August 2003: Volume 45, Number 8
Water Treatment in Food Service Establishments
by Tom Bruursema
The food service industry is well versed in performance-driven product standards. Ranging from icemakers to beverage dispensers, ware-washing equipment to commercial cooking, many ANSI/NSF standards are used and relied upon by equipment manufacturers, health departments, facility owners and operators for protection of public health in the food they prepare and serve. Similar needs and interests are also true with those products that treat the water supply used throughout these same establishments.
Water plays a very important role in the overall operation and performance of the food service establishment. It can impact equipment maintenance and life, the quality and safety of the food and beverage, and ultimately customer satisfaction. The underlying reasons for water treatment in food service are no different than those of individual residences. Wells and public water supplies cannot deliver a guarantee of public health safety, as demonstrated in widely publicized waterborne outbreaks that remain a threat to consumers. Further, wells and public water supplies often contain contaminants that can impact aesthetic qualities, i.e., taste and odor. For these reasons, food service establishments cannot risk a lack of attention to water quality, as it can have a direct and immediate impact on the success of their business.
Water treatment options
Treatment of the primary, total water supply is considered a first step but can be expensive and time/space consuming when treating for both health and aesthetic contaminants. As a result, whole-facility treatment is generally limited to those common contaminants that have the greatest overall impact, i.e., iron, scale and hardness. While not necessarily an impact on the consumer dining experience, frequency of maintenance and equipment wear can have a direct impact on operating expense. The end result required an analysis and balance between the expense of water treatment and the cost of maintenance, equipment repair and replacement.
Conversely, treatment at specific endpoints of water use in the food service establishment is more affordable and delivers a more obvious, direct impact on consumer satisfaction. The two areas that have historically been of greatest interest and impact are with ice production and fountain beverages. These products are consumed directly and comprised entirely of water, in the case of ice, and nearly so in the case of a fountain drink. Further, they’re mainstays in the vast majority of meals served, particularly in “fast food” establishments. Considering most of these drinks are served as a product of both the food service establishment and the beverage company, i.e., Coca-Cola, Pepsi and others, there’s more than one company impacted by the consumer satisfaction in the final product purchased. This creates an environment for joint cooperation between the food service owner/operator and the beverage company.
Managing quality & safety
Beverage companies have taken a proactive approach to managing water quality for many years. They understand and appreciate that water used to produce their product at the restaurant site can range significantly in quality and safety. Much is out of their direct control, as they rely on the food service establishment to ensure and sustain the quality of this water. To ensure greater consistency in water quality and safety, several leading beverage companies have developed water quality strategies that are carried out in the food service establishments. The primary strategy is water treatment at the point of ice and/or beverage production including specific product certifications for the treatment device(s). Similarly, and for the same reasons, individual franchises have developed water treatment strategies, i.e., Subway and others (see July Newsreel). By working together, beverage companies and food service establishments ensure customer satisfaction isn’t left to chance.
Ice production and water dispensing during peak times of operation can lead to the need for high flow rates with minimal pressure drop. Considering such establishments often operate for extended hours, seven days per week, there’s also a need for high treatment capacities to avoid frequent system maintenance. Common specifications for water treatment systems in the market today include the following:
Flow rate: 5 gpm
Maximum pressure drop at end of cartridge life: 10 to 20 psi
Where: gpm = gallons per minute
psi = pounds per square inch pressure
Common contaminants that can have a direct impact on the final beverage taste and odor include chlorine and chloramines. Chlorine remains the most common method of disinfection for public water supplies; however, it’s also one of the most common reasons consumers seek additional treatment of their water. While beverage companies add ingredients to flavor the water, few are effective at masking the unpleasant taste and odor of chlorine.
Similarly, chloramines can affect the taste and odor. Chloramines are finding increasing use across the United States--particularly in summer months--as an option to traditional chlorine for public water supply disinfection. The advantage is longer stability and less formation of unwanted treatment byproducts such as trihalomethanes (THMs). Chloramines, which are of keen interest to the beverage industry, are simply a combination of chlorine and ammonia. The resulting compound, however, is more difficult to treat using traditional chlorine reduction technologies, i.e., activated carbon.
As with any water supply, there’s a wide range of possible contaminants with health significance. The beverage industry has traditionally used a risk/benefit approach, taking into consideration the likelihood of the presence of certain contaminants and treatment needs and cost to manage them. The two contaminants that have risen from this analysis are protozoan cysts and turbidity.
Protozoan cysts are widespread and resistant to common forms of disinfection. Their infection is acute, and requires very low dose amounts. The illness is severe and can be life threatening. Protozoan cysts, including Cryptosporidium and Giardia, have a long history of waterborne outbreaks in spite of central treatment by public water supplies. Of 43 outbreaks identified by the Centers for Disease Control (CDC) from 1991-1998, 54 percent were directly attributable to protozoan cysts, making them the most common form of waterborne disease. CDC similarly tracks foodborne illnesses based upon laboratory-diagnosed cases. Last year, there were 541 reported cases of cryptosporidiosis. Surveillance of foodborne outbreaks for the past six years has shown an estimated increase of 8 percent in the incidence of crypto-sporidiosis.
Turbidity is formed from a large variety of organic and inorganic contaminants. These contaminants can impact taste, odor and general overall appearance of the finished product, in addition to having health effects. They’re more often associated with well waters, or with public water supplies that have poor or deteriorating distribution systems.
Technologies of choice
When considering the necessary flow rates and contaminants of concern, carbon block technologies have historically been the product of choice. Carbon is very effective at removing chlorine. It’s also very effective at removing chloramines, turbidity and cysts. These additional contaminants, however, require certain design changes to meet these additional performance claims.
Chloramine may require longer contact times between the carbon and water than chlorine. Additionally, carbon may need to have undergone specific activation processes for adequate chloramine reduction.
Turbidity and protozoan cysts fall into the category of particulate matter that can be removed through mechanical filtration. Carbon can be manufactured into blocks that have the required pore structure to accomplish direct mechanical interception of cyst particles. While there are other factors that may also contribute to reduction capabilities--such as the electric charge of the carbon block ingredients as well as the contaminant’s shape and electric charge--particulate matter is generally removed by the carbon block through direct interception. The treated water is allowed to pass through while the particulate matter remains. Over time, the filter will begin to accumulate sufficient material so as to restrict flow. This will signal a need for maintenance of the filter, i.e., cartridge replacement.
Testing & certification
The food service industry commonly requires treatment systems to be certified to the ANSI/NSF Drinking Water Treatment Unit (DWTU) standards for their specified performance claims. There are a total of six DWTU standards that cover a wide range of product technologies and performance claims. All of them include requirements for material safety, structural integrity and product literature. Table 1 details the applicable standard(s) for those contaminants discussed above along with the influent and effluent test requirements.
The food service industry benefits by taking a proactive approach to water quality. Patrons expect their food and beverage to meet minimum standards of quality and safety. Beverage quality can have a significant and immediate impact on patron satisfaction and future business. Water treatment for aesthetic contaminants can quickly reduce and possibly eliminate this concern. Considering the frequency and market impact of food and waterborne illnesses, water treatment in the food service establishment for health contaminants creates an important barrier to unwanted illness and risk to erosion of consumer confidence.
There are many products in the market today that can deliver the performance required to meet the needs of the food service industry. Existing product standards and third-party certification makes such steps of added protection simple and easy to implement.
About the author
Tom Bruursema is general manager of NSF International’s drinking water treatment unit testing and certification program. He is a 17-year veteran of NSF and holds a bachelor’s degree in science and a master’s degree in general biology from Eastern Michigan University. He can be reached at (734) 769-5575, (734) 827-7122 (fax) or email: bruursema@ nsf.org