BlueTrace Blog

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Vibrio and Food Safety

By Chip Terry on Aug 24, 2021 1:43:50 PM

The success of our businesses rely on consumers staying healthy.

One bad oyster... one sick customer...one Instagram post and you can have thousands of people opting for wings instead of oysters next time they go to the bar.  

For shellfish, the most prevalent issue is Vibrio--a salt tolerant bacterium that is endemic to pretty much all waterways.  The most common variation is Vibrio Paralyticus.  The most deadly is Vibrio Vulnificus.  The Centers for Disease Control (CDC) estimates over 52,000 Americans get sick from Vibrio each year. By the CDC estimate, ~60% of VP infections are from oysters and ~15% are from clams.

Side note: the CDC number is an estimate, documented cases are much fewer and many would argue the real number is much lower.  But in any case one sickness is too many. 

Vibrio control involves keeping the concentration below the level that will get someone sick. The vast majority of time if you harvest product and cool/ice it quickly there will be no issue.  Although this summer in Washington State the water got warm enough in some areas that oysters straight out of the water and handled properly had elevated Vibrio levels that led to sicknesses and recalls.  The details are still being explored, but by all accounts the industry and regulators acted quickly and thoughtfully and prevented a bigger issue. 

NOAA has published an interesting set of data on the predicted level of Vibrio in various waterways.  Couple of key takeaways: 

1) At 90 degrees vibrio can double in a hour.  

2) On-board Icing or Rapid Refrigeration provides the best protection

3) Middle of the day in hot weather is a bad time to harvest

In response to the issue of Vibrio, the ISSC and most state agencies have adopted a series of rules to reduce the prevalence. Most of the rules involve cooling rapidly.  For instance: in Florida in the summer you must harvest early in the morning and have them in cooling within 30 minutes.  The ISSC has a list of all regulations

No one likes to follow regulations that can seem seem arbitrary, but the science is compelling.  Keep your product cool. 

 

 

 

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