Food production insights

• Current good manufacturing practice regulations are crucial in ensuring the safety of the final product in various industries, particularly in food production.
• CO2 and N2 are commonly used in food production and present unique risks and considerations when designing these facilities.

Industrial facilities encompass various range of sectors including food, beverage, life sciences and advanced technology manufacturing. In this second installment, readers will understand more about both the generic principles and specific aspects of the Indoor Air Quality – Indoor Environmental Quality (IAQ-IEQ) design for food production and beverage bottling industries.

The Food and Drug Administration (FDA) has specific current good manufacturing practice (cGMP) regulations pertaining to various types of facilities. The rules may differ significantly for each particular industry, but the fundamental priority for each one is to ensure that the final product is safe for consumption.

As professional engineers, it is imperative to not only consider the cGMP regulations, but to also ensure the safety of personnel in the working environment. Additionally, it is necessary to ensure that the natural environment is not adversely affected and that the design meets general energy efficiency and other sustainability goals, such as water use efficiency, whether mandated or exempted.

Design guidelines for food production

With regard to the food industry, there are a specific set of cGMP regulations under Title 21 Code of Federal Regulations Part 117: Current Good Manufacturing Practice, Hazard Analysis and Risk-Based Preventive Controls for Human Food, along with requirements for hazard analysis and risk-based preventive controls that were issued as part of the implementation of the FDA Food Safety Modernization Act.

Covered facilities are required to implement a written food safety plan that includes both hazard analysis and preventive controls.

The first step in any hazard analysis is hazard identification, which must consider known or reasonably foreseeable biological, chemical and physical hazards. These hazards could be present because they occur naturally, are unintentionally introduced or are intentionally introduced for economic gain. If the hazard analysis reveals one or more hazards that require preventive control, the facility must have and implement written preventive controls for the identified hazards.

Facilities have the flexibility to tailor preventive controls to address specific hazards that occur in the products they manufacture. There is a plethora of preventive controls in the regulations on all aspects of the facility’s canned operations.

Figure 1: This diagram shows a typical food or beverage manufacturing facility and how transition zones separate high-care (high and medium hygiene areas) from basic hygiene and non-good manufacturing practices (GMP) areas. Courtesy: Barry-Wehmiller Design Group

Some of the facility construction specific rules include the following, according to the Code of Federal Regulations Title 21, CFR 111, 117, 211, 507 and 600:

• Water supply: The utility water supply must be adequate for the operations intended, including production and cleaning and must be derived from an acceptable source. Any water that contacts regulated processes must be safe and of adequate sanitary quality
• Plumbing: The plumbing system must be of adequate size and design and adequately installed and maintained to:
  • Carry adequate quantities of water to required locations throughout the plant
  • Properly convey sewage and liquid disposable waste from the plant
  • Avoid constituting a source of contamination to food, water supplies, equipment or utensils that might create an unsanitary condition
  • Provide adequate floor drainage in all areas where floors are subject to flooding-type cleaning or where normal operations release or discharge water or other liquid waste on the floor
  • Ensure that there is no backflow from, or cross-connection between, piping systems that discharge wastewater or sewage and piping systems that carry water for the food manufacturing process
• Sewage disposal: Sewage must be disposed of into an adequate municipal or private sewage system or disposed of through other acceptable means
• Toilet facilities: Each plant must provide employees with adequate, readily accessible toilet facilities. Toilet facilities must be kept clean and must not be a potential source of contamination of food, food-contact surfaces or food-packaging materials
• Hand-washing facilities: Each plant must provide hand-washing facilities designed to ensure that an employee’s hands are not a source of contamination for food, food-contact surfaces or food-packaging materials, by providing facilities that are adequate, convenient and furnish running water at a suitable temperature
• Lighting: Provide adequate lighting in hand-washing areas, dressing and locker rooms, toilet rooms and in all areas where food is examined, manufactured, processed, packed or held and where equipment or utensils are cleaned. Additionally, provide shatter-resistant light bulbs, fixtures, skylights or other glass suspended over exposed food in any step of preparation or otherwise protect against food contamination in case of glass breakage
• Ventilation: The plant must provide adequate ventilation or control equipment to minimize dust, odors and vapors (including steam and noxious fumes) in areas where they may cause allergen cross-contamination or contaminate food. Locate and operate fans and other air-blowing equipment in a manner that minimizes the potential for allergen cross-contact and for contaminating food, food-packaging materials and food-contact surfaces

CO2 in food production and beverage bottling

A particular concern in many food production and bottling facilities is the high concentration of introduced carbon dioxide (CO2) in the production process. CO2 on its own is a common, inert compound in ambient air. However, in industrial facilities it can become an asphyxiation hazard if it becomes too concentrated in low-lying spaces or confined spaces. Occupational Safety and Health Administration has established a carbon dioxide acceptable permissible exposure limit (PEL) of 5,000 parts per million (ppm) for an eight-hour day. The American Conference of Governmental Industrial Hygienists (ACGIH) also recommends a 15-minute short term exposure limit (STEL) of 30,000 ppm. Common sources and applications include following:

• Dry ice: One common source of CO2 is dry ice. Dry ice is simply CO2 in a solid-state. In open-air, it will rapidly vaporize into CO2 Therefore, exceeding localized 5,000 ppm PEL and 30,000 ppm STEL concentrations are likely where industrial quantities of dry ice are used.

• Carbonated beverages packaging: When carbonated beverages are bottled or canned, the liquid beverage is added to the containers and then high-pressure CO2 is forced into the liquid. Leakage or spillage to some extent always occurs and without adequate ventilation, the excess CO2 can get into the workspace where workers are situated. Low points can trap very high levels of concentrated carbon dioxide well in excess of the 5,000 ppm eight-hour PEL and even the 30,000 ppm 15-minute STEL depending on the size of the bottling operation.

• Flash freezing: Another situation is where liquid CO2 is used to flash freeze foods. Again, the liquid easily flashes into gas and can spread into the worker’s breathing zone and exceed the safe limits, particularly in confined low points.

Nitrogen in food production

Another gas that is regularly used in food processing is liquified nitrogen. It is typically used to flash freeze perishables and is also used to “inert” the atmosphere by intentionally removing the oxygen to prevent certain pasteurized liquids that are packaged and/or stored at room temperature from spoiling. Gaseous nitrogen, unlike carbon dioxide, is lighter than air and will disperse throughout a given confined space. Cold nitrogen vapor flashing from liquid is heavier than air and will tend to settle in low points. Depending on the volume of liquid nitrogen released in a confined space, it can easily displace all the air in a room and cause an asphyxiation hazard.

Whenever these gases are used in the food production process, high and low gas detection systems and rapid exhaust and fresh air makeup are required. For slow, steady release in gas form, general ventilation rates may be adequate to dilute and maintain acceptable PEL levels.

However, in the event of a rapid release of liquified gases that will flash very quickly or large quantities of open-air dry ice, the flashed or vaporized gas will expand tremendously in volume and can fill up a confined space displacing all breathing air.

To mitigate these types of emergencies, a control system is required with oxygen sensors and an alarm sequence on rapid drop of oxygen below a certain threshold, which activates a dedicated room exhaust and rapid partially conditioned fresh air makeup. In this circumstance, the primary concern is for occupants to safely breathe, so typically the makeup air is heated in the winter above freezing, but not air conditioned in the summer.

The key points presented in this article should serve as a good starting point in understanding some of the unique design considerations for IAQ-IEQ for food and beverage facilities.

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