In today’s food industry, dust produced during the processing of bulk powders raises significant concerns. Within any factory there are numerous factors to consider, including health and safety, cross-contamination, efficiency, and waste.
Common food products causing dust hazards include cereal ingredients, spices, egg shell dust, flour, corn starch, sugar, and flavoring additives. Concerns also arise with dairy products, infant formulas, cake mixes, and cocoa powder, among others.
Bulk manufacturers whose production line requires bags of ingredients to be opened and emptied are faced with several challenges in relation to dust emissions during this simple yet essential step in the process. This article addresses these demands and how they can be met with the use of automated solutions that enhance efficiency and reduce waste.
Occupational Asthma Affects 15% of Asthma Sufferers
Health and safety refers to the regulation and enforcement of workplace welfare, with manufacturers legally obliged to comply with Occupational Safety and Health Administration (OSHA) regulations.
Occupational asthma is often caused by workers inhaling dusts that are respiratory sensitizers and affects around 15% of adults with asthma. According to the American Lung Association, it is the most common work-related lung disease in the U.S. In Europe, the issue comprises 33% of food industry compensation cases.
To avoid operator exposure to a dusty environment, the regulatory body suggests using wet operations when possible. However, for bulk suppliers who must discharge large quantities of dry ingredients from one station to the next, this is not always an option. Companies must control dust emissions within enclosed facilities to eliminate the risk of harm to human health and maintain adequate measures to remove unwanted dust within the production facility.
Avoiding Contamination under the HARPC
Food safety must also be considered in the context of dust control. Changes to food safety are driven by the Food & Drug Administration’s (FDA’s) Food Safety Modernization Act (FSMA) standards. Rather than targeting specific foods or hazards, the FSMA rules focus on implementing mitigation strategies in registered food facilities.
The new law impacts the longstanding Hazard Analysis and Critical Control Point (HACCP) principles, which have been superseded in the U.S. by Hazard Analysis and Risk-Based Preventive Controls (HARPC). Now, food processors are mandated to document all potential product risks, including naturally occurring hazards.
In its guidance report, a warning is made towards bacterial pathogens causing resident contamination in the processing facility. Pathogens can become established in a harborage site, an area in the equipment that enables the accumulation of dust residues and permits the growth of microorganisms.
To prevent transient bacterial pathogens from becoming resident strains, proper equipment design, sanitation controls, and management processes are key, particularly in enclosed bag emptying systems where the risk of microbes build-up is increased.
The report goes on to discuss one of the most pressing challenges facing the food industry today: the control of ingredient-related allergen contamination. Approximately one in 10 U.S. citizens now suffer from at least one allergy, the key culprits in powder form being gluten found in flour, as well as dairy powders and specific spices.
For smaller- to medium-sized producers, segregating the various processes that handle raw ingredients containing allergens might not be possible, and so rigorous dust control and washdown methods should be deployed. It is advisable for machinery to follow industry best practice in terms of hygienic design and feature good accessibility to the various components that are in contact with dust particles.
Minimizing Waste, Maximizing Yield
In addition to health and safety, the conventional method of discharging and conveying bulk ingredients raises concerns regarding efficiency and waste. Prior attempts to automate the process have led to remnants lingering behind and sticking to discarded bags, thus defeating the cost-saving benefits of the machine.
Another issue was the rough tearing of bag covers, resulting in particles contaminating the raw products that were being fed into manufacturing systems, leading to costly rejects. Ingredients and materials are expensive, so to offset the cost of investment in automated machinery, maximizing yield is paramount.
“If dust emissions are contained and controlled at this critical point in the process, non-value adding housekeeping tasks can be minimized,” said Navam Jagan, OEM Luxme International. “Productivity isn’t hindered by dust build-up and breakdowns and operator interventions are reduced, ultimately leading to a more efficient and cost-effective operation throughout the entire production line.
“The prevalence of dust emissions at the bag emptying station intensifies the health and safety risks in the area, as well as contamination and waste, so it is essential that bag slitter manufacturers work with upstream and downstream equipment suppliers to provide innovative new solutions to tackle these issues.”
All-in-One Solution: Automatic Bag Slitters
Automated bag slitters eliminate or reduce operator exposure to a dusty environment. The efficiency benefits delivered by compact all-in-one systems that integrate conveying, slitting, emptying, dust filtration, and empty bag compaction provide a cost-effective replacement for redundant manual dump stations.
In terms of the operation, bags are manually placed on the slitter in-feed and conveyed to the slitting chamber where blades move around the bag, cutting three sides and opening it into a single long sheet. The bag is inverted for gravity discharge of the product.
Navam points out that specialized equipment is now available that is USDA-approved and therefore ideal for handling bulk solids in a food manufacturing environment. “An example is Luxme’s automatic bag slitter Minilux food grade, specially designed to open bags in an enclosed, dust-free, sanitary environment, for items such as dairy products, infant formulas, spices, cake mix, cocoa powder, etc.,” he said.
Hygienic design includes multiple access points for easy cleanability to ensure allergens and pathogens don’t make their way into the food chain. To comply with food safety legislation, this type of bag slitter utilizes FDA-approved components to facilitate the safe processing of food products and is designed to slit and open five to six bags per minute, weighing up to 25kg.
Automating the bag opening bulk powder and ingredients operation reduces costs and waste, making the production more economically competitive. However, there are still risks regarding remnants of product sticking to the walls of the machinery and dust filling the valves of discarded empty bags, which offsets the advantage of cost savings.
To mitigate this problem, a highly recommended optional upgrade is available that automatically extrudes empty bags into an integral secondary product recovery tumbler. Tests have shown that recovery tumblers – which open, rotate, and tumble empty bags numerous times to release any remaining product – ensure 99.98% efficiency depending upon the free-flowing characteristics of the product.
As with all bulk handling applications, it is important to take every stage of the process into consideration. If a bag discharge station is required within the facility, automated bulk handling systems offer a safer, more sanitary environment for operators and deliver higher yield production.
Navam Jagan, B.Sc (Hons), P.Eng, is president, Luxme International Ltd. For more information, visit www.luxme.com.
Image 1: Horizontally rotating circular blades
Image 2: Minilux food grade automatic bag slitter
Image 3: Secondary product recovery tumbler
Image 4: Woven bag after slitting