"Sous Vide for the Home Cook" by Douglas Baldwin

[Tatoosh]

I will buy your book this month to be sure! But I am confused about cooking sous vide at 131F while I have the FDA saying anything below 140F is in the danger zone. Above that, I understand the effect of temperature and time. But under the 140F I'm faced with "supposedly" unsafe food. I am cooking ground beef burgers sous vide and finishing them in a deep fryer. Since it is ground beef, it is more "temperatmental" about bacteria than a steak, but how do I resolve the difference between 131F (medium rare) and 140F (medium) in terms of food safety, time at temperature and o forth?

[Shalmanese]

Bacteria stops reproducing at around 120, starts dying at around 125 and dies pretty much instantly at 140. Between 125 and 140, you had to hold food at that temp for a minimum amount of time to get enough die off. Before SV, it wasn't practical to do this so the FDA didn't really talk about it.

[DouglasBaldwin]

Thank you Shalmanese for your quick response to Tatoosh's question. To add a little detail, let me quote the food safety section of my web guide:

So why were you taught that food pathogens stop multiplying at 40°F (4.4°C) and grow all the way up to 140°F (60°C)? Because it takes days for food pathogens to grow to a dangerous level at 40°F (4.4°C) (FDA, 2011) and it takes many hours for food to be made safe at just above 126.1°F (52.3°C) – compared with only about 12 minutes (for meat) and 35 minutes (for poultry) to be made safe when the coldest part is 140°F (60°C) (FSIS, 2005; FDA, 2009, 3-401.11.B.2). Indeed, the food pathogens that can multiply down to 29.7°F (-1.3°C) – Yersinia enterocolitica and Listeria monocytogenes – can only multiply about once per day at 40°F (4.4°C) and so you can hold food below 40°F (4.4°C) for five to seven days (FDA, 2011). At 126.1°F (52.3°C), when the common food pathogen Clostridium perfringens stops multiplying, it takes a very long time to reduce the food pathogens we’re worried about – namely the Salmonella species, Listeria monocytogenes, and the pathogenic strains of Escherichia coli – to a safe level; in a 130°F (54.4°C) water bath (the lowest temperature I recommend for cooking sous vide) it’ll take you about 2½ hours to reduce E. coli to a safe level in a 1 inch (25 mm) thick hamburger patty and holding a hamburger patty at 130°F (54.4°C) for 2½ hours is inconceivable with traditional cooking methods – which is why the “danger zone” conceived for traditional cooking methods doesn’t start at 130°F (54.4°C). (Note that Johnson et al. (1983) reported that Bacillus cereus could multiply at 131°F/55°C, but no one else has demonstrated growth at this temperature and so Clostridium perfringens is used instead.)

[Tatoosh]

Thank you both. I apologize for missing the food safety explination on your website, but now I have a pretty good understanding of why the temperatures are specified and how to answer questions about the lower sous vide temperatures confidently.

[PedroG]

The "danger zone"

Be aware that

The concept of the "danger zone" is based on an oversimplification of microbial growth patterns. Not all temperatures within the danger zone are equally dangerous. Most pathogens grow slowly at temperatures below 10°C/50°F. Their growth accelerates modestly with increasing temperature and is typically fastest near human body temperature, 37°C/98.6°F. Beyond this optimum, higher temperatures sharply curtail the growth of most pathogens until they stop growing completely and start to die.

(see the wikiGullet article on the Danger Zone).

So holding ground beef at 10°C/50°F is not nearly as dangerous as holding it at e.g. 40°C/104°F.

On the other hand, holding fish at 4.0°C/39°F, i.e. below the "danger zone" won't keep it fresh. Fish living in arctic seawater have (autolytic and other) enzymes and may harbor microbes adapted to temperatures down to -1.9°C/28.6°F (freezing point of seawater), so they are more susceptible to spoilage even at refrigerator temperatures of 4.4°C/40°F; it is preferable to store fish on crushed ice and eat it before it eats itself.

[Tatoosh]

Okay, so let's run a hypothetical with store bought ground beef. I season, form patties and vacuum seal. Then I cook from refrigerated temp of 41F. The patties are 6 ounces, 4 to 4 1/2 inches wide and a bit over 1 inch thick, let us say about 30 millimeter thick. Cook time via sous vide using Mr. Baldwin's guide is about 1 1/4 to 1 1/2 hours. I cook at 140F to 150F depending on the consumer's preference. They are finished in a deep fryer at 400F. If I want to hold these for a period of time, say up to 2 or 3 hours, a 125F bath would do without undue concern, since the burgers are vacuum packed. In fact, I could cook them (given enough time) and serve as rare. But Mr. Baldwin starts at 131F and that I take that as a good place to start holding my burgers until time to finish and the lowest temperature I would cook them at so they would be medium-rare.

Since I am in the Philippines which often does not enforce the same standards of food safety and handling that are common in the USA (though they surely do teach them in their culinary courses here), I tend to preparing burgers medium to medium-well. But I still need to hold them for the above mentioned periods until time to finish. The 131F to 135F range seems to be a safe place to keep them for extended periods without food safety issues or degradition of the finished product?

Edited March 7, 2012 by Tatoosh (log)

[PedroG]

The "danger zone"

Be aware that

(see the wikiGullet article on the Danger Zone).

So holding ground beef at 10°C/50°F is not nearly as dangerous as holding it at e.g. 40°C/104°F.

On the other hand, holding fish at 4.0°C/39°F, i.e. below the "danger zone" won't keep it fresh. Fish living in arctic seawater have (autolytic and other) enzymes and may harbor microbes adapted to temperatures down to -1.9°C/28.6°F (freezing point of seawater), so they are more susceptible to spoilage even at refrigerator temperatures of 4.4°C/40°F; it is preferable to store fish on crushed ice and eat it before it eats itself.

If you are looking for the wikiGullet article on the Danger Zone, you will see a blank page (wikiGullet is no longer being maintained), but you can view it in the sous vide Wikia.