The Importance of Water Quality in Food Safety

Jun. 24

There is a close relationship between water quality and food safety, for food production often involves the use of water. In the food industry, water is a critical resource. Water isn’t solely used as an ingredient, it is utilized in various stages of food production and or preparation. In essence, food preparation and processing require water. This is such an obvious fact that people would often take water for granted. Moreover, water quality’s influence over food products and various operations in food industries is not well understood by a significant number of people. This deficiency in understanding is one factor that leads to mismanagement of water, equipment operation, maintenance issues, loss of revenue, deterioration of product quality, and most importantly food safety.

Cleaning and sanitization of food products require water. This process is an essential part of processing operations in food production which makes water a requirement for food processing operations. Water also plays a vital role in the preservation and storage of food. The water activity of food or the ratio between the vapour pressure of food and the vapour pressure of water under identical conditions can be used as an indicator of the moisture condition of a food item. This water activity can also aid in determining the shelf-life of food products ultimately aiding in food safety. It is important to note that water quality is vital when it comes to food production processes and that the source of water and its application in food production needs to be considered.

Water can get contaminated in various ways and at any stage from the water reservoir to actual use. Physical, chemical, or biological agents can be introduced to food during production making them unsafe. Threats to both human and animal health can come from water that has been contaminated with several pathological microorganisms. This is one major challenge with regard to food safety. Usually, pathogenic microorganisms are the cause of diseases that are transmitted through unsafe freshwater. When it comes to producing, making, or preparing food, it is inevitable that water would be used. For the food to be considered safe, the water used to produce, make, or prepare the food must be free from pathogenic microorganisms. On top of this, it must be free from physical and chemical agents. The water’s aesthetic quality should also be acceptable, meaning that it must be free from undesirable taste, odour, colour, and impurities. The quality of the water should also adhere to safe drinking water standards.

Sources of Water

As mentioned earlier, water that is to be used in producing, making, or preparing food should be potable. It doesn’t matter what the exact source of the water is, it could come from surface water such as streams, rivers, lakes, groundwater from wells, or even rainwater and desalinated seawater. As long as the water meets health standards they wouldn’t compromise food safety. Although, where the water comes from would influence how the water would be treated to make them meet health standards.

Water used for drinking or food production should be treated so that it would meet health standards. There are two primary ways that the food industry receives water. They could receive water through public water distribution systems which are more common. Alternatively, they could receive water through a private supply.

Water in Food Production

With regards to food production, water is used for primary production, cleaning and sanitation, processing operations, and as a food ingredient.

Water in Primary Production

Water used for primary production refers to water used for watering crops, irrigation, maintenance of equipment, maintenance of the general hygiene of livestock, and livestock drinking. In other words, the water that is used in the agricultural sector, the largest consumer of water.

Crop Irrigation

Water that is to be used for irrigation needs to meet certain safety standards. If the irrigation water harbours pathogens, these pathogens may stay on the surfaces of the crops and even enter the crops through their roots.

The survival of enteric pathogens on plants has been studied in several research studies. Enteric pathogens can survive on a plant’s surface depending on the nutrition from the plants, UV irradiation, toxic compounds from plants, and desiccation. Most of the studies focused on E. coli and Salmonella. In these studies, researchers sprayed or applied directly onto the plant foliage water that contains the aforementioned bacteria. E. coli and Salmonella can survive on the surfaces of parsley or in the field for 177 and 231 days respectively. A specific strain of E. coli the O157:H7 strain can cause enterohemorrhagic diarrhea, they can survive in lettuce plants for up to 30 days. The manner in which the lettuce is irrigated affects the magnitude of E. coil O157:H7 contamination. In the studies conducted, the researchers introduced E. coli O157:H7 contaminated water through sprinkler irrigation and drip irrigation. The researchers noted that contamination is greater through sprinkler irrigation compared to drip irrigation. Moreover, contamination was more persistent in the lettuce leaves that were spray irrigated. The E. coli O157:H7 bacteria remained on the lettuce even after they are washed. This could mean that the E. coli O157:H7 bacteria are able to colonize the insides of the lettuce plant and remain in the plant’s tissues.

Besides E. coli O157:H7, other enteric pathogens can enter the insides of a plant through their stomata or any opening resulting from damage to the plant tissue. Pathogens were detected in the plant tissues through microscopy. After disinfection of the plant’s surface, the bacterial population was quantified.

Salmonella enterica can enter plant leaves, this ability of theirs is associated with their motility and chemotaxis. Some mutants of Salmonella enterica have abnormal flagella and are not motile. Due to this, they exhibited deficiency in motility, attachment, and penetration within plants. Those that have defective chemotaxis exhibited the same inabilities. Photosynthesis may have a role to play with regards to how enteric bacteria enter a vegetable. There are some studies that demonstrated the need for the type III secretion systems of Shiga toxigenic E. coli for the colonization of the stomata of leaves.

When enteric pathogens would enter a plant from the roots, they are often detected in the leaves or fruit. Lettuce plants that were cultivated using a hydroponic system that is contaminated with E. coli O157:H7 or Salmonella typhimurium or in soils that are irrigated with water that contains these pathogens remained positive for these bacteria even after they are surface-sterilized. The ability of S. typhimurium to produce a biofilm matrix played a role in their ability to enter parsley plants they enhanced the mobility of the S. Typhimurium through the parsley plants. Irrigation water that contains S. typhimurium can penetrate the parsley’s roots and translocate to the leaves and stems.

Livestock Farming

Determining pathogen contamination in water can be done in various ways. However, it is not practical to identify every single pathogen present in the water. This is where biological indicators come in. They can be used as a reliable indicator of how likely a pathogen, a disease-causing microorganism, is present in the water. The most commonly used biological indicator is the fecal coliform test. Fecal coliforms are bacteria that reside in the intestines of mammals and fowl. They are not normally found elsewhere. Since that is the case, where ever fecal coliforms are detected, be it in soils, vegetation, insects, or fish, means that they have been contaminated with feces from mammals and or fowl. Fecal coliforms are usually harmless, but we test for them because they are good indicators of the potential presence of other more harmful pathogens.

Fecal bacteria can enter surface waters when feces that contain them would enter these waters as sediment in overland runoff. In the case of water that has been used for primary production. The water used for maintaining hygiene in farm animals would end up carrying animal feces which may harbour fecal bacteria. A significant portion of the fecal bacteria may die but some of them can end up in areas of the water body that has the right conditions to allow them to survive. For instance, they could survive long term in bottom sludge or in the soil of the banks. Their survival in whatever water body they might end up in depends on the water itself, the soil around and beneath the water body, the air temperature, the size of the body of water, its flow rate, sediment volume, availability of nutrients and organic material, amount of light, soil type, pH, and several other factors.

Environmental conditions may vary from season to season and this can have an effect on the number of bacteria. While it is highly likely that shelter for livestock would have the same output of fecal matter all year round. The fecal output of wild animals may vary depending on the season.

With water being highly involved in agricultural activities, or primary production, being vigilant with its quality ensures food safety. When irrigation water quality is good, no pathogens would enter crops through their roots. Better management of livestock wastes reduces the likelihood of fecal matter entering water bodies or source water. With regards to primary production, it is of utmost importance that the agricultural products aren’t contaminated with pathogens.

Water in Sanitization

It is very difficult to clean, sanitize, or maintain hygiene without water. It is considered a universal solvent. Without it, removing dirt, or other impurities that would make something dirty would be tough. With regards to food handling, water is used to remove dirt or any residual chemicals that may be present in the ingredients. Flushing with water is usually the first step to cleaning ingredients. This is the same for equipment, instruments, or containers that would be used in the food production, making or preparation process. Water is also used in handwashing, so that food handlers won’t make food unsafe with their contaminated hands.

Even water that is to be used for sanitation may contain a significant number of microorganisms. However, as long as these numbers remain within safety limits they are safe for use in the sanitation and cleaning phases in food preparation. If water quality isn’t acceptable for sanitation purposes, they may require treatment before they can be used.

Water in Processing Operations

Food processing operations involve the use of water. Transport of products, dissolving ingredients, treatment of products such as alteration and separation, maintenance of appropriate water content in the final product, cooling processes, and steam generation processes are processes that use up water during food processing. With this regard, water management strategies can be applied so that the water would be utilized efficiently. Aside from that, a certain quality needs to be maintained. Especially that water reuse is encouraged whenever possible.

Whether water for reuse makes contact with water or not is an important thing to consider with regard to water reuse. With that said, there are two main types of water reuse; strategies that reuse water that came in contact with the food and strategies that reuse water that did not have any contact with the food. Reuse of water that does not come into contact with water usually occurs in the cooling and steam generation processes. For the other type of water reuse, water that is used for washing, transport, cleaning of equipment, and in the final product itself can be reused for various purposes.

Conserving and reusing water is an important part of the food processing industry. First of all, conserving and reusing water can reduce costs. Aside from that, they can conserve water and provide security of water supplies. The use of recycled water is highly tolerated. However, laws in several countries that support the use of recycled water require that recycled water has to be of the same quality as drinking water.

There are instances where nonpotable water is used in certain food processing operations. For instance, fishery products and shellfish are often washed with seawater. Another example would be fire control and steam generation. In these instances, the nonpotable water should not be mixed with the potable water, the nonpotable water should be clearly identified as nonpotable, and they shouldn’t be connected or mixed with the drinking water supply or used directly in food production.

Water as an Ingredient or Component of Food

Some food items use water as the main ingredient. There are also food items where water is an important component. Fruit juices, jams, jellies, pickles, soups, and more are some examples of food items where water is important. Aside from that, water may be used as a medium through which food can be preserved, stored, and consumed by humans. Water should be perceived as an important part of food items. With that said, water quality should be considered towards the goal of food safety. Therefore, it is essential that the water that is going to be used as a food ingredient would be free from undesirable colour, odour, taste, and impurities that are harmful to consumers and result in low-quality products.

Most households use ordinary tap water for food preparation. In most developed countries, tap water meets the criteria of the safe drinking water standard. However, it may not meet the qualifications mentioned earlier. Tap water may require further treatment. For instance, activated carbon filters can be used to remove undesirable odour and taste. On top of this, the activated carbon particles are capable of adsorbing substances like yeast, chlorine, and other substances that can affect odour and taste due to their massive surface area. They are also capable of removing nonpolar impurities such as mineral oil and polyaromatic hydrocarbons. Due to these properties, activated carbon filters can remove impurities that might interfere in subsequent treatment steps, like ion exchange and reverse osmosis.

Workers sorting mussels on a food processing line

Water-Borne Food Contaminants

Producing safe and secure food involves water safety which can be tackled by anticipating the possible negative effects of unsafe water. Infectious agents, toxic chemicals, and radiological hazards can enter the water and make them unsafe. These hazards can also contaminate food when water containing them is used in the food production process. Thus, when it comes to food safety, sufficient knowledge of various health hazards that may come from unsafe water is important.

Physical Contaminants

Physical contaminants are those contaminants that affect the colour, temperature, turbidity, taste, and odour of the water. They are derived from water that was not filtered properly. Most of the time, physical contaminants can be monitored through turbidity measurements. Some examples of physical contaminants include microphysical particles and some chemical contaminants. Microphysical particles include small particles of glass and metal. They can cause serious injury to a consumer when they are ingested. Inorganic elements like heavy metals, complex chemicals like pesticides, and organic compounds can compromise water quality. They are referred to as chemical hazards. There are various ways for chemical contaminants to enter the water. It may occur through environmental contamination, from chemical spills, or through incorrect usage of products such as pesticides. Chemicals could also enter the water supply through cross-contamination with sewage and/or industrial waste.

Biological Contaminants

There are a lot of microorganisms that could cause illness when they are ingested through contaminated water. However, other biologicals do not cause water-borne diseases themselves but the products that they release such as toxins do. Bacteria, viruses, protozoa, and helminths are microorganisms that cause water-borne illnesses. There are concerns about the transmission of prions through water, but research regarding this matter showed that prions aren’t transmitted through water. Each microorganism has its own resistances and vulnerabilities. Most treatment strategies assume the presence of all water-borne pathogenic microorganisms and employ methods that take advantage of the vulnerabilities of water-borne pathogens to effectively eliminate them from the water. Most of these pathogens do not originate from the water but rather are introduced into the water by animal and/or human sewage.

There are a few pathogens that normally reside in water. For instance, the bacteria Legionella, the causative agent of a serious type of pneumonia called Legionnaires' disease, is normally an environmental bacteria. Individuals can acquire an infection with Legionella when the water that contains this bacteria is aerosolized and subsequently inhaled. Wherever aerosol is generated in the food production process, the personnel responsible for that process are at risk of acquiring Legionella. Thus, preventing Legionella infections should be considered especially in areas where there had been cases of Legionella in the past. Besides that, Legionella prevention should also be considered if the food production facility provides shower rooms and washrooms to their employees, and if the facility utilizes cooling towers which can spread the bacteria into the wider surrounding. One method of preventing Legionnaires’ disease would be to maintain water temperatures below 20°C and above 60°C because at these temperatures the bacteria couldn’t grow and multiply.

There needs to be close communication between the appropriate municipal, provincial, or territorial water authorities and food industries. This is important because the exchange of information between the two is essential in cases of disease outbreaks caused by contaminated water. Essentially, the food industry is responsible for producing safe food but they would need close cooperation with the authorities in order to carry out their responsibilities properly.

Contaminated water poses a serious threat to human life which is why the food industry must be made fully aware of the possible water contaminants and their potential risk to human health. Besides knowing the potential risk, the appropriate steps towards safety should be taken.

Health Hazards in Water and Food Contamination

Most water-borne diseases are spread by pathogenic microorganisms that are transmitted through the consumption of contaminated freshwater. Water-borne diseases can be transmitted when water is used like bathing, washing, and drinking water or eating food that is exposed to contaminated water. However, infection with water-borne diseases usually occurs when contaminated water is drunk or used in the preparation of food. Diarrheal diseases are the most common water-borne disease and affect a lot of children in developing countries. Approximately 1.8 million human deaths annually are caused by diarrheal diseases according to the World Health Organization. Furthermore, they also stated that 58% of the annual deaths were attributed to a lack of safe drinking water supply, sanitation, and hygiene.

Final Thoughts

The food industry must have access to water because this resource is crucial in the processes related to food safety. Unfortunately, water quality and its influence on food safety are not well understood. This deficiency or even lack of knowledge regarding the importance of water quality in food production leads to mismanagement of water, equipment operation and maintenance issues, loss of income, food product quality, and safety.

Thus it is important to inform people involved in food production and safety about the importance of water quality. Aside from that, people should be educated on how water quality issues in various stages of food production can compromise the safety of the final product.