Discussion on the Prevention of Pollutants from Compressed Air in Food and Beverage Field
According to statistics from the U.S. Department of Agriculture, there are more than 30,000 food and beverage processing plants in the United States, employing more than 1.5 million workers, and each of these plants uses a variety of processing techniques for the production of agricultural raw materials for consumer food and beverage products.
In these processes, the application of industrial compressed air plays an important role. Processing plants use compressed air systems to support the sorting, cutting, forming and packaging of food and beverage products. The company also uses compressed air to clean containers before filling, and to blow away particles when cleaning food and equipment.
The compressed air system used in food and beverage production plants includes air compressor dryers, filters, system pipes, fittings, seals, air storage devices, valves, pumps, cylinders, and motors.
The system includes several water, oil and particulate removal stages. These different stages include water separators, absorption dryers, refrigeration dryers, oil vapor removal filters, coalescing filters, adsorption filters, dust removal filters and sterile filters. Each moisture and particulate matter removal stage must meet or exceed the performance standards of the Federal Drug Administration (FDA) and the International Standards Organization (ISO) [2]. In addition to these standards, there are the British Compressed Air Association (BCAS), the British Retail Federation (BRC) and the Safe and Quality Food Association (SQF). The Canadian Food Safety Enhancement Program (FSEP) has also issued standards or minimum standards for monitoring compressed air quality. Good practice [3].
Although system requirements are different, food and beverage processing applications either use contact compressed air systems or non-contact high-risk compressed air systems. The contact type compressed air system makes the compressed air directly contact the food. Although non-contact high-risk compressed air systems do not allow compressed air to directly contact food, these systems produce materials that directly contact food, such as packaging. The non-contact compressed air system includes control valves, air motors and other equipment, but does not directly contact food or packaging.
The top priority of the health room in food and beverage processing
Due to the scale and complexity of the industry, if a product is recalled for health and safety due to the presence of pollutants or pathogens, it may cause almost irreparable financial losses and damage to the company’s reputation. Hazardous microbial communities can enter the system through raw food, air, water, processed surfaces, and the hands or clothes of factory employees. Microorganisms may form biofilms on slicing and cutting equipment, conveyors, storage tanks with pipes, filling and packaging machines, and heat exchangers.
A 2011 survey by the Grocery Manufacturers Association described the impact of the health and safety recall on the food and beverage processing industry. The loss of sales, downtime costs, product losses, and the effort spent in recalling products can be called astronomical figures.
All this shows that the safety and hygiene of compressed air systems for food and beverage production are of paramount importance. Any moisture in compressed air pipes, air motors or air compressors will promote the growth of fungi and microorganisms. Without proper sanitation procedures, compressed air systems can blow microbial contaminants, oil and other particulate matter onto food. Compressed air systems for food and beverage production also require dry air; any excess water blown onto the food creates opportunities for fungi or microorganisms to grow on the food.
The impact of laws and regulations on compressed air systems
All food and beverage processing operations must comply with the food safety standards contained in the Food and Drug Administration's Food Safety Modernization Act (FSMA). The Food Safety Administration covers the food supply chain from raw material production to consumer preparation, with a focus on preventing foodborne diseases. The implementation of the regulatory law has strengthened inspections of food processing plants, improved the ability to detect outbreaks of foodborne diseases, and increased the power to order food recalls. In addition, the Food Safety Administration has established a central database for tracking and tracing food safety information.
The "Food Safety Administration Human Food Prevention and Control Final Rules" require food facilities to develop a safety plan, including a hazard analysis and critical control point (HACCP) plan. In this case, the risk involves any point of contact between compressed air and food.
The HACCP plan analyzes biological, chemical, and physical hazards, describes products, and includes risk-based preventive controls to minimize or prevent identified hazards. Preventive control includes processes such as cooking, drying, refrigerating, filtering, freezing, pasteurization and acidification of food; defining methods to control cross-contact with allergens; describing hygienic processes The processing plant must monitor, correct, verify and record the application of preventive control [5].
Critical Control Points (CCPs) identify potential hazards that may occur. It also defines process controls to prevent the possibility of illness, injury or death caused by food-borne hazards. After determining the critical control points, members of the factory’s food safety team established and managed critical limits for determining process operating conditions.
In addition to determining CCPs, the HACCP plan also establishes a prerequisite plan for the implementation of good hygiene practices and training. The HACCP plan also specifies corrective actions if system failures lead to deviations from CCP critical limits, as well as verification measures to ensure compliance with the food safety plan.
The HACCP plan identifies risks in the compressed air system. The normal operation of the compressed air system for food and beverage processing draws ambient air into the system through the intake filter. Ambient air contains moisture, dirt, particles, oil, and other substances that make food poisonous when it comes in contact with food. One cubic meter of untreated compressed air contains about 180 million kinds of dirt particles, including water, gaseous hydrocarbons, pollen, trace metals and other pollutants [6].
Untreated compressed air also carries bacteria, which are easily spread through compressed air systems and come into contact with food. In addition to the possibility of direct contact with food, the bacteria carried in the compressed air system can also be attached to air compressors, air storage tanks, system pipes and accessories, and grow as microbial biofilms [7].
Since the compressed air system may directly contact food or food packaging, there may be a large number of CCPs opportunities and necessary procedures. For example, pneumatic knives and stirring tools are in direct contact with food and represent CCPs. The bagging system has indirect contact with food, and it also functions as CCPs.
Compressed air system risk management
HACCP plans and CCPs link risk identification and risk management through carefully planned design and preventive maintenance procedures. In the process of food and beverage processing, priority is given to consumer health and safety regulations and industry standards. As a design example based on industry benchmarks, the manufacturer recommends that compressed air systems need to install sterile filters wherever compressed air and food have indirect or direct contact.
Another key design point involves the use of desiccant to remove moisture from compressed air before the entire system is distributed. Because humid air can promote the growth of microorganisms and fungi in the air compressor and system piping in contact and non-contact high-risk compressed air systems. When the system is running, microorganisms and other contaminants will be blown onto the food or packaging [8].
The maintenance program considers the source of pollution and starts with the air flowing into the input end of the air compressor through the intake filter. Then the air compressor is carefully inspected, the pipeline distribution system is tested for pollutants, and the storage receiver is monitored and corrective measures are taken. Maintenance procedures also involve the performance and maintenance of separators and dryers. For example, a thorough maintenance check should confirm that the separator has removed a large amount of liquid and that the pressure dew point remains below the required critical temperature threshold.
Due to the need to remove particles in the system, the filter in the compressed air system can also be used as a key maintenance point. These solid particles may include bacterial spores that can survive under dry conditions, surrounding dust, pipe scale, residues of chemical cleaners, and other contaminants. Through the inspection, that is, according to the set threshold of 0.01 micron, when the DOP (dioctyl phthalate fog method test) efficiency is 99.99%, the solid contaminants, water and oil can be continuously removed from the compressed air through the coalescing filter Fog [7]
Preventive maintenance also includes regular monitoring of the compressed air used in all production processes. According to the definitions of the International Standards Organization, the British Compressed Air Association and the Institute of Safety and Quality Food, compressed air audits include analysis of particles, oil and microbial contaminants.
The "BCAS Food and Beverage Grade Compressed Air Best Practice Guide" stipulates that companies should test and verify the quality of compressed air in direct or indirect contact with food twice a year, or pay attention to details that may affect air quality during maintenance activities.
One point of prevention is better than extreme cure
Because of human intervention in food processing, it is very likely to be recalled. For example, in 2016, there were 905 recalls [10]. Data shows that most food recalls are voluntary, and the driving factor is the "reasonable probability" that the food may be contaminated.
Let us take a step back from the technical information and translate this topic into a language that we can all understand. The author had the honor to visit many different types of food processing facilities in North America, each of which made food safety a top priority. Although these facilities are subject to government inspections and supervision, they are all managed by dedicated quality control experts. They understand that when processing or packaging food, one point of prevention is better than ten points of treatment. After all, this cannot be ignored in the risk control of food consumed by humans and foodborne diseases.
references：
[1]“Food and Beverage Manufacturing."United States Department of Agriculture.2019.https://www.ers.usda.gov/topics/food-markets-prices/processingmarketing/manufacturing/
[2]“High Quality Compressor Air for the Food Industry."Parker Hannifin Corporation.2011.https: //www.parker.com/literature/Finite%20Airtek%20Filtration%20Division/PDF%20Static%20Files/Food%20&%20Beverage%20Market/67214_174004425_en%20NA.pdf
[3]“Compressed Air in the Food and Beverage Industry."Trace Analytics,Inc.2012.https:// www.airchecklab.com/resources/Compressed-Air-in-the-Foodand-Beverage-Industry.pdf
[4]“Capturing Recall Costs:Measuring and Recovering the Losses."Grocery Managers Association. 2011.https://www.gmaonline.org/forms/store/ProductFormPublic/capturing-recall-costs
[5“FSMA Final Rule for Preventive Controls for Human Food."U.S.Food and Drug Administration.2015.https://www.fda.gov/food/food-safety-modernizationact-fsma/fsma-final-rule-preventive-controls-human-food
[6]“Oil and Particulate Contamination."Sullair."https://www.amcompair.com/products/brochures/sullair_brochures/sulliar_filters.pdf
[7]Scott,Lee.“Reducing Contamination Risks of Compressed Air in Food Plants:Benchmarking Good Manufacturing Practices.";Parker Balston.November 2012.https://www. foodengineeringmag.com/ext/resources/WhitePapers/Compressed-Air-for-Food-GMPs.pdf
[8] Shanbhag,Nitin.Air Technology Group Hitachi America LTD.“Three Types of Food-Industry Compressed Air Systems.”Compressed Air Best Practices.http://www.hitachi-america.
us/ice/wecompressair/assets/hitachi-three-typesfoodindustry-compressed-air-systems.pdf
[9] BCAS Food and Beverage Grade Compressed Air–Best Practice Guideline.British Compressed Air Society.www.bcas.org.uk
[10] Ducharme,Jamie."You′re Not Imagining It:Food Recalls Are Getting More Common.Here’s Why"Time,January 2019.https://time.com/5504355/ food-recalls-more-common/
