Water Safety in Food Processing
Most people take water for granted. Everyone needs to do is turn on the tap at any time in the day or night to get clean, potable water. Water is used for drinking, cooking, washing and myriad other tasks.
So, the bottom line is that water is essential for life, health and even doing business, but it can’t be taken for granted. Food processors need large quantities of good quality water for a range of operations, including blending or mixing, cleaning, ice making, steam production and product transport. It is absolutely essential that food processors take steps to assure that the water and water systems in their plants are safe, wholesome and under their control.
Water as a Prerequisite for HACCP
The Hazard Analysis and Critical Control Point (HACCP) regulations for both the juice and seafood industries include eight areas where processors must have documented programs to assure good sanitation. One of these emphasizes the safety of water and ice used in food processing.
Sanitation controls. Each processor shall have and implement a sanitation standard operating procedure (SSOP) that addresses sanitation conditions and practices before, during, and after processing. The SSOP shall address: (1) Safety of the water that comes into contact with food or food contact surfaces or that is used in the manufacture of ice….
The Good Manufacturing Practices found in 21 CFR Part 110 also contains similar wording. The question is, “What can be done to assure that water quality is good?” The regulations state that “the water supply shall be sufficient for the operations intended and shall be derived from an adequate source. Any water that contacts food or food-contact surfaces shall be safe and of adequate sanitary quality. Running water at a suitable temperature, and under pressure as needed, shall be provided in all areas where required for the processing of food, for the cleaning of equipment, utensils, and food packaging materials or for employee sanitary facilities.
Most processors draw water from city water supplies or wells. The assumption is that these are safe sources but this needs to be verified.
There are also many operations that have additional treatment systems. They may be passing water through a reverse osmosis (RO) system to ensure that the water is cleaner or of better chemical quality when used as an ingredient. Other might chlorinate or ozonate their process waters, and there are those who pass water through ultraviolet (UV) light systems.
Each of these kind of systems need to be included on the company’s preventive maintenance program. Records that filters or ultraviolet sources are changed regularly will ensure that the system will function as designed, that is, it will keep water quality high and/or reduce the microbial load in that water.
The water must also be delivered to different areas within the plant at with sufficient pressure to do the job that needs to be done. For example, if a line contains a washer or washing step, the water pressure must be high enough to properly wash the product or unit operation. Operations that have problems with poor water pressure may be forced to install hold tanks with pumps to assure both adequate supply and pressure.
Most food processors use hot water for cleaning and other operations. Processors need to assure that they establish systems that allow them to heat sufficient quantities of water for all their needs. Ideally, these systems should allow them to control temperature to within the necessary parameters. This is something that most new plants would have, but is not as common in older facilities. Understanding water and wastewater flow is absolutely essential.
Processors should also examine all water lines and water handling systems to be sure that there is no potential for contamination within the operation.
Do you have back-flow prevention devices on water lines? Are there air gaps between spigots or hoses and water sources? Are hoses handled properly so that their use in the process will not contaminate product, equipment or ingredients? Operators need to teach plant staff how to handle and store hoses. Line workers often drag hoses across the floor, over equipment and use them to fill blending or mix tanks.
As noted, processors should conduct an audit of their water and plumbing systems. Such an audit will also help processors determine whether there are any “dead spots” or deadends in the lines.
Water lines remain clean because they are constantly flushed. Unused lines off a main or a large reservoir below the floor will not be flushed properly.
How ice is manufactured, stored and used is another issue that should be part of a processor’s water management program. There is a sense that plant workers and their managers believe that frozen water cannot be a source of contamination.
In many operations, especially in the seafood industry, water for chilling foods or blending is produced in large icemakers that deposit the ice in bins. Workers often “wade into” ice bins with shovels to fill bins with ice for production use. This is not a good practice since that ice may be used to chill foods.
The icemakers themselves also need to be cleaned and sanitized on a regular schedule..
Water Quality Analysis
All food processors should test water in the plant from different outlets at least once each year—and preferably more often. Operators should collect water samples from the farthest faucet from the line in the facility and preferably from the cold side. This should be done even if water is obtained from a city water system. The water quality as it leaves a treatment plant and its condition when it gets to your plant may vary.
This is especially true in cities where pipelines are old. If the water pipes are iron, it is quite easy to pick up that metal from the lines. High iron water, whether from old pipes or a natural source, is quite easy to detect. All one needs do is look for iron stains wherever there are leaks or drips.
Along these lines, processors should always request that the city provide them with water test results. These results are those obtained at the water treatment facilities. Having city water records does not preclude the processor from testing water from their own operations, however.
If water from multiple sources is being used (wells, city or wherever), be sure that samples from each source are tested. Both microbiological and chemical parameters should be tested.
Testing the microbiological quality of the water should be done more frequently. Be sure to establish documented programs for water sampling. These should include how to sample, how often to sample and where to sample. These procedures should also include what tests should be done and the methods for doing the work. If third parties are to be used for sampling and/or testing, be sure that the follow your procedures. Maintain all your records and testing procedures in a separate file or binder so that test results may be quickly and easily accessed.
Installing sample ports on water lines is a good idea, provided they are installed properly. Don’t leave a large deadleg. It is also a good idea to allow the sample port to “run” for a short period to flush the port. If water samples are being collected for microbiological testing and the water is chlorinated, be sure that the sampling program includes a step to neutralize any residual chlorine. (Nasco provides Whirl-Pak bags that include a thiosulfate tablet that will meet this need.) These bags are also safe to use in any kind of processing environment.
There are processors who have built additional safety into their systems by treating all waters entering the plant with chemicals or by UV light systems. Whether the added costs are worthwhile, only time will tell, but no effort to assure safety should be criticized.
Effects on Process Operations
Understanding water chemistry can benefit the processor in many ways. For example, baked goods do not contain large amounts of water but the chemistry of the water can affect doughs or batters, and eventually the finished baked good. Water acts as a solvent for salt, leavening chemicals, sugars, emulsifiers and all polar molecules.
Water may also contain dissolved minerals, organic matter, gases, and microbial contaminants. All of these factors are important to the bakery for overall quality assurance and sanitation. The amount and type of mineral salts present in water is very important to the baker. The degree of hardness is generally expressed as hard, soft, saline or alkaline. The specific composition is expressed in parts per million (ppm) of the dissolved hardness-causing minerals, mainly calcium and magnesium salts.
Cleaning and Sanitizing Water is almost a universal solvent. Flushing with water is the all-important first step in removing visible soil. According to Dennis Bogart of Randolph Associates, flushing is the most important step in cleaning. Bogart emphasized this point again and again at a recent symposium sponsored by the Institute of Food Technologists.[9] Cleaning compounds are used with water to enhance the cleaning ability of the water. Water carries detergents to the soil to be removed, it carries detergents and soils away from the surface and it can be used to sanitize a surface; assuming it is hot enough or contains antimicrobial compounds or sanitizers. Before selecting a cleaning compound, processors need to understand basic water chemistry and microbiology. Water used for cleaning should be of good microbiological quality. Table 2 shows recommended microbiological guidelines for water destined for cleaning.
The chemistry of the water, particularly water hardness, profoundly affects the performance of cleaning chemicals. Water hardness affects detergent consumption and may cause the formation of films, scale or precipitates on equipment surfaces. Failure to properly understand water chemistry can cost an operator money in both how much detergent is used and the time required for cleaning. Hardness is easy to measure, however, and is measured in grains or ppm. Table 3 defines water hardness.
When working with a supplier of cleaning compounds, be sure to be honest with them when they are developing your cleaning program. It is especially important to let them know if water is being drawn from multiple sources. The water chemistry from waters from different sources may differ significantly.
Water chemistry can also affect sanitizer performance. Chlorine is more effective at lower pHs. The lower the pH of the system, the more hypochlorous ion in the system, and hence, the greater the antimicrobial activity. If the pH of your water is 8.5, the efficacy of chlorination will be significantly reduced. If the water used is very hard, the processor may need to treat it. Water softening may be necessary for both processing and cleaning applications.
Plant Water Systems
Care must be taken when designing a factory to assure that there is not only enough water to meet the needs of processing, cleaning and employees, but that wastewater can be removed from the factory. This is something that needs to be done up front. If a plant adds production capacity without taking a close look at their water systems, significant problems can occur. The author has observed a factory whose toilets backed up and overflowed into the plant during peak production times. It is a good practice to label all water and sewage lines. The use of colored tape, arrows or paint will provide plant personnel and visitors with a quick reference to what is flowing within the pipes and the direction of flow.