Category Archives: Water Safety

USA – New Oyster Rules Aim to Reduce Vibrio Cases

Coastal Review

Division of Marine Fisheries Director Steve Murphey implemented the new oyster harvest control measures through Proclamation SS-1-2020  and Proclamation SS-2-2020, both issued Monday.

The Division of Marine Fisheries announced that while the state’s public health record concerning shellfish-related illnesses is one of the best in the country, the number of Vibrio cases nationwide had increased in recent years. Vibrio are naturally occurring bacteria in coastal waters that can cause illness in humans if precautions are not taken during the warmer months of the year.

The new regulations also will bring the state into conformity with guidance from the National Shellfish Sanitation Program, which is the federal, state and industry cooperative program recognized by the U. S. Food and Drug Administration and the Interstate Shellfish Sanitation Conference for the sanitary control of shellfish produced and sold for human consumption.

The changes include the following new requirements to:

  • Shade oysters harvested between May 1 and Oct. 14. This involves providing shade over harvested oysters or covering the oysters with a light-colored tarp or other nontoxic material while they are stored on the vessel, floating container when the oysters are not submerged, or a vehicle (this is already required for the harvest of clams in the summer).
  • Resubmerge oysters exposed to the air for greater than five hours between May 1 and Oct. 14 (this might occur during air-drying or de-fouling with gear such as OysterGro). The oysters must remain submerged for at least 14-days to abate Vibrio levels that may have been elevated.
  • Clarify that when working in intertidal waters the term “start of harvest” begins when the oyster is first exposed by the receding tide.
  • Clarify the tagging procedures when oysters leave the lease for tumbling or culling.
  • Resubmerge oysters moved from one growing area to another for at least 21 days prior to harvest (Certified shellfish dealers with a wet storage permit are exempt). This may prevent the closure of multiple growing areas in the event of an illness outbreak.

Previously implemented regulations pertaining to recording the start of harvest on the harvest tag and delivering the oysters to a licensed dealer within a specified time remain in effect.

For more information, contact Shannon Jenkins, chief of the division’s Shellfish Sanitatio

Research -Microbiological reduction strategies of irrigation water for fresh produce


Irrigation water can be a source of pathogenic contamination of fresh produce. The quality of the water used during primary production is important to control to ensure food safety and protect human health. Several measures to control the microbiological quality of irrigation water are available for growers, including preventative and mitigation strategies. However, clear guidance for growers on which strategies could be used to reduce microbiological contamination is needed. This study evaluates pathogenic microorganisms of concern in fresh produce and water, the microbiological criteria of water intended for agricultural purposes, as well as preventative and mitigative microbial reduction strategies. This article provides suggestions for control measures that growers can take during primary production to reduce foodborne pathogenic contamination coming from irrigation water. Results show that controlling the water source, regime, and timing of irrigation may help to reduce the potential exposure of fresh produce to contamination. Moreover, mitigation strategies like electrolysis, ozone, UV, and photocatalysts hold promise either as a single treatment, with pretreatments that remove suspended material, or as combined treatments with another chemical or physical treatment(s). Based on the literature data, a decision tree was developed for growers, which describes preventative and mitigation strategies for irrigation water disinfection based on the fecal coliform load of the irrigation water and water turbidity. It helps guide growers when trying to evaluate possible control measures given the quality of the irrigation water available. Overall, the strategies available to control irrigation water used for fresh produce should be evaluated on a case-by-case basis as one strategy or technology does not apply to all scenarios.

Research – As warming waters make shellfish toxic, a way of life becomes deadly for Native Alaskans.

Grist org

This summer, independent shellfish testing sites all over the state reported spikes in toxin levels, possibly related to the historic high temperatures in the water surrounding Alaska. And those warming waters are creating the ideal conditions for the algae that produce the toxin to propagate year-round, some researchers say.

Information – Controlling Legionella on Ships, Ferries & Maritime Vessels

Legionella Control

This expert guide from our water safety specialists looks at the control of legionella on ships, ferries and other maritime vessels. The guide considers the water safety risks that can arise on-board different vessels, the need to consider dry dock safety, why a detailed risk assessment and Water Safety Plan are essential, and concludes by outlining the potential consequences following an outbreak of Legionnaires’ disease.

When we hear about outbreaks of Legionnaires’ disease, we tend to associate them with scenarios that occur on land – in hotels, hospitals, leisure centres etc. However, there are similar opportunities for Legionella bacteria to grow and spread at sea too. Ships, ferries, cruise liners and other maritime vessels of all shapes and sizes can be affected, and as such must take suitable precautions to make sure their water systems are safe for those who use them or are exposed to them.

Research – How Temperature Influences Legionella Growth

Legionella Control

CDC legionella

Image CDC

In this review the experts at Legionella Control International look at how water temperatures influence legionella growth and how this information can be used to control the risks from the bacteria.

Under certain circumstances Legionella bacteria can lead to serious illness and fatalities in humans. Since Legionella bacteria can exist in man-made water systems, it is imperative to ensure the water is stored, maintained and distributed at temperatures that do not encourage the growth and spread of the bacteria.

There are three temperature ranges that have an influence on the growth and proliferation of Legionella bacteria. We’ll look at each of these in the link above.

Research – Prediction of Salmonella presence and absence in agricultural surface waters by artificial intelligence approaches

Wiley Online Salmonella kswfoodworld

The purpose of this study was to evaluate the performance of artificial intelligence tools for the prediction of Salmonella presence and absence in agricultural surface waters based on the population of microbiological indicators (total coliform, generic Escherichia coli, and enterococci) and physicochemical attributes of water (air and water temperature, conductivity, ORP, pH, and turbidity). Previously collected data set from six agricultural ponds monitored for two growing seasons were used for analysis. Classification algorithms including artificial neural networks (ANNs), the nearest neighborhood algorithm (kNN), and support vector machines (SVM) were trained and tested with a 539‐point data set for optimum prediction accuracy. Classification accuracy performances were validated with data set (400 samples) collected from different agricultural surface water sources. All tested algorithms yielded the highest accuracy around 75 ± 1% for generic Ecoli followed by enterococci (65 ± 5%) and total coliform (60 ± 10%). Classifiers calculated 6–15% higher accuracy ranging from 62 to 66% for turbidity than all other tested physicochemical attributes. Based on Ecoli populations measured in other water sources, trained algorithms predicted the presence and absence of Salmonella with an accuracy between 58.15 and 59.23%. The classification performance of ANN, kNN, and SVM algorithms are encouraging for the prediction of Salmonella in agricultural surface waters.

Research – Can Hard Water & Limescale Increase Legionella Risks?

Legionella Control

CDC legionella

Image CDC

This specialist guide has been written by the water safety experts at Legionella Control International and asks if the presence of hard water and limescale increases the risks from Legionella bacteria and Legionnaires’ disease. The guide looks at the formation of scale in water systems, fittings and appliances and how it can encourage the growth of biofilm and bacteria including legionella. It concludes by reviewing what practical measures can be taken to prevent, or at least reduce the risks that limescale brings with it.