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CAUTION regarding feeding RAW fish to DOGS !

“Canids (dogs / coyotes ) are the only species susceptible to salmon poisoning.

Parasites can be DEADLY in RAW Salmon - see excerpts below:

 “… The process of heating raw fish sufficiently to kill bacterial pathogens is also sufficient to kill parasites.

 

Freezing (-20ºC [-4ºF] or below [internal or external] for 7 days or –35ºC [-31ºF] or below [internal] for 15 hours) of fish intended for raw consumption also kills parasites. The Food Code recommends these freezing conditions to retailers who provide fish intended for raw consumption.

 

Brining and pickling may reduce the parasite hazard in a fish, but they do not eliminate it, nor do they minimize it to an acceptable level. Nematode larvae have been shown to survive 28 d in 80º salinometer brine (21% salt by weight).

 

Trimming away the belly flaps of fish or candling and physically removing parasites are effective methods

for reducing the numbers of parasites. However, they do not completely eliminate the hazard, nor do they minimize it to an acceptable level (FDA, 1998).”

 

FDA guidelines for freezing fish to kill parasites.

  • Freeze and store at -4°F (-20°C) or below for 7 days (total time); or

  • Freeze at -31°F (-35°C) or below until solid and store at -31°F (-35°C) or below for 15 hours; or

  • Freeze at -31°F (-35°C) or below until solid and store at -4°F (-20°C) or below for 24 hours.

Note: these conditions may not be suitable for freezing particularly large fish (e.g. thicker than six inches) (FDA, 2001)….”


"Fishing can be wonderful recreation, but sharing the catch with your dog
can be an act of kindness that kills.  Salmon Poisoning Disease is a
potentially fatal condition seen in dogs
that eat certain types of raw fish.
Salmon
(salmonid fish) and other anadromous fish (fish that swim upstream to
breed) can be infected with a parasite called Nanophyetus salmincola.
 

Overall, the parasite is relatively harmless. The danger occurs when the
parasite itself is infected with a rickettsial organism called Neorickettsia
helminthoeca. It’s this microorganism that causes salmon poisoning.


“Salmon poisoning occurs most commonly west of the Cascade mountain range,”
says Dr. Bill Foreyt, a veterinary parasitologist at Washington State
University’s College of Veterinary Medicine. He adds, “Canids (dogs) are the
only species susceptible to salmon poisoning
.
That’s why cats, raccoons and
bears eat raw fish regularly with out consequence.” Generally clinical
signs appear within six days of a dog eating an infected fish.... 

Common symptoms of salmon poisoning include:

  • vomiting
  • lack of appetite
  • fever
  • diarrhea
  • weakness
  • swollen lymph nodes 
  • dehydration

 

If untreated, death usually occurs within fourteen days of eating the infected fish.

Ninety percent of dogs showing symptoms die if they are not treated.  …

Thankfully, salmon poisoning is treatable if it’s caught in time. A key to its diagnosis is

telling your veterinarian that your dog ate raw fish. If you have a dog that wanders, or raids trash cans and you are unsure of what it’s eaten; consider the possibility of salmon poisoning.  Salmon poisoning can be diagnosed with a fecal sample or a needle sample of a swollen lymph node. Detecting the parasite’s eggs as they are shed in the feces confirms its presence. The rickettsial organism can be detected in a needle sample from a swollen lymph node. The combination of symptoms, and the presence of parasite eggs or the rickettsial organisms, are enough to justify treatment. …“

"Don't feed raw fish to your dog. Cook fish thoroughly or deep-freeze it for
a minimum of 2 weeks to destroy the parasite before feeding it to your dog."

"...If you chose to feed salmonids [Salmon (fish)] to a dog, the fish must be cooked or pressure canned

.. Salmon Poisoning Disease (SPD) is a misnomer. It  does not result from from ingestion of a toxin, rather it results from infection by a rickettsial organism,Neorickettsia helminthoeca. SPD has been known since the early 19th century in North America. It had been observed that dogs that ate raw salmon frequently died however the connection between the fluke and the rickettsia was not established at this time.(1) [(1) Smith, J.M., Dr. "Nanophyetus salmincola", World of Parasites,
 It is unusual in that the rickettsial organism does not directly infect the dog but is instead carried by a parasite, a trematode (flatworm or fluke) called Nanophyteus salmincola through two intermediate hosts first: freshwater snails and salmonid fish (salmon, trout, steelhead)….”

"... dogs and coyotes are considered incidental hosts and haven't evolved ways to counter invasion by the rickettsia

I would not feed any part of a raw salmon to a dog. That is the way to avoid the disease. Offal is more likely to be infected than meat, but any part of the fish could harbor these critters. ... The disease can result in a very sick dog - high fevers are common, gastrointestinal signs often occur, lymph nodes enlarge, dogs dehydrate and basically do all they can to die.   Sometimes salmon poisoning is difficult to distinguish from parvo.  .. "

"Raw salmon (mainly Pacific and fresh water) can contain rickettsial
parasites. Rickettsia is easily treated with antibiotics, but if untreated is fatal in 7-10 days."
"Nanophyetus salmincola or N. schikhobalowi are the names, respectively, of the North American and Russian troglotrematoid trematodes (or flukes).  Nanophyetiasis is the name of the human disease caused by these flukes. At least one newspaper referred to the disease as "fish flu." N. salmincola is responsible for the transmission of Neorickettsia helminthoeca, which causes
an illness in dogs that may be serious or even fatal."


The process of heating raw fish sufficiently to kill bacterial pathogens is also sufficient to kill parasites.

Freezing ( -20º C  [ - 4º F ] or below [internal or external]  for 7 days or –35º C [ - 31º F ] or below [internal]  for 15 hours ) of fish intended for raw consumption also kills parasites. The Food Code recommends these freezing conditions to retailers who provide fish intended for raw consumption.

Brining and pickling may reduce the parasite hazard in a fish, but they do not eliminate it, nor do they minimize it to an acceptable level. Nematode larvae have been shown to survive 28 d in 80º salinometer brine (21% salt by weight).

Trimming away the belly flaps of fish or candling and physically removing parasites are effective methods for reducing the numbers of parasites.  However, they do not completely eliminate the hazard, nor do they minimize it to an acceptable level (FDA, 1998).  FDA guidelines for freezing fish to kill parasites:

* Freeze and store at  [minus] - 4° F (-20°C) or below for 7 days (total time); or
* Freeze at [minus] - 31°F (-35°C) or below until solid and store at  - 31° F
(-35°C) or below for 15 hours; or
* Freeze at [minus]  - 31° F (-35°C) or below until solid and store at  [minus] -4° F

 (-20°C) or below for 24 hours.

Note: these conditions may not be suitable for freezing particularly large fish (e.g. thicker than six inches) (FDA, 2001)."

"Freezing raw fish prior to smoking remains the most effective way to ensure that viable parasites are not present in
cold-smoked products consumed by the public. It is essential, therefore, that raw fish potentially containing viable parasites be frozen and held in that state for a period of time that assures destruction of all viable parasites in that fish species.

4.2. Freezing
“Unlike bacteria, molds, and viruses, most parasites are relatively easy to destroy by holding the raw material or finished product at freezing temperatures for a specified period of time; of course, this is dependent upon the internal temperature of the material. The Fish and Fishery Products Hazards and Controls Guide recommends a temperature below  [minus] -4° F (-20 °C) for 7 days or -31° F (-35°C) (internal) for 15 hours to kill the parasites of concern (FDA 1998).   Although, based on the data currently available, these recommendations may appear stringent, it is because they were developed for the parasites that are considered most resistant to freezing (G. Hoskin 2001; personal communication; unreferenced). Already in 1975 (Food Chemical News, October 1975) Dr. G. J. Jackson cautioned that the anisakid nematodes vary in their ability to survive at low temperatures. For instance, certain species of anisakids have been reported to survive up to 52 hours at -4° F.

 

A number of other time and temperature regimes have been prescribed to accomplish the inactivation of parasites.  Another such option prescribes holding the fish at -10° F (-23° C) for 60 hours (Ching 1984). Alternatively, E.U. regulations require freezing at a temperature of no more than -4° F (-20° C) in all parts of the product for not less than 24 hours in order to control parasites in fish.

Some published studies support the effectiveness in controlling parasites by freezing at -4° F (-20° C) in all parts of the product for not less than 24 hours. Very early studies by Gustafson (1953) demonstrated that temperatures of less than -17° C (1.4° F) for 24 h could kill Anisakis larvae. Higher temperatures or

shorter times were not as effective. Studies in herring (Houwing 1969) demonstrated that at -4° F,

nematodes were killed in 24 hours, but if the product temperature reached -30° C (-22° F) by a

cryogenic method, the inactivation was immediate, and no further storage was necessary. A more

recent study by Deardoff and Throm (1988) used blast freezing to freeze salmon and rockfish

at -31° F (-35° C). Fish were stored frozen for 15 hours and then at -18° C (0° F) for up to 48 hours.

Out of 3,545, they found no viable larvae after 1 hour of storage at -18° C. Similar results were found

in herring by Karl and Leinemann (1989). They investigated the effect of freezing and cold storage on

survival of Anisakix simplex in herring and herring fillets at -20° C (-4° F) for 24 hours and found no surviving parasites.


Although Hauck (1977) reported no viable Anisakis after freezing, the conditions were not detailed.

The use of freezing has also been investigated for the control of other parasites of human health concern.

Although the World Health Organization (1979) indicated that freezing fish at -10° C (14°F)

for 5 days would kill all trematodes of concern, later research data indicate that longer times may be needed. For instance, Fan (1998) reported that metacercariae of Clonorchis sinensis from fresh water fish (Pseudorasbora parva) remained viable after frozen storage at -12° C (10° F)
for 10-18 days and -20° C for 3-7 days. As mentioned previously, clonorchiasis is not common in

Western countries. The metacercariae of Heterophyes are also very resistant to freezing; since they

survived 30 hours of storage at -10 or -20° F (Hamed and Elias 1970).

While the parasites can be killed by freezing the finished product, it is generally considered more appropriate to freeze the raw material prior to processing. Nematodes in particular will attempt to depart the gut during processing and will then establish themselves in the muscle during salting or smoking (Hauck 1977).

 

The result may be the presence of nematodes on the surface of the finished product, often perpendicular

to the surface. Their presence becomes a quality issue resulting in an aesthetically unwholesome
(although safe) product. For this reason, it is a good practice to freeze susceptible raw material, even for hot-smoked fish.

Visual inspection of the product before brining or smoking is also advised. This measure, however, is effective only to ensure that visible parasites are not present rather than to ensure inactivation of viable organisms. Similarly, inspection of fish after slicing will also assist in producing a quality product but cannot be relied upon for assurance against the presence of live parasites in product from commercial operations.

Some recent research has shown that the current regulation and production practice for fishery products does not protect the consumers against allergic hazards due to the ingestion of killed parasites. Audicana and others (1997) have reported that freezing of fish may not protect against allergenic reactions to ingested Anisakis simplex antigens in humans. This issue was discussed in an opinion paper from the Scientific Committee on Veterinary Measures Relating to Public Health (EC 1998) that identified parasite antigens (what is left of the parasite in the fish after it is frozen to kill the parasite) as a possible human health hazard."

ã Copyright 1995-2008 Helen L. McKinnon All Rights Reserved

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