufficient time for thorough drying. The simple design of the bin stops any particles being trapped and allows for easy inspection and validation.

Furthermore, with in-bin blending, the ingredients are mixed in the IBC itself rather than coming into contact with any mixer blades, which means that there is no need to clean the blender between recipes even when an allergen is present. For the bakery company, this reduces the time needed for cleaning from 480 man hours to just 70 man hours. As there is no need to clean the mixer, it can be switched to a new recipe immediately, ensuring a high Overall Equipment Effectiveness (OEE) rate and quick response to customer orders. In fact, the company managed to release US$271,224 (£175,000) cash by significantly reducing the inventory that it needed to hold.

They have also discovered that the IBC is guaranteed to always completely discharge all its contents. This Quality by Design (QbD) gives them added reassurance throughout the IBC system.

As the IBC system remains closed at all times including during the discharge process, the risk of dust being created or entering the system is significantly reduced. This means that allergens can be handled in the same building, thereby reducing the need for separate areas or hygiene zones. Due to this closed nature, multiple recipes can be produced simultaneously.

HOW CAN YOU MAKE SIMPLE CHANGES?

An IBC system might not be for everyone. Manufacturers who have invested heavily in a fixed mixer should maintain their current status. However, what can be easily changed is for IBCs to be used to decouple the mixer from the filling and packing processes.

With a fixed mixer, all the process steps are linked together. This means that while the mixer is being loaded with ingredients, the packing lines sit idle and when the mixing is complete, the filling stage has to wait for the packing lines to take all the material out of the mixer before it can be refilled and the next batch processed.

If the pipes are removed and IBCs are used to transport the material between processes, the mixer can be loaded at the same time as the packing lines are running. The mixer is offloaded into a number of IBCs and then immediately ready for refilling. These IBCs can then be taken to feed the packing lines and take as long as they need to use up the material in the IBC as other IBCs can be used to go back and take the next mixed batch out of the mixer.

This decoupling will help reduce the line down-time for cleaning. Often manufacturers will have the mixer shutdown for cleaning while the IBCs are used to feed to the packing lines and others are being filled with ingredients in readiness for the mixer to be back in action. In some cases this has been shown to double the capacity of the line. It does not remove the risk of cleaning out the allergens from the fixed mixer, but it certainly helps to improve efficiency and the cost of production.

It is possible to decouple the fixed system part by part using IBCs, rather than making a complete switch to an IBC system in one go. This can be done in two stages:

• Decoupling mixing from packing: this can double the capacity of either/both pieces of equipment, especially wher frequent cleaning is a necessity.

• Decoupling material batching from mixing: this typically increases available process time (and thereby efficiency) by approximately 50 percent or more. The bigger the batches, the greater the time-saving normally gets as the period it takes for an operator to load the mixer is directly related to the volume of raw material required.

LOOKING AHEAD

The widening of consumer tastes to include more varied ingredients and the globalisation of the food supply means that the risk of allergen contamination is ever-present. Lean thinking combined with flexible and agile IBC technology has the potential to dramatically improve the efficiency and profitability in any business and reduce the risk of allergen contamination.