Modernistiskt kök, vol 1, p122 (innehåller min djärva ):
A separate family of parasitic worms, known as nematodes or anisakids,
includes species such as Anisakis simplex and Pseudoterranova
decipiens (which is also listed under the genus Terranova or
Phocanema). These worms follow a life cycle that resembles that of trichinae but in a marine environment.
Raw fish poses the biggest risk
of infection because cooking fish to an internal temperature of 60 °C
/ 140 °F or more for at least one minute kills the worms. Several food
safety guides assert that 15 seconds at an interior temperature of 63
°C / 145 °F will also do the trick. Those temperatures, however, are
high enough to overcook the fish, at least to many people’s taste.
Not
surprisingly, sushi-loving Japan is the epicenter of foodborne
anisakid infections, also known as anisakiasis. Tokyo alone tallies
about 1,000 cases annually, most of which are from home-prepared sushi
and sashimi. Only rarely are sushi bars with professional sushi chefs
implicated. The U.S. reports fewer than 10 cases a year.
Anisakid
infection occurs more frequently in certain fish species that
fishermen catch near the shore, such as salmon, mackerel, squid,
herring, anchovies, and rockfish, than it does in other species.
Coastal fish are more likely to eat infected copepods that regenerate
in seals and other marine mammals. Farmed salmon do not eat copepods
and are therefore generally anisakid-free, as are wild tuna and other
deep-ocean species.
Wild salmon, however, are especially prone to
infection. In 1994, for instance, an FDA study found anisakids in 10%
of raw salmon samples that were obtained from 32 sushi bars in the
Seattle area. Despite this alarming statistic, human anisakiasis cases
are still relatively rare because most ingested larvae die or pass
harmlessly through the intestinal tract.
The technique traditionally
used by chefs to detect worms requires them to hold fish fillets up to
a light and inspect them visually, a procedure called candling. Master
sushi chefs say they can feel the worms with their fingers. And
although some chefs can indeed find a few worms through candling or
handling, studies suggest that others may be easily missed, especially
in salmon or mackerel. No matter how experienced the sushi master,
then, neither method is fully reliable.
Freezing kills anisakids, and
in this way the food industry ensures that worms pose no health risk
in fish that is served raw. For commercial retailers, the FDA
recommends freezing and storing the fish in a blast freezer for seven
days at −20°C/−4°F, or for 15hours at −35°C/−31°F. Most sushi is, in
fact, frozen before it is served; the 1994 FDA study found that all
but one of the anisakid worms spotted in the Seattle sushi were dead
or dying—casualties of the freezing process. If done improperly,
however, freezing can negatively affect the taste and texture of the
fish.
Modernistiska köket, vol 1, s. 123-124 (moreso Asien, men för eftertiden är det värt att nämna):
[ … ] species of liver fluke are endemic to Asia and Eastern Europe,
where researchers have linked them to eating raw or undercooked
freshwater fish.
Researchers have tied many infections, mostly in Asia, to eating raw,
pickled, or poorly cooked freshwater crabs and crawfish (especially
Chinese “drunken crabs”) that are contaminated with lung flukes,
another major fluke group comprising eight known species. These
animals produce a serious human disease called paragonimiasis, in
which immature worms infect the lungs and encapsulate themselves in
protective cysts, where they can remain for decades.
En tabell om frysningstider av FDA:
Så,förattdödaparasiter,ärensprängfrysarevägenattgå.
Efteråtmåstevilagamatförattbliavmedotäckabakterier.
Dettaärminsousvidebibel: länk
Kokhåll sous vide (håll temperaturen och servera):
For cook-hold sous vide, the main pathogens of interest are the Salmonella species and the pathogenic strains of Escherichia coli. There are, of course, many other food pathogens but these two species are relatively heat resistant and require very few active bacteria (measured in colony forming units, CFU, per gram) to make you sick. Since you’re unlikely to know how contaminated your food is or how many of these bacteria your (or your guests) immune system can handle, most experts recommend a 6.5 to 7 decimal reductions of all Salmonella species and a 5 decimal reduction of pathogenic E. coli.
Cook-chill sous vide (chill efter tillagning för senare uppvärmning och servering):
For cook-chill sous vide, Listeria monocytogenes and the spore forming pathogenic bacteria are our pathogens of interest. That’s because Listeria is the most heat resistant non-spore forming pathogen and can grow at refrigerator temperatures (Nyati, 2000b; Rybka-Rodgers, 2001), but appears to require more bacteria to make you sick than Salmonella or E. coli. Most experts recommend a 6 decimal reduction in Listeria if you don’t know the contamination level of your food.
While keeping your food sealed in plastic pouches prevents recontamination after cooking, spores of Clostridium botulinum, C. perfringens, and B. cereus can all survive the mild heat treatment of pasteurization. Therefore, after rapid chilling, the food must either be frozen or held at
- below 36.5°F (2.5°C) for up to 90 days,
- below 38°F (3.3°C) for less than 31 days,
- below 41°F (5°C) for less than 10 days,
- or below 44.5°F (7°C) for less than 5 days
to prevent spores of non-proteolytic C. botulinum from outgrowing and producing deadly neurotoxin (Gould, 1999; Peck, 1997).
Vi konsumerar alla små mängder skadliga bakterier som går igenom vårt system okänt, så vi pratar om matlagning till säkra nivåer.
Det finns en enkel tabell med data för detta, och det är baserat på tjockleken på de föremål du lagar sous vide. Tänk på att de cylindriska föremålen kommer att lagas snabbare i sous vide än deras relativt lådformade motsvarigheter (en roulad, till exempel en 1 "tjock biff).
Också, beroende på köttet, vill du laga det till en annan temperatur för att skölja de specifika bakterierna (fisk vs kyckling mot nötkött)
Det finns flera tabeller med data:
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391.133
Table 3.1: Pasteurization times for a one million to one reduction of Listeria in fin-fish. I used D605.59 = 2.88 minutes for lean fish (such as cod) and D605.68 = 5.13 minutes for fatty fish (such as salmon) from Embarek and Huss (1993). For my calculations I used a thermal diffusivity of 0.995×10-7 m2/s, a surface heat transfer coefficient of 95 W/m2-K, and took β = 0.28 (to simulate the heating speed of a 2:3:5 box).
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391.133
Table 4.1: Time required for at least a one million to one reduction in Listeria and a ten million to one reduction in Salmonella in poultry starting at 41°F (5°C). I calculated the D- and z-values using linear regression from (O’Bryan et al., 2006): for Salmonella I used D606.45 = 4.68 minutes and for Listeria I used D605.66 = 5.94 minutes. For my calculations I used a thermal diffusivity of 1.08×10-7 m2/s, a surface heat transfer coefficient of 95 W/m2-K, and took β=0.28 (to simulate the heating speed of a 2:3:5 box). For more information on calculating log reductions, see Appendix A.
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391.133
Table 5.1: Time required to reduce Listeria by at least a million to one, Salmonella by at least three million to one, and E. coli by at least a hundred thousand to one in thawed meat starting at 41°F (5°C). I calculated the D- and z-values using linear regression from O’Bryan et al. (2006), Bolton et al. (2000), and Hansen and Knøchel (1996): for E. coli I use D554.87 = 19.35 min; for Salmonella I use D557.58 = 13.18 min; and for Listeria I use D559.22 = 12.66 min. For my calculations I used a thermal diffusivity of 1.11×10-7 m2/s, a surface heat transfer coefficient of 95 W/m2-K, and took β=0 up to 30 mm and β=0.28 above 30 mm (to simulate the heating speed of a 2:3:5 box). For more information on calculating log reductions, see Appendix A. [Note that if the beef is seasoned using a sauce or marinate which will acidify the beef, then the pasteurizing times may need to be doubled to accommodate the increased thermal tolerance of Listeria (Hansen and Knøchel, 1996).]
Det finns också ett bord för regeringen (jag antar USA: s regering) förgräsningstider:
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Förutom en lista över källor:
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