Responsibility for ensuring the safety of processed foods ultimately rests with food processors. HACCP (Hazard Analysis and Critical Control Point) principles state that food processors must follow a systematic way of identifying food safety hazards and making sure that they are being controlled day-in, day-out.
While this principle has been willingly accepted and practiced by food processors, one of the primary challenges is in maintaining sanitary secondary operations in the production line, after a protein (beef, poultry or seafood) is cooked. For example, slicing, slitting, washing, conveying and packaging.
When a protein leaves an oven it is free of pathogen and bacteria – the processing of high-temperature cooking takes care of that. However, risks of contamination begin to rise after the product begins to cool or, in some cases, after it has been chilled.
Because many processing lines run for 16 consecutive hours, the opportunity exists for bacteria growth throughout the day. Unless secondary equipment is sanitised properly at the necessary intervals, pathogens and other bacteria can build up on this equipment and contaminate product as it moves down the line. Pathogens can lead to final products that present a public health risk and bacteria can dramatically reduce shelf-life.
In meeting these food safety challenges post cooking, it is critical to understand the relationship between food processing equipment manufacturers and food processors.
As a manufacturer of thermal food processing equipment, customers look to Unitherm Food Systems for solutions to all kinds of thermal processing challenges including grilling, roasting, cooking, pasteurising, and chilling. Sometimes those solutions include collaboration with manufacturers of other specialised equipment.
Unitherm recently faced such a challenge when Founder and Chairman David Howard mapped out an solution that could prevent the growth of pathogens and bacteria that occurs on slitting equipment used to cut cooked beef and chicken strips for products such as fajitas. The issue of potential contamination post-cooking first came to Howard’s attention three years earlier when he was invited, as an expert in food safety, to identify and help solve an e-coli problem in a new processing plant.
While he was there, he noted that the critical exposure time that occurred to proteins after the cooking process and through to the final packaging created some serious potential food safety issues. There were surfaces where bacteria could grow throughout the day, and the meat traveled over those surfaces.
“At the point when the meat exits the oven it is pathogen-free,” explains Howard. “Then it goes through the slitting blades, and all of the product becomes intermingled. If there is a pathogen or high bacteria count present on the blades, every single piece of meat that goes through there could have the opportunity to be contaminated.”
To solve the problem, Howard envisioned a system in which the meat would come out of the oven and fall directly in the meat slitters and that this and other items (such as the conveyor belt) could be designed to be self-sterilising during the production process. At the end of that line, the product could then be immediately packaged.
The concept was unique in another aspect by using steam instead of conventional chemical cleaning techniques.
The conventional method processors use to prevent bacteria growth is by cleaning the equipment with appropriate chemicals. This method calls for frequent checking of the bacterial load by swabbing the equipment and measuring the growth, then treating it with chemicals as required. Pathogens are another matter. Pathogens on surfaces that come in contact with the product can grow a biofilm that can mutate and become resistant to chemicals.
Steam, on the other hand, utilises energy – not chemicals – to instantaneously kill pathogens and/or bacteria.
“Steam is superior to chemical cleaning because pathogens can mutate and become resistant to chemicals,” Howard says. “Because the slitter is placed at the exit of the oven and does not touch any other surface it remains pathogen-free. At that point you could proceed directly to final packaging.”
Trouble is that although Unitherm offers a variety of thermal processing, chilling, pasteurising, and even hygiene equipment they are not in the business of manufacturing slitters or supplying conveyors.
“As a company that doesn’t make slitters, it can be frustrating, says Howard. “You know there’s a solution that will make the process safer, but you can’t necessarily just do it because it is outside of the scope of what your company offers.”
The strategic alliance
To realise his vision of a self-sterilising slicer/slitter using steam, Howard was faced with the dilemma of either manufacturing such a product at Unitherm, or finding an existing manufacturer willing to engage in a joint partnership to develop the new concept.
Howard quickly dismissed the idea of creating the product in house, however. “There are plenty of companies in the world that make slicers and slitters. It makes no sense for Unitherm to say, ‘Us too. Here’s a one-off,’ he explains.
Instead, Howard contacted Bob Grote of the Grote Company, whom he has known for 30 years. The Grote Company is a leader in automated slitter/slicer/applicator systems for food processors to slice, stack, portion, count, and arrange virtually all types of food products.
“They are a very reputable company with a solid management team that you can go and talk to about innovative ideas. They are very open to looking at [potential] process improvements,” says Howard.
As expected, Grote was open to the idea of a strategic alliance.
“A few years ago I recognised that we had to begin doing business a little differently to truly optimise what we have to offer our customers,” explains Bob Grote, vice president. “Not having expertise in every field that is associated with our company, I came to the conclusion that strategic alignments would be very beneficial to not only us but to the food processors.”
The design concept Howard outlined, which is now patent pending, was to build a machine that could be attached to the end of Unitherm’s spiral ovens. The slitter could be used inline and then rotated out of the way when not required. Based on the actual bacterial counts measured, steam would then be applied to the blades at specific time intervals to sterilise them.
Grote engineers provided the initial equipment design within only a few weeks. Unitherm then made additional suggestions and tweaks so the equipment would meet specific production requirements.
“We make a variety of sliders and slitters, but haven’t incorporated steam sterilization into any of our equipment before,” Grote says. “The trick with this slitter was to modify it to accommodate and trap the steam and add a jacket or shroud around it to contain the steam. We also had to make adjustments to the materials we used in the slitter itself to allow for the higher operating temperatures.”
In operation, the combination slitter and steam steriliser is placed right at the exit of the oven. A steam shroud encloses the slitter, and steam is pulsed into the shroud in order to maintain the desired temperature range. The enclosed steam keeps the temperature at a level that will kill any pathogens or bacteria.
Grote adds that this self-sterilising slitting system still requires periodic cleaning, but those intervals will result in much less downtime than is normally required for conventional chemical sterilisation.
By agreement, Unitherm can sell the product for use on its spiral ovens and Grote is free to sell the product on Unitherm or any other oven manufacturer’s equipment.
According to Howard, Unitherm already has several self-sterilising slitters in operation at several food processing plants. He says that partnerships with companies such as Grote will continue to enable the offering of innovative products to the marketplace.
Howard is already working on another improvement related to packaging of the beef and chicken fajita meat. One option that would eliminate any additional contamination in the post-cooking and slicing process would be to have it drop into a bag that is immediately vacuum-sealed. This hot-fill technique would extend the product’s shelf life and eliminate the need to freeze it. Only chilling would be required.
Most food safety issues that exist in food processing have an engineering solution,” says Howard. “And if that solution requires expertise that is outside of a manufacturer’s business model or product offerings, then by entering into a strategic relationship with the right partner the solution is attainable. That stimulates revenue for those involved in the solution, but more importantly benefits many food processors as well.”