The warmer coastal water temperature produced by summer weather creates ideal conditions for bacteria that can contaminate oysters, the Washington State Department of Health reminded the public over the Fourth of July weekend.
Vibrio vulnificus and Vibrio parahaemolyticus, two types of bacteria that grow in warm waters and can cause human illness, are known to be carried by oysters, especially in summer months.
There is further information at the link above.
Posted in Bacteria, Food Hygiene, Food Illness, Food Inspections, Food Micro Blog, Food Microbiology, Food Poisoning, Food Safety, Food Safety Alert, Food Testing, Hygiene, Microbiology, Pathogen, Research, Vibrio, Vibrio parahaemolyticus, Vibrio vulnificans, Water
Tagged climate, nature, science, washington state department, washington state department of health
In December, Darrell Dishon became one of the approximately 15 people each year who succumb to vibriosis after eating raw oysters. Vibriosis is an incredibly rare disease — but Centers for Disease Control and Prevention data show that it’s getting more common.
“While all the other pathogens have shown a nice decline, the vibrios are about twice what it was since 1998. In a little over a decade, incidence has doubled. They’re still relatively small numbers — but it’s a very striking increase,” leading vibrio researcher Glenn Morris of the University of Florida’s Emerging Pathogens Institute told The Huffington Post.
Vibrio thrive in warm water. (That’s why the majority of cases happen in the summer, and why vibriosis is more closely associated with oysters from the Gulf of Mexico than from, say, the Pacific Northwest.) One widely publicized study published in July 2012 indicated that a 1-degree increase in the temperature of a body of water triples its vibrio population. For that reason, many scientists believe that climate change has contributed to the recent rise in vibriosis, and that it could make vibrio bacteria much more prevalent in coming years.
“Vibrios are in many ways the poster children for global warming, because they are so temperature sensitive and the temperature breakpoint for them is right around the point that we’re seeing temperature increases,” Morris explained.
The disease has already cropped up in places it had never been seen before: Israel, the Baltic Sea, even Alaska. Yet vibrio vulnificus, the form of vibrio bacteria that’s considered the most dangerous and the one that killed Dishon, remains most closely associated with oysters from the Gulf of Mexico. With only about 30 total cases in the United States a year, it’s exceptionally rare. Your chances of finding a valuable pearl in one of the 2.5 billion oysters Americans eat a year are about 100 times greater than your chances of contracting vibrio vulnificus.
Yet when it strikes, it strikes hard. It kills about half the people who get it, a rate comparable, among foodborne illnesses, only to the dreaded listeria monocytogenes. And many of these deaths are unusually painful.
The Cape Cod Times is reporting that eight cases of Vibrio food poisoning were reported in Massachusetts this year from oysters. Last summer the state designed new regulations to keep consumers safe from this bacteria, but they failed. The eight cases were linked to oysters harvested from Wellfleet, Orleans, Edgartown, Duxbury, Kingston, Barnstable, and Dennis.
Vibrio populations double every 15 minutes, so keeping shellfish cool is critical to controlling bacterial growth.
Vibrio was not seen in Massachusetts oysters until 2011 because the state’s colder water temperatures discouraged the growth of the bacteria. In every month in 2012, the mean air temperatures were higher than average, including the third-warmest April and the warmest August on record. Sea surface temperatures this year were the highest ever in the Northest.
Unsafe drinking water continues to burden developing countries despite improvements in clean water delivery and sanitation, in response to Millennium Development Goal 7. Salmonella serotype Typhi and Vibrio cholerae bacteria can contaminate drinking water, causing waterborne typhoid fever and cholera, respectively. Household water treatment (HWT) systems are widely promoted to consumers in developing countries but it is difficult to establish their benefits to the population for specific disease reduction. This research uses a laboratory assessment of halogenated chlorine beads treating contaminated water to inform a quantitative microbial risk assessment (QMRA) of S. Typhi and V. cholerae disease in a developing country community of 1000 people. Laboratory challenges using seeded well water resulted in log(10) reductions of 5.44 (±0.98 standard error (SE)) and 6.07 (±0.09 SE) for Salmonella serotype Typhimurium and V. cholerae, respectively. In well water with 10% sewage and seeded bacteria, the log(10) reductions were 6.06 (±0.62 SE) and 7.78 (±0.11 SE) for S. Typhimurium and V. cholerae, respectively. When one infected individual was contributing to the water contamination through fecal material leaking into the water source, the risk of disease associated with drinking untreated water was high according to a Monte Carlo analysis: a median of 0.20 (interquartile range [IQR] 0.017-0.54) for typhoid fever and a median of 0.11 (IQR 0.039-0.20) for cholera. If water was treated, risk greatly decreased, to a median of 4.1×10(-7) (IQR 1.6×10(-8) to 1.1×10(-5)) for typhoid fever and a median of 3.5×10(-9) (IQR 8.0×10(-10) to 1.3×10(-8)) for cholera. Insights on risk management policies and strategies for public health workers were gained using a simple QMRA scenario informed by laboratory assessment of HWT.
The Centre for Health Protection (CHP) of the Department of Health is investigating two fatal cases of Vibrio vulnificus infection, with one of them causing necrotising fasciitis (flesh-eating disease).
The case of necrotising fasciitis caused by Vibrio vulnificus affected a 48-year-old man with underlying medical conditions who lived in Shenzhen
His clinical diagnosis was necrotising fasciitis and bilateral above-knee amputations were performed. His condition continued to deteriorate and he passed away yesterday (June 19).
The patient’s blood culture grew Vibrio vulnificus and his tissue and wound swabs also detected Vibrio vulnificus.
The case of Vibrio vulnificus infection involved a 61-year-old man with chronic illness who lived in Yuen Long. He developed fever since June 16 and loss of consciousness on June 17. He was admitted to Pok Oi Hospital on the same day. His condition deteriorated and he passed away on June 18.
His blood specimen taken during his admission yielded Vibrio vulnificus.
The CHP’s investigation revealed that the patient had consumed raw mantis shrimp
Posted in Bacteria, Eurofins Laboratories, Food Hygiene, Food Illness, Food Inspections, Food Poisoning, Food Safety, Food Testing, Foodborne Illness, Microbiology, Pathogen, Vibrio, Vibrio vulnificans
Tagged blood specimen, flesh eating disease, health, loss of consciousness, mantis shrimp, medicine
Several recent outbreaks associated with oysters have heightened safety concerns of raw shellfish consumptions, with the majority being attributed to Vibrio spp. The objective of this study was to determine the effect of high-hydrostatic pressure (HHP) followed by mild heating on the inactivation of V. parahaemolyticus and V. vulnificus in live oysters. Inoculated oysters were randomly subjected to: a) pressurization at 200 to 300 MPa for 2 min at 21°C, b) mild heat treatment at 40, 45 or 50°C for up to 20 min and c) pressure treatment of 200 to 300 MPa for 2 min at 21°C followed by heat treatment at 40 to 50°C. Counts of V. parahaemolyticus and V. vulnificus were then determined using the most probable number (MPN) method. Pressurization at 200 to 300 MPa for 2 min resulted in various degrees of inactivation, from 1.2 to > 7 log MPN/g reductions. Heat treatment at 40 and 45°C for 20 min only reduced V. parahaemolyticus and V. vulnificus by 0.7 to 2.5 log MPN/g while at 50°C for 15 min achieved > 7 log MPN/g reduction. HHP and mild heat had synergistic effects. Combinations such as HHP at 250 MPa for 2 min followed by heat treatment at 45°C for 15 min and HHP at 200 MPa for 2 min followed by heat treatment at 50°C for 5 min reduced both V. parahaemolyticus and V. vulnificus to non-detectable levels by the MPN method (< 3 MPN/g). HHP at ≥ 275 MPa for 2 min followed by heat treatment at 45°C for 20 min and HHP at ≥ 200 MPa for 2 min followed by heat treatment at 50°C for 15 min completely eliminated both pathogens in oysters (negative enrichment results). This study demonstrated the efficiency of HHP followed by mild heat treatments on inactivation of V. parahaemolyticus and V. vulnificus and could help the industry to establish parameters for processing oysters.
FoodWorld 
