Safe Water: Who is Responsible?

Because U.S. water systems are regulated by the Environmental Protection Agency (EPA) for safe consumption, a processor could assume that the drinking water coming into the plant from a public water system is safe for food processing. Such an assumption, however, would be ill-founded. As with most food safety issues, it is not a lack of regulatory controls that cause most incidents, but accidental or deliberate contamination, lack of sufficient preventive controls, or simple human error.

Although important safeguards and increased regulation have gone into effect since the 90s, the 1993 “Milwaukee incident,” which linked more than 100 deaths and 400,000 illnesses to contaminated tap water, is still cited as a basis for processors’ relentless vigilance and internal testing of any incoming water supply used in the food-production process or on food-contact surfaces. The outbreak of cryptosporidium infection, which was confirmed by the Wisconsin Division of Health to have been caused by Cryptosporidium oocysts that passed through the filtration system of one of the city’s water-treatment plants, is said to have occurred while the Milwaukee Water Utility was in compliance with state and federal regulations of the time.

Even today, contaminated source water has been implicated as the cause of 79 percent of the outbreaks in ground water systems and, according to the Center for Disease Control and Prevention, contamination of drinking water in U.S. homes and businesses is usually a result of water main breaks or other emergency situations. While a new Ground Water Rule issued by EPA in late 2006 targets pathogenic-virus contamination of underground water sources and sets rules for increased vigilance against potential contamination by the disease-causing microorganisms, the possibility of contamination from the myriad of sources — and the effect of resulting product contamination — leaves little doubt that processors need to treat source water in the same manner as they do other incoming goods, and conduct regular safety testing.

Detection of pathogens in water is, however, different from other types of detection, says Dr. Syed Hashsham, associate professor in civil and environmental engineering at Michigan State University. “For water we have a very different system, a very different way to approach it.” One difference, he says, is that there are fewer preventive strategies; rather the focus in plants is more on detection and treatment.

“As a person who is responsible for quality,” Hashsham says of plant Quality Assurance managers, “I must make sure all the raw material is safe.” Thus, whether the plant utilizes a public or private water source, it is responsible for the safety of the water being used and should be able to test for some if not all waterborne pathogens. “I think there is a good amount of responsibility there.”

Whether the water is to be used in the product or for cleaning, says John Ricardi, vice president of Sensor Products Group for JMAR Technologies, Inc., developer of a laser-based microorganism detection and classification system, it has an effect on food safety, thus ensuring its quality is the responsibility of the quality assurance manager. “The QA manager is the person who has to be responsible to make sure that the product going out the door is safe.”

“There’s no treatment that’s 100 percent,” Ricardi says. Prevention through a filtration system or chemicals can be costly and because any system is subject to some extent of failure, they don’t always assure adequate removal of pathogens. Thus, he says, the ideal situation is to monitor or inspect the water just before it hits the end product or end use. 

Understanding the limits of individual plants, Hashsham notes that there is a balance to be struck between cost and safety by treatment facilities and in plants. “They’re always trying to find a balance between the two,” he says, adding that smaller communities often have lower requirements and that even the available tests have their limits. “The tests that are out there are based on a certain amount of risk that is acceptable,” he says. Whether that amount of risk is acceptable to the plant is an internal decision.

The actions and testing that a processor should take will vary depending on the water source. If a processor accesses a private supply from a well or surface source, the processor has full accountability for treatment and testing for quality and safety. If a public water system is used, the processor can expect that treatment and testing does take place, however, “You need to look at what [the water treatment plants] are testing and determine if that is enough for you,” Hashsham says. “Is it good enough? Do you need to test for the pathogens directly?”

Since 1999, water systems have had to provide an annual report to their customers on the quality of the drinking water. This Consumer Confidence Report must be distributed to customers, with many of the reports also available as a link from EPA’s website (http://www.epa.gov/safewater/dwinfo/index.html). Processors should review reports from their water supplier, Hashsham says, to ensure that the results of traditional assays (indicators) are within the limits that they deem necessary for their process; if results are not within plant specifications, then further treatment should take place at the plant level. It is important to note that by regulation most water utilities are only testing for indicators of pathogens (e.g., total and fecal coliforms and enterococci) and not for the pathogens themselves, he adds. “The indicator approach is cost effective but it is not foolproof. Pathogens are known to be present even when their indicators are absent. Hence a second barrier consisting of detection and treatment makes sense.”

REGULATORY ADVANCES. Although plants do need to take an active role in ensuring the water used in the plant is safe, water suppliers are being held to strict EPA standards, the most recent of which was a Ground Water Rule issued in late 2006, which targets pathogenic viral and bacterial contamination of underground water sources and sets rules for increased vigilance against potential contamination by the disease-causing microorganisms.

“More than 100 million Americans will enjoy greater protection of their drinking water” through the new rule, states a press release issued by EPA. The rule targets utilities that provide water from underground sources and requires greater vigilance for potential contamination by disease-causing microorganisms. The purpose of the “first-ever,” risk-targeting standards was to boost drinking water purity and public health security by helping communities prevent, detect and correct tainted ground water problems. The rule, requiring compliance by Dec. 1, 2009, provides for:

• regular sanitary surveys of public water systems to look for significant deficiencies in key operational areas.
• triggered source-water monitoring when a system that does not sufficiently disinfect drinking water identifies a positive sample during its regular monitoring to comply with existing rules.
• implementation of corrective actions by ground water systems with a significant deficiency or evidence of source water fecal contamination. 
• compliance monitoring for systems that are sufficiently treating drinking water to ensure effective removal of pathogens.

DETECTION. The key developments in waterborne pathogen detection technologies have been based on polymerase chain reaction (PCR) assays which detect certain signature gene fragments, Hashsham says. The advantages of the real-time PCR is that it provides for significant sensitivity and specificity; this method can assess a large number of pathogens in a single assay. A disadvantage is the lag time; the tester has to be able to amplify the DNA, so the sample has to be processed or a concentrated sample used. In addition, he says, “the person has to be somewhat knowledgeable in microbiology.”

Another method used to detect pathogens in water is the immunoassay antibody-based test. This method will enable quicker results, but it provides less sensitivity and specificity; its capability is limited to availability of antibodies. Detecting dozens of pathogens using an antibodies assay is more challenging than are DNA-based methods, Hashsham explains.

The two methods also work well together. Suitable for general use, the immunoassay method can “raise a flag” that a potential problem exists. Then the PCR testing can be used for in-depth analysis. In addition, Hashsham says that both methods are continuing to develop. “Those two are pushing the envelope in different directions.”

Hashsham himself has a research focus in the development of DNA biochips for parallel detection of microorganisms important to drinking water and wastewater, and received state funding for development of a low-cost, high-density DNA biochip for detecting all relevant pathogens for a given niche and EPA funding for a bioinformatics pilot program in waterborne disease microorganisms.

With Dr. James Tiedje, Michigan State University Distinguished Professor and Director of the Center for Microbial Ecology, and Dr. Erdogan Gulari, professor of chemical engineering at the University of Michigan, Hashsham has developed a chip that can test for more than 20 pathogens together but it is still a lab assay. The team is now working on a hand-held device to house the DNA biochip and make the PCR testing more available for on-site plant testing.

The question, Hashsham says, is whether the DNA biochip can be modified to do PCR and be put into a hand-held device. In addition to its portability, the device is expected to require minimal training, screen for a number of pathogens at the same time and be available for a reasonable cost, he says. A team of graduate students and technicians are currently working on the devices and field testing and services will be conducted through AquaBioChip LLC, formed by the team though a grant from the Michigan Economic Development Corp. The system, Hashsham says, “is something that is much better than most methods to screen for multiple pathogens in a single assay, and we are also working to improve it further.”

Inline detection also is continuing to evolve with new technology enabling real-time monitoring and detection for presence of harmful pathogens, Ricardi says. Although validation is still essential, the real-time alert means that plants can react immediately and proactively to divert the suspected water until verification is conducted, and treatments made if needed.

It is this very speed of detection and increased ability to detect multiple pathogens quickly and easily that are driving continued improvements in the science of detection of waterborne pathogens. And it is these advances, regulatory standards and compliance of suppliers, and continued vigilance in plants that will keep food safe from waterborne contamination.   QA

Lisa Lupo is staff editor of QA magazine. She can be reach at llupo@giemedia.com.

Drinking Water Pathogens and Indicators

As part of a national research project to support development of national drinking water standards which protect public health, EPA has collected Information Collection Rule (ICR) data. Included in the ICR is a reference resource listing the following as key drinking water pathogens and their indicators:

• Disinfection byproducts — formed when disinfectants used in a water treatment react with bromide or natural organic matter (i.e., decaying vegetation) present in the source water. Different disinfectants produce different types and/or amounts of disinfection byproducts. Regulations are currently being implemented or are scheduled to be implemented for trihalomethanes, haloacetic acids, bromate, and chlorite.
• Total coliforms — closely related, mostly harmless bacteria that live in soil, water and the gut of animals. The extent to which total coliforms are present in the source water can indicate the general quality of that water and the likelihood that the water is fecally contaminated. Total coliforms are currently controlled in drinking water regulations (i.e., Total Coliform Rule) because their presence above the standard indicates problems in treatment or in the distribution system. EPA requires all public water systems to monitor for total coliforms in distribution systems.
• Cryptosporidium — a single-celled, protozoa microbe which may cause cryptosporidiosis when ingested. Symptoms can range from mild stomach upset to life threatening disease. EPA regulates Cryptosporidium in drinking water by requiring filtered surface water systems serving at least 10,000 to physically remove at least 99% of Cryptosporidium. Systems without filtration must adopt a watershed control program to protect the source water from Cryptosporidium contamination.
• Giardia lamblia — single-celled, protoza microbes. When ingested, they can cause the gastrointestinal disease giardiasis, for which symptoms may include diarrhea, fatigue and cramps. Waterborne giardiasis may be caused by disinfection problems or inadequate filtration procedures. EPA regulates Giardia in drinking water by requiring water systems that use surface water or ground water under the direct influence of surface water to disinfect and/or filter water so at least 99.9% of Giardia are rendered harmless or physically removed.
• Viruses — microbes, including hepatitis A virus, rotaviruses, and Norwalk and other caliciviruses, that can cause illness. EPA regulates viruses in drinking water by requiring water systems that use surface water (or ground water under the direct influence of surface water) to treat their water to ensure that 99.99% of viruses are rendered harmless or physically removed.