The Growing Challenge of Safe Water for Use in Food Processing Operations
By Larry Keener, CFS, PA, PCQI
An old adage of oenophiles and epicureans says: “If the wine isn’t fit for drinking, then it’s not fit for use in cooking.” The same is true for water. If your water supply is of poor quality, then it is a reasonable assumption that its use in food processing would have an adverse effect on the organoleptic properties of that food or, more importantly, on its safety. When a potable water supply, drinking water, contains lead, manganese, pharmaceutical compounds, pesticides, radionuclides, or “forever chemicals” (such as per- and polyfluoroalkyl substances or PFAS), then it should probably be prohibited from use in the production of human food, but the reality on the ground may be different.
Increasingly, the water supply for many municipalities and food processing operations is at risk of environmental contaminants both natural and human-made. The spectacular and now notorious failures of the municipal water district in Flint, MI, which led to tainted drinking water that contained lead and other toxins, offer an example of the magnitude and extent of the public health problems that may be associated with unsafe drinking water. For about the last 50 years, there have been multiplying reports of PFAS and their related compounds in the environment and in drinking water. PFAS compose a family of human-made chemicals found in a wide range of products used by consumers and industry. There are nearly 5,000 types of PFAS, some of which have been more widely used and studied than others. Many PFAS are resistant to grease, oil, water, and heat. For this reason, beginning in the 1940s, PFAS have been used in a variety of applications, including in stain- and water-resistant fabrics and carpeting, cleaning products, paints, and firefighting foams. In addition, certain PFAS are authorized by the U.S. Food and Drug Administration for limited use in cookware, food packaging, and food processing.
The widespread use of PFAS and their ability to remain intact in the environment means that over time, PFAS can result in increasing levels of environmental contamination. Accumulation of certain PFAS has also been shown to occur in humans and animals. While the science surrounding potential health effects of PFAS is developing, current evidence suggests that the bioaccumulation of certain PFAS may cause serious health conditions.
What Is the Risk of PFAS?
There doesn’t appear to be consensus among toxicologists as to the risk these compounds pose for public health. In 2019, the U.S. House of Representatives introduced the PFAS Action Act (H.R.535). The legislation would require that the administrator of the U.S. Environmental Protection Agency (EPA) designate PFAS as hazardous substances under the Comprehensive Environmental Response, Compensation, and Liability Act of 1980. “PFAS are an urgent threat to public health. They are toxic, persistent, and being found in the environment across the country. These ‘forever chemicals’ have long been linked with adverse health effects including cancer, immune system effects, infertility, impaired child development, high cholesterol, and thyroid disease.”
Access to safe water is recognized by the United Nations as a fundamental human right. While more than 60,000 chemicals are in use in the U.S., thousands of which have been studied by government and independent scientists, only 97 chemicals or chemical groups and 12 microbial contaminants are currently regulated by the Safe Drinking Water Act of 1974. Government scientists generally agree that many chemicals commonly found in drinking water pose health risks at lower concentrations than previously thought, and millions of Americans become sick each year from drinking contaminated water. A safe supply of water is as critical to the food industry as it is to sustaining life on this planet.
Water Use in Food Processing
Water is widely used within the food processing industry. It is pumped, dripped, sprayed, and steamed throughout food processing establishments around the world. It is used for washing, cutting, conveying, and for fluming fruits and vegetables. Water is used to lubricate food contact surfaces and parts of food processing equipment. It is added to hams, candy, and confectionary products. Water is used in abundance in its gaseous, solid, and liquid states. Water is captured, stored, recycled, and reused. It is used as a processing aid, an indirect additive, and a food ingredient. In fact, water is frequently the primary ingredient in a wide variety of processed foods and beverages. For example, in a report on water usage in food processing, the production of one ton of tomato paste required 351 gallons of water; a ton of canned tomatoes required 751 gallons; and a ton of canned olives nearly 4,500 gallons.4 A typical tomato conversion plant processes about 250 tons of raw tomatoes per hour, and these facilities operate on 24-hour production cycles. Thus, the production of canned tomatoes would use some 4.5 million gallons of water per each 24 hours of production. That equals the total volume contained by six Olympic-size swimming pools. Fortunately, much of this water is captured and reused.
Developing and implementing a comprehensive water-monitoring program, particularly in light of the unique relationship between food processors and their water suppliers, and current official information about waterborne contaminants, are fundamental and essential elements of an effective food safety program. Risk assessment is paramount in achieving food safety.
Impact of PFAS on Water Safety
A recent report by the Environmental Working Group (EWG) cites the latest statistics on PFAS’ reach into everyday life: Drinking water systems serving an estimated 19 million people, in at least 610 locations across 43 states, are known to be contaminated with one or more of the thousands of known PFAS. Another study from the EWG reports PFAS contamination of drinking water or groundwater in almost 1,400 sites in 49 states. California, Kentucky, Michigan, New Jersey, and New York had numerous PFAS-contaminated sites. The EWG reported that of tap water samples from 44 locations in 31 states and the District of Columbia, only one location had no detectable PFAS, and only two other locations had PFAS below the level that independent studies show pose risks to human health. Some of the highest PFAS levels detected were in water samples from major metropolitan areas, including Miami, New Orleans, the northern New Jersey suburbs of New York City, and Philadelphia. In the 43 samples where PFAS were detected, the total level varied from less than 1 ppt in Seattle and Tuscaloosa, AL, to almost 186 ppt in Brunswick County, NC.
EPA has established a health advisory level of 70 ppt of combined PFAS in drinking water due to links to cancer, developmental effects, liver damage, and thyroid issues. Recently, the federal Agency for Toxic Substances and Disease Registry proposed a more aggressive recommendation of 7 ppt for perfluorooctane sulfonate (PFOS) and 11 ppt for perfluorooctane carboxylate (PFOA) in drinking water, the most notorious PFAS known. Currently, the U.S. Centers for Disease Control and Prevention (CDC) is using perfluorinated chemicals and EPA is using PFOS to collectively describe PFOA and PFOS and other chemicals in this group.
These compounds have been phased out under pressure from EPA, but they persist in drinking water, people, and the environment. In EWG’s report, PFOA was detected in 30 of 44 samples, and PFOS was found in 34 samples. These two compounds represented approximately a quarter of the total PFAS levels in each sample.
Current options for drinking water treatment technologies to remove PFAS include granular activated carbon (GAC), ion exchange, and reverse osmosis. GAC is the most common, with many water treatment facilities already using it to remove other contaminants. Reverse osmosis is the most effective technology, but it is also the most expensive. Ion exchange is a newer technology for PFAS removal.
Are these PFAS risks considered in your calculations when assessing water for use in your food products? Has your water supplier informed you of the presence of these chemicals in their supply sources? Are there measures provided that will reduce the threat to acceptable public health levels?
Strategies for Monitoring PFAS
The first steps in setting up a monitoring program require detailed knowledge of your products and intended consumers. You should also seek to obtain detailed information regarding the origins and mode of distribution of your water supply.
Understanding the product and the intended consumer is fundamental to the development of a coherent water monitoring program. Is the food treated or otherwise processed so as to be lethal to pathogenic organisms? Or is the food a product that lacks a kill step and is therefore capable of supporting microbial pathogens? Are infants, small children, and cancer patients the intended users of the food? Clearly, the answers to these questions will ultimately dictate the scope and intensity of the monitoring program. Detailed knowledge about the water supply is also critical to understanding the risk that it may represent for your products. Is the water derived from a surface or groundwater source? Is the water from privately owned wells or from a public water treatment facility? What type of treatment regimen does the water supplier use? What chemical additives are used in the treatment process? It is also important to know the types of testing performed on the water supply and the availability of the results.
For example, a food processor operating a plant within metropolitan Seattle should know that the water supplied by the public utility is derived from both surface and groundwater (wells) sources, but that the primary supply is from surface water sources. It is also of value to the processor to know that coagulants, flocculants, corrosion-control minerals, and fluoride are added to the water, and that ozonation and chlorination are used as primary modes of disinfecting. The public utility tests the supply at the treatment works in accordance with EPA requirements. Testing includes microbiological parameters, disinfection by-products, and levels of iron, manganese, sulfate, lead, copper, and nitrate. Seattle, under its Unregulated Contaminants Monitoring Rule 4.0 (UCMR 4), also tests the water supply for an assortment of other unregulated compounds, including dichloroacetic acid, trichloroacetic acid, manganese, and bromodichloroacetic acid. The UCMR 4 outlines a schedule for the testing of contaminants that do not have EPA-established, health-based standards.
In October 2018, the Seattle Public Utility (SPU) tested water from both the Tolt and Cedar Rivers for 14 types of PFAS. They reported all samples tested negative. However, and it is noteworthy, the 2018 water quality report does not indicate that the utility tested its wells (groundwater sources) for PFAS contamination. The wells are located in Burien, a community adjacent to the city’s main airport and therefore at high risk for PFAS contamination. Testing results are summarized in the SPU annual report. It is also possible to work with the utility to obtain these data more frequently. While the utility’s annual report does not show PFAS testing of its water wells in 2018, personal correspondence received from the utility (March 24, 2020) confirms that the water wells were tested and that one of its three wells tested positive for PFAS. SPU reported that its Boulevard Park well tested positive for 5 of the 14 PFAS included in the assay. All test results were below the safety limits established by EPA (Table 1).
In addition to the aforementioned considerations, it is advisable to seek out information about the water distribution system. For example, it is important to have some idea of the system’s age and materials of construction. Some utilities are reported to still have wire-wound wooden pipes used in their water delivery systems. It is also important to know whether wastewater lines are placed in the same subterranean street beds alongside potable water lines and whether the potable water system is adequately pressurized to prevent cross-contamination in the event of a ruptured sewer line. Historically, significant portions of waterborne disease outbreaks reported by CDC are caused by distribution system deficiencies. Between 1971 and 1994, approximately 53 waterborne disease outbreaks reported were associated with failures of the distribution system.
If the potable water supply is sourced from privately owned wells, a hydrologist should be consulted to assess the physical condition of the well and its surrounding environment. The hydrologist might also be asked to provide a view to the likely future performance of the well. The well’s water should also be broadly tested for both chemical and microbial contaminants. Radioactive compounds should be included in the initial work to commission wells as sources of drinking water. A chemical assay should be completed annually and microbiological testing done quarterly.
Product information coupled with information about the water supply will factor heavily in determining what conditions or attributes of the water supply require monitoring. First, before beginning the development of a monitoring program—whether the monitoring is of a privately owned well or a public water source—it is imperative that the program include both the “supply as it is delivered to the factory” and “as it is contained within the factory’s plumbing.” For effective monitoring, these elements should be viewed as separate and distinct delivery streams. The benefit of this separation is the illumination of the sources of contaminants. In fact, contamination may not always be associated with the water supply as delivered; rather, the contamination may result from cross-connections between potable and nonpotable sources within the factory’s plumbing.
Trust Your Water Supplier, but Verify
Many leading food and beverage companies routinely receive and review water quality reports provided by their supplier. This is the first element of a program for monitoring the water supply as it is delivered to the factory. The majority of these companies also make arrangements with the supplier to provide these data on a frequency that exceeds the normal distribution. It is also customary to have central office staff (microbiologists, engineers, environmental specialists, and the food safety officer) involvement with this review process. Specialist involvement is key to the success of this type of monitoring arrangement.
Companies also periodically test the water supply to confirm the information reported by the supplier. The testing program typically includes assays for both chemical and biological contaminants. The interval for receiving the supplier’s testing data and of confirmatory testing should be a function of the types of products being produced at a given location. As a rule, a comprehensive evaluation of the inbound water supply should be completed annually. Monitoring for chemical contaminants should include arsenic, barium, barium 140, cadmium, cesium 137, chromium, copper, iodine 131, iron, lead, magnesium, manganese, mercury, nitrate, pesticides, PFAS, polyaromatic hydrocarbons, volatile organic compounds (VOCs), and zinc. PFAS have emerged as an important new class of drinking-water contaminants that should not be omitted from your testing program. While not the focus of this article, testing to monitor the microbiological status of the inbound water supply should also be performed.
Monitoring In-Plant Water
Monitoring the water supply as it is contained within the plant’s plumbing is also an important element of a comprehensive program to assess risks associated with the potable water supply. Food processing plants, generally speaking, are an exceedingly complex array of pipes, valves, conduits, tanks, and kettles. This network may transport or contain raw materials, intermediate products, finished products, or both potable and nonpotable sources of water. The piping network may also contain raw sewage or process waste. Owing to these complexities, there is always the potential risk of cross-connection between these various elements and the subsequent contamination of the water supply with dangerous foreign substances. Contamination may arise as a result of conditions or practices within the confines of the factory, which have no relationship with the water as it is delivered. For these reasons, it is important to develop a reliable plan to monitor water-handling and use practices within the factory.
The first step in establishing the plan is a physical audit of the plant’s potable water-handling system. The audit should include a review of the plant’s most current plumbing plan or other documents that provide details related to the installation and maintenance of the plumbing system. The audit should provide confirmation of the plumbing plan’s integrity. The auditor should also seek to identify areas of the plan that may be at risk of cross-connection or other forms of contamination. For example, the audit should identify points where there is the potential for back siphonage (flowing back of used, contaminated, or polluted water from a plumbing fixture or vessel into a potable water supply due to negative pressure in the pipe) of wastewater or other impurities into the potable supply. Once the audit has been completed and the company is satisfied that the system is safe, then it is appropriate to develop a monitoring strategy.
Monitoring the integrity of a factory’s plumbing, in a majority of cases, should focus on tracking the microbiological status of the water supply. A small change in the baseline microbiological data may indicate contamination. As always, the frequency of testing should be a function of risk, the sensitivity of the product, and its manufacturing processes. As a general rule, the supply should be tested quarterly. Testing must always be initiated concurrent with any work, maintenance activities, or repairs that involve opening the plant’s water-handling and distribution systems.
In a majority of processing operations, the risk of contaminating the water supply with chemicals within the plumbing system is remote. However, some processors collect and store significant quantities of water. In addition to storage tanks or cisterns, the storage systems are usually fitted with in-line filters, traps, or other devices. Microbiological testing should be completed in conjunction with service or replacement of these devices. Chemical testing must also be completed when the storage tanks or cisterns are taken off-line for refurbishing or repairs. It is absolutely imperative that chemical testing of water from these tanks is completed before they are placed back into service. The testing should confirm that all repairs and treatments have been properly applied. The analysis should consider VOCs, heavy metals, pesticide residues, and any other compounds that might be associated with a particular treatment regimen.
It is clear that water is one of the most important and widely used substances in the food processing industry. It is also clear why, in terms of food safety, water is one of the least scrutinized of all materials used in food processing. The relationship between food processors and their water suppliers is truly unique within the industry. The relationship is unlike the relationship with other ingredient and raw materials suppliers in that the end user can’t reject nonconforming shipments or sever business relations with vendors based on poor performance. The processor and supplier don’t agree to a specification. The water emanating from the tap is precisely what is purchased. The water suppliers truly have a captive audience.
As a result, the processing industry needs to establish comprehensive programs that monitor the public health status of its water supply. EPA and CDC data suggest that waterborne disease outbreaks have been reported in a majority of states. Moreover, in 1990, EPA’s Science Advisory Board cited drinking water contamination as one of the most important environmental risks and indicated that disease-causing microbial contaminants are probably the greatest remaining health-risk management challenges for drinking water suppliers. Because of the volumes of water used by the food processing industry, they too share this challenge. The industry is at risk.
For many processors, water-monitoring strategies can be an effective alternative to an expensive investment in water treatment equipment. A properly developed and implemented monitoring program can be an effective means of minimizing risk to the business and its consumers. The successful monitoring program is based on the following:
• Detailed knowledge of the product and how water is used in its production
• Knowledge of the intended consumer
• Knowledge of the water supply and its distribution system
• Forming a partnership with the water supplier
• Knowledge of water-handling and distribution practices within the factory
• Data, both historical and current, about the water supply
Armed with this information, a robust and reliable monitoring program can be developed that will enable the processor to make reasonable decisions about the business, the products, and the consumers. In a crisis involving the processor’s products, neither the water supplier nor any other public health official will be called upon to make these tough business decisions.
In the midst of the greatest public health crisis in a century, the COVID- 19 pandemic, we are told to frequently wash our hands. This recommendation from CDC and other public health agencies is seen as the most effective aegis against the spread of this deadly contagion. We are advised that this simple, uncomplicated act of using clean water and soap for 20 seconds to scrub one’s hands is the best weapon in the fight against the virus. But the facts are, this most simple of preventive measures is not an option in the absence of clean water. At the onset of the pandemic, in the U.S., the federal government warned water companies not to shut off water to those who were delinquent in making payments and not to deprive citizens of access to water in the time of a great public health emergency. Evidence confirms that our nation’s aging drinking water infrastructure is contributing greatly to an increase in public health-related issues. Lead, Legionella, and now PFAS are routinely reported in the nation’s drinking water supply. Flint, MI, nestled safely amid the planet’s most abundant source of fresh water, may just be the leading indicator of the nation’s next great epidemic. Those pristine waters issuing from a silent spring may not be so safe after all.
Larry Keener, CFS, PA, PCQI, is the owner and general manager of International Product Safety Consultants. He is also a member of the Food Safety Magazine editorial advisory board. He can be reached via email at firstname.lastname@example.org.
8. www.atsdr.cdc.gov/toxfaqs/tf.asp?id=1116& tid=237.