A midwestern food processing company that has been in the business for 17 years processes fresh-cut produce and sells it to wholesale distributors. For 16 years, it used a controller that would no longer meet the demands of the growing business, and the company replaced it with a different unit.
Explore this issueAugust/September 2005
However, the new controller could not adequately maintain the customer’s required wash water parameters. This inconsistency in control required constant recalibration and monitoring of the equipment.
The processing company’s engineering supervisor estimates he and a fellow employee had to adjust the controller every half hour and spent on average one to two hours per day checking the controller.
“We let price factor too heavily into our decision,” recalls the engineering supervisor, “but we learned the hard way that you get what you pay for.”
The food processor only kept the replacement controller online for six months before getting a newer wash water quality control system, especially designed for the agriculture industry.
“This system did cost more than its predecessor,” admits the food processing company’s engineering supervisor. “But in the long run, we believe the operational cost savings will far outweigh the initial capital cost.”
Now only one person has to check the controller once a day. Thus far, the machine has not needed to be recalibrated. Chemicals are more efficiently used. And better bacterial control has extended produce shelf life to well over a week.
The addition of the newer controller has led to more product being sold and less being discarded on-site. Better disinfection and water quality have greatly increased the overall food safety of the processor’s product.
The Control System
At the processing company, the produce is first cut before it passes through a closed-flume system containing 36º F ingredient water for 20 to 30 seconds. The product is then spun and packaged.
The controller helps maintain a pH level that is not too acidic yet will provide a good chlorine disinfection rate. Controlling the chlorine and pH levels is important. If pH is too low, it will corrode tanks but boost chlorine’s effectiveness. If pH is too high, it will compromise the shelf life of the product and hinder chlorine’s effectiveness. Maintaining a pH of 6.8 to 7.2 at 700 to 750 millivolts is ideal. Chlorine works better at this lower pH, yet the dosage is high enough to disinfect and not cause chloramines to form. Water is typically disposed of between product runs.
The control system also combines industrial-duty sensor technology, UL/ CSA/CE design specifications and full-featured functionality. The 12-line by 40-character display and help-screens prompt operators quickly and easily through the system’s vast capabilities that include five different control modes, chemical inventory and process signal monitoring, DCS reporting and data logging.
The control system also comes with software that allows operators to remotely access the controller from a computer located up to 1,000 feet away and to receive system alerts via pager. The manufacturer also has the ability to troubleshoot the system from their facility in Bradley, Ill.
“Being able to download all the daily values for the ingredient water is invaluable,” adds the company’s engineering supervisor. “Moreover, the tool allows us to assure food safety for all of our customers.”
Making the Cut
In addition to the above features, the controller also has a time-based proportional control that alleviates overshooting set point. This, of course, results in additional savings for the food processing company.
“The system is definitely saving us money,” attests a company spokesperson. “Just in man-hours alone, we save at least one to two hours per day. But you can’t really put a price on peace-of-mind.”