Dust Collection for the Bakery Industry

Baking almost always involves some type of flour (all-purpose wheat, whole wheat, cake flour, pastry flour, and specialty flours such as spelt, cornmeal, rye and einkorn). But flour isn’t the only problem in a bakery. Depending on the recipe, bakeries may also contend with other types of food dust, as well. These may include: 

• Sugar (white or brown granulated, powdered, confectionary)
• Starches (cornstarch, tapioca powder, rice flour, xanthan gum, potato starch)
• Spices and flavorings (salt, cocoa, cinnamon, turmeric, cloves, nutmeg, ginger, mace, etc.)
• Leavening agents (baking powder, baking soda, yeast)
• Powdered milk, powdered eggs
• Food additives, preservatives and emulsifiers 
• Nuts and seeds 

Dust is an issue for virtually all commercial bakeries, no matter what they are making. Baked goods made at commercial bakeries may include: 

• Breads, rolls and biscuits 
• Cakes and muffins
• Pastries and cookies
• Pies 
• Crackers 

• Food safety: Bakers must consider two important elements of food safety when it comes to dust control: microbial growth and cross-contamination. Uncontrolled baking dust creates an environment where food dust can build up on surfaces and inside equipment. This creates an ideal breeding ground for many different kinds of microbes, including yeasts, molds and bacteria—especially in the warm, moist environment of a bakery. Many dangerous molds thrive on grain products such as corn and wheat. Flour dust may also harbor bacterial microbes such as salmonellosis and Enterobacter sakazakii. Bakers must also have systems in place to prevent cross-contamination between different bakery products. This is especially important when working with ingredients that are common food allergens, such as wheat (gluten), nuts (peanuts, tree nuts, and other types), eggs (eggshell dust or dehydrated egg products), dairy (dehydrated milk), and sesame. Spices and food additives may also cause serious allergic reactions in some people. 
• Food quality and presentation: Beyond the allergen concern, contamination with excess dust may impact food quality, flavor and desirability. It is especially important to control dust during the packaging process, including box filling and bag filling; excess dust in or on the packaged product is highly undesirable from a consumer perspective.
• Worker health and safety: Exposure to grain dust in the levels encountered in a commercial bakery can be hazardous to worker health. Workers continuously exposed to raw flour may develop a condition known as “baker’s lung” (or baker’s asthma or baker’s allergy), which presents as wheezing, coughing, chest tightness and eye and nose irritation. It is common for bakers to develop allergic reactions and sensitivities to grain dust over time. Many spices and additives are also considered to be dangerous when inhaled, and some may cause skin or eye irritation. Cinnamon, for example, contains a volatile oil that can cause asthma and skin and eye irritation; it is often processed in special rooms due to the exposure hazards. And uncontrolled dust of any type is a housekeeping and sanitation consideration. Dust build-up on walking/working surfaces can create slip-and-fall hazards for workers.
• Employee retention: A dust control solution can help companies create better working conditions that improve retention of experienced bakers and line workers. Reducing exposure to nuisance dusts makes the facility more pleasant to work in for everyone.

• Combustible dusts: Bakeries have special considerations when it comes to combustible dusts. Baking dust falls under NFPA 61, Standard for the Prevention of Fires and Dust Explosions in Agriculture and Food Processing, as well as NFPA 654, Standard for the Prevention of Fire and Dust Explosions from the Manufacturing, Processing and Handling of Combustible Particulate Solids. Combustible dusts are regulated under OSHA’s General Duty Clause (Section 5(a)(1)) with additional requirements under the Hazardous Locations (§1910.307), Hazard Communication (§1910.1200) and Housekeeping (§1910.22) standards. OSHA’s Combustible Dust National Emphasis Program (NEP) outlines policies and procedures for inspecting workplaces that create or handle combustible dusts. In addition, commercial bakeries must comply with OSHA 1910.263, which sets standards for design and operation of flour-handling systems, dumpbins, blenders, mixers, sifters and other bakery equipment to reduce explosion risks. Dust collection systems for food processing dusts must also meet NFPA 68, Standard of Explosion Protection by Deflagration Venting, and NFPA 69, Standard on Explosion Prevention Systems. 
• Food Safety: The Food Safety Modernization Act requires all companies in the food industry, including commercial bakeries, to have controls in place to reduce cross-contamination of food allergens and prevent microbial contamination. These include preventative controls (such as control of airborne dust, prevention of dust build-up on surfaces and in production lines, and sanitation of equipment and surfaces) as well as processes for food safety evaluation, problem identification and mitigation, and food recalls. Companies that do not comply with FDA food safety requirements are at risk of large fines or even suspension of their registration. 
• Nuisance dusts: Many food processing dusts fall under the OSHA definition of “nuisance dusts,” which are regulated under the general particulate matter concentration limits set by OSHA. The general limit for “Particulates Not Otherwise Regulated” (PNOLs) is 15 mg/m3 (8-hour TWA limit) for total particulate and 5 mg/m3 for respirable particulates. Employers must also follow general Housekeeping standards (OSHA 1910.22, Walking-Working Surfaces) to prevent accumulation of dust on surfaces.
• Flavoring Substances: OSHA has not developed specific Permissible Exposure Limits (PELs) for most chemicals used in baking and food processing. However, because of the safety concerns for workers exposed to fine respirable dusts and volatile organic compounds (VOCs) produced by many chemical flavorings and additives, OSHA has issued a Safety and Health Information Bulletin titled Occupational Exposure to Flavoring Substances: Health Effects and Hazard Control. While these recommendations are not binding, OSHA strongly suggests that companies where workers are exposed to potentially dangerous food additives put engineering controls in place, including appropriate ventilation, isolation of processes (such as batch mixing) that produce dust or fumes, and access control for areas where these processes occur.

• Dust collection and filtration: The volume of dust created in a commercial bakery will generally require a specialized dust collection system. A cartridge-style dust collector is a practical and efficient choice for bakeries. Cartridge-style dust collectors have a small footprint per CFM compared to other styles of dust collectors, such as baghouse. They also have a wider range of filter options to collect even very fine baking dust or fumes created by additives and flavorings. 
• Enclosure/source capture: Many baking processes (e.g., batch mixers, sifter, dumpbins, etc.) are easily enclosed to contain dust for source capture. If the process cannot be enclosed, it is possible to create a custom hood to draw dust away from the production line as it is created. Positive and negative pressure zones can also be used to prevent dust from earlier processes and conveyor systems from propagating into areas where baked goods are finished and packaged. 
• Combustion mitigation: Special care must be taken when collecting flour and other combustible dusts to minimize the risks of an explosion inside the dust collector. The dust collector should be equipped with a deflagration system to prevent pressure waves from propagating back into the facility if an explosion should occur.
• Dust collector location: In most cases, the dust collector for a commercial bakery will be located outside and will vent filtered air to the outside. This prevents re-contamination of food and food packaging when the filters are changed or the dust collector bin is emptied. 
• Makeup air and filtration: Because air is usually vented outside, a makeup air system will also be required to maintain the right air pressure inside the facility. HEPA filtration in the HVAC or makeup air system will ensure that air that enters the facility is clean and does not introduce any contamination into baking or packaging lines.
• Filter media selection: Selecting the right filter for the dust collection system is also very important for commercial baking dust. Many flours, sugars and other food dusts are hygroscopic, meaning they readily absorb moisture from the air. In a humid environment, these dusts may cake or form a crust on filters. A washable filter media can extend filter life considerably in these situations.