Tag Archives: Sous Vide

Heston or Hugh? Sous-vide risk

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Scientists from Public Health England analysed 34 meals from restaurants, hotels and pubs which were mostly made up of chicken or duck breast cooked in a water bath.

They found the ‘sous-vide’ method of simmering vacuum-packed foods in a water bath could increase the risk of food poisoning.

The technique, pioneered by celebrity chefs like Heston Blumenthal, is lauded for its ability to preserve flavour and texture, but it braises food well below the 100C boiling point of water

Sales of sous-vide machines, which can cost up to £400, are reported to have increased by around 300 per cent in recent years in the UK 

The results, in the journal Epidemiology and Infection, showed ten had ‘unsatisfactory’ levels of bacterial contamination and another eight were borderline.

Microbiologist Professor Hugh Pennington, who investigated the deaths of 21 people in Scotland in 1996 from an outbreak of E.coli, said: ‘I would not want to eat anything that had not been heated through properly.’

I’ll go with Hugh.

Food Safety Talk 79: You’re Into Botulism Country (with Merlin Mann)

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Food Safety Talk, a bi-weekly podcast for food safety nerds, by food safety nerds. The podcast is hosted by Ben Chapman and barfblog contributor Don Schaffner, Extension Specialist in Food Science and Professor at Rutgers University. Every two weeks or so, Ben and Don get together virtually and talk for about an hour.  They talk about what’s on their minds or in the news regarding food safety, and popular culture. They strive to be relevant, funny and informative — sometimes they succeed. You can download the audio recordings right from the website, or subscribe using iTunes.3024499-poster-p-meat

Merlin Mann joins Don and Ben for a discussion on food safety and cooking using science at home.

The episode starts off with a discussion on sous vide and time/temperature combinations for pathogen reduction.

The discussion goes to Harold McGee’s On Food and Cooking and the science of cooking, sensory and how heat changes food quality and safety. The guys talk about ground meats risks compared to intact muscle meats and then deconstruct risk assessments with bullet analogies. The guys move into pork and trichinosis and how risks have changed but messages stay sticky.

The show ends with a discussion on food safety myths, including confusing food safety and spoilage; storing butter on the counter and  ketchup in the refrigerator.

They decided to leave an in-depth discussion of Sloan for another day.

Guidance on sous vide cooking for caterers in Ireland

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The Food Safety Authority of Ireland has develop guidelines for sous vide, which is French for ‘under vacuum’, is a method of cooking where food is vacuum-packed in a plastic pouch and heated in a temperature controlled bath for a defined length of time. This cooking method can present some food safety risks which should be identified and controlled. These include the potential for survival and growth of bacteria that can grow under the anaerobic (absence of oxygen) conditions created by the vacuum packaging, e.g. Clostridium botulinum.sous vide ireland Screen Shot 2015-08-06 at 9.17.57 PM

Due to the rise in the use of the sous vide cooking in restaurants and catering establishments, the FSAI has prepared a factsheet which highlights the risks associated with this method of cooking. It provides guidance on managing these risks, in particular guidance on cooking temperatures and times. It also makes recommendations for cooling, storing and reheating food that has been cooked by sous vide.

Click here for the guidelines.

Irish guidance on sous vide cooking for caterers

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The Food Safety Authority of Ireland says, sous vide, which is French for ‘under vacuum’, is a method of cooking where food is vacuum-packed in a plastic pouch and heated in a temperature controlled bath for a defined length of time.

Sous VideThis cooking method can present some food safety risks which should be identified and controlled. These include the potential for survival and growth of bacteria that can grow under the anaerobic (absence of oxygen) conditions created by the vacuum packaging, e.g. Clostridium botulinum.

Due to the rise in the use of the sous vide cooking in restaurants and catering establishments, the FSAI has prepared a factsheet which highlights the risks associated with this method of cooking. It provides guidance on managing these risks, in particular guidance on cooking temperatures and times. It also makes recommendations for cooling, storing and reheating food that has been cooked by sous vide.

The factsheet is available on our website at: www.fsai.ie/publications_sous_vide

Sucking air out of a baggie containing raw chicken is beyond dumb

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State-sponsored jazz, NPR, says it’s getting crafty in the kitchen this summer.

bird.bag.sous.videIt’s another triumph of food porn over food safety.

In a story about making magically moist sous vide chicken without the fancy equipment, chef Christina Tosi says consumers can cook chicken with a spiced-buttermilk sauce sous-vide, in just 5 to 20 minutes, with a Ziploc bag.

Judge the recipe for yourselves:

You’ll need a chicken breast or boneless thigh, seasoning of your choice (either salt and pepper or a spice blend), buttermilk (or even bottled ranch dressing), a heavy-duty zip-top freezer bag, and a straw.

  1. Butterfly the chicken breast, or pound it flat, and season.
  2. Put a butterflied chicken breast in a plastic freezer bag with the buttermilk (or ranch).
  3. Seal the bag except for one corner. Insert a straw into the remaining hole and slowly suck out the air with your mouth. Be careful not to suck the sauce into your mouth! Seal the bag to get it as air-free as possible.

Wait, what?

Sucking air out of a bag of Salmonella and Campylobacter is a terrible idea.

And have those zip-lock bags been designed to work at the unspecified higher temperature?

  1. Optional: If you are using thinner storage bags, repeat the process in a second bag, to prevent leaks.
  2. Bring a pot of water nearly to a boil. Set a piece of tin foil in the pot like a hammock (with the ends crimped over the edge).
  3. Plop the bag into the pot of hot — but not boiling — water. The foil will suspend the bag above the bottom of the pot so the bag doesn’t burn.
  4. If the chicken is thin, it will cook (poach, essentially), in five or 10 minutes. An intact chicken breast may take 20 minutes.

You can test the chicken by looking and feeling to make sure it isn’t pink inside.

Wait, what? Color is a lousy indicator. The chicken needs to be temped with a tip-sensitive digital thermometer.

I can’t wait for the next installment.

Meats are impounded as Maine chefs play with high-risk processes

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Food porn: Portland’s restaurants are on the cutting edge of the culinary renaissance in Maine, where locally sourced ingredients and inventive dishes are prized by award-winning chefs and consumers.

celebrity.chefs_-300x225But efforts by health inspectors to bring local restaurants into compliance with federal regulations and reduce the risks of a potentially dangerous foodborne illness outbreak is splashing cold water on the sizzling creativity of many area chefs – at least temporarily.

In recent months, hundreds of pounds of meat have been embargoed by health officials and are waiting in cold storage until restaurants can prove the food is safe. Several restaurants have been ordered to stop vacuum-sealing their meats, cooking sous vide dishes and offering some types of house-cured meats until they develop special hazard plans and in some cases get formal variances from the Maine Food Code.

“These are high-risk processes,” said Michael Russell, who oversees Portland’s restaurant inspection program. “In Portland, we noticed a growth in specialized processing two years ago and a significant increase in the number of establishments using these practices within the past year.”

The city’s crackdown has caught many restaurants off-guard, and there is no clear process for getting plans and variances from the state food code.

“It’s been an open secret that all of the best restaurants in Portland have been using techniques that are not approved by the FDA without variance and (special) plans,” said Brendan Murray, the head chef at Duckfat. “There is a huge amount of talent and dedication to serving the best food in the city. The level is rising rapidly and that’s a good thing.”

But do chefs know food safety?

Restaurants are required to develop special plans – called Hazard Analysis & Critical Control Points plans – for nearly 20 advanced food preparations, including vacuum-sealing, also known as reduced oxygen packaging, of raw and cooked meats on site, according to documents from the Maine Center for Disease Control and Prevention. Nine of those preparations, including pickling, curing meats and growing bean sprouts on site, also require a formal variation from the food code.

At the same time, efforts to increase the frequency and quality of Portland’s restaurant inspection program have led to cleaner, safer kitchens and more knowledgeable kitchen staffs, according to city officials and restaurant owners.

Since 2012, when the Portland Press Herald/Maine Sunday Telegram published a series of investigative reports about the city’s troubled restaurant inspection program, Portland has more than doubled the size of its inspection staff, visited restaurants more frequently and posted inspection reports online.

The paper revealed that many restaurants hadn’t been inspected for years and that, when the city hired its first health inspector in 2011, 19 out of the first 23 restaurants inspected failed – a failure rate of 82.6 percent. Since then, the failure rate has steadily improved. It was 45.5 percent in 2012 (40 out of 88 restaurants), 10.5 percent in 2013 (33 of 314) and just 6.4 percent in 2014 (31 of 482).

Restaurant owners and city officials say that’s happened because everyone is becoming more familiar with the standards.

Fake fish from plants; sous vide safety concerns?

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Alastair Bland, a freelance writer based in San Francisco who covers food, agriculture and the environment, writes for NPR that San Francisco chef James Corwell wants to “create a great sushi experience without the tuna.”

tomato.sushiTo make this Tomato Sushi, he skins and removes the seeds from fresh Roma tomatoes. Then he vacuum seals them in sturdy plastic bags and cooks them in hot water for about an hour — a technique called sous-vide.

The process firms up the tomatoes and creates a texture similar to tuna. Corwell throws in a few more ingredients (he won’t divulge what they are), and slices them up. When eaten with sushi rice, nori, ginger, soy sauce and wasabi, they’re delicious.

Corwell is not the only entrepreneur experimenting with fish-like alternatives to seafood. (His product is so far available at one retail market in San Francisco and via mail order.) But with issues like overfishing, bycatch and high mercury levels gaining traction with consumers, it may only be a matter of time before demand kickstarts a faux-fish movement on the heels of the plant-based protein revolution already underway.

Corwell of Tomato Sushi was first convinced of the need to shift away from eating the bigger tuna species after visiting Tokyo’s celebrated Tsukiji fish market in 2007. He was stunned by the hundreds of frozen bluefin carcasses sprawled across the warehouse floor.

“The way I learned to cook with big slabs of meat [and fish] isn’t going to be possible in the future, and that’s nothing to be scared of,” Corwell says.

Tuna isn’t his only focus. Corwell has created an eggplant-based rendition of unagi and a granular seasoning blend meant to taste like dried, salted bonito flakes. Through the use of fermented ingredients and yeast, caramelization and lots of stovetop test runs, Corwell says he hopes to develop many more vegan sushi products.

“[Tomato Sushi] is the just the tip of the iceberg,” he says.

Nosestretcher alert: sous vide safety in the home kitchen

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Friend of the blog Don Schaffner of Rutgers University had some food safety concerns about a recent column broadcast by state-sponsored jazz radio station NPR about sous vide – or cooking under vacuum at a specific temperature.

schaffner.facebook.apr.14She (journalist T. Susan Chang) says:

Maybe you’ve heard the stories about city health department officials forcing chefs to pour bleach on their sous vide meats. It’s a story that always makes me want to cry, but for years public health has relied on a firm food safety rule: dangerous germs live at between 40 and 140 degrees Fahrenheit. Even the pink interior of a medium-rare burger falls above this range, and most cooking techniques take place around or well above the boiling point of water (212 degrees F).

Schaffner says:

Some species of pathogenic bacteria can multiply between 40 and 140°F, and by multiply I mean increase in number. There are several species of pathogenic bacteria that can multiply slowly at temperatures less than 40°F. There are many, many pathogenic bacteria that can survive but not multiply at temperatures less than 40°F. All spore forming pathogenic bacteria can easily survive at temperatures more than 140°F. Some of these spores can survive boiling water, including the spores of Clostridium botulinum, which is of great concern because it can grow in vacuum packaged foods if the temperatures are in that 40 to 140° range for the right amount of time.

She says:

Aiming for that window — above 140 degrees for safety, below 150 degrees for texture — isn’t hard if you’re set up to control temperature within a degree or two. And you can pasteurize your protein by holding it there for long enough.

Schaffner says:

Taking food above 140°F does not make it safe. The U.S. Department of Agriculture’s Food Safety Inspection Service has a document which provides guidance to meat processors regarding safe cooking temperatures. That document is entitled “Appendix A Compliance Guidelines For Meeting Lethality Performance Standards For Certain Meat And Poultry Products”, and is available here: http://www.fsis.usda.gov/OPPDE/rdad/FRPubs/95-033F/95-033F_Appendix_A.htm. According to this document a food at 140 °F needs 12 minutes to meet the USDA standards. That same guidance also indicates that a food can meet the standards by heating at 130°F too, just for a much longer time, and even at 150°F more than a minute is needed.

She says:

Salmon is a perfect protein on which to test your newfound control. Allow the salmon to sit in this brine in the refrigerator as you bring the water bath of your sous vide up to your target temperature (115 for rare, 120 for medium-rare).

When the water bath has reached the target temperature, remove any excess air from the zip-top bag by displacement if you’re not using a vacuum-sealed bag. Drop the salmon into the bath. It should take about 1/2 hour to come to temperature.

Schaffner says:

Not likely to result in any significant pathogen reduction.  Hitting the outside with a blowtorch will kill pathogens on the surface, but not any that are internalized.

She says:

Sous Vide Pork Belly, (when) cooked at 144 degrees for two days, the lean meat fibers sandwiched between the layers of fat stay plump and juicy.

Sous VideSchaffner says:

This will give significant pathogen reduction, but I worry about any process that takes two days.  If there is a temperature failure, that is a lot of time for risk to develop.

She says:

Sous Vide Basic Burger, bring the water bath up to 120 for rare, 125 for medium-rare. Drop the bagged frozen patties in the bath (displacing any air pockets first); the meat will take about 1 1/2 hours to get to its target temperature.

Schaffner says:

Quite risky from my perspective. Pathogens will be internalized in these burgers, and even 125°F for 1.5 hours will not give a significant reduction.

She says:

Sous Vide Herbed All-Purpose Chicken Breast, bring the sous vide water bath up to 140 degrees. … You’ll need 1 to 1 1/2 hours to cook the chicken to the target temperature.

Schaffner says:

Probably safe.

Food safety can be complicated.  While I share you passion for empowering people to innovate in the kitchen, I think it is important to get the science right, especially when it comes to food safety.

(Many thanks to Schaffner for continuing to share his infectious enthusiasm for all things microbiological – and getting it right).

The sous vide of the suburbs: Cooking Thanksgiving in the dishwasher

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Ben Raymond is an MS student at North Carolina State Universit yand self-proclaimed beer aficionado, focusing on food safety through social media, barf banter, and creating new foods.

Raymond writes:

As I wait impatiently for my girlfriend to come back from work in Boston, I’m hoping the freezing rain and sleet will hold off until later tonight. We have a three-hour drive this afternoon to Vermont, to visit my family for Thanksgiving.dishwasher

Ben Chapman forwarded me a piece from the L.A. Times blog (thanks Michele -ben) on cooking a Thanksgiving dinner in the dishwasher (because I’ve become the dishwasher-cooking-food-safety guru of our group).

If you can’t seem to keep your Thanksgiving turkey moist in the oven, you may want to try your dishwasher. Yes, people have been using the kitchen washing machine to cook proteins and fish since the 1970s, but famed chef David Burke insists you can also use it to cook the star of your Thanksgiving meal.

But before you start shoving your entire turkey in the dishwasher, Burke’s recipe calls for two boneless turkey breasts, not the entire bird. The meat and herbs are packed tightly in plastic wrap then sealed in Tupperware containers before hitting the top shelf of the dishwasher for three cycles or about 3 hours and 25 minutes.

This cooking technique is getting some play in the social mediaverse as a way to make moist, tender chicken, fish, or even beef –sort of a sous vide for the suburbs (without the thermal immersion circulator).

Earlier this fall I did a quick and dirty test of this technique in my own dishwasher. With some nifty water-proof stainless data-loggers, I’ve run few cycles in the dishwasher to see if you can safely cook various proteins. Is it a safe method? The data I’ve generated points to, unsurprisingly, sort of.

Salmon cooks nicely and reaches a safe (and tender) time and temperature combination as suggested 145° F.  Even poultry may be cooked safely in the dishwasher (at least in my home, no promises for any other setup), but only if you have expensive tools to monitor the cooking process. The data shows the proteins were held at temperatures below 165° F, but still hot enough and for sufficient time to effectively be cooked (as per FSIS’ appendix A. As a home cook, armed with a tip sensitive digital thermometer, the meat is unlikely to ever register the recommended 165° F internal temperature.

image-copyThere’s lots of variability though. Other dishwashers may be hotter than mine, or not (we have very hot water in my house, over 145° F from the tap).

All of this effort the chicken I cooked in my dishwasher was gross. It never got hot enough for the proteins to really cook and move past the rubberyish texture of raw of chicken. I like my steaks medium rare, but poultry? No thanks.  In my house we will be sticking with our traditional, yet boring, oven to roast our Thanksgiving bird.

Is sous vide cooking safe?

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Maybe Pete Snyder could weigh in.

Nah, let him enjoy retirement.

But the UK Institute of Food Research (IFR) has been undertaking research for the Food Standards Agency to establish if the cooking technique sous vide is safe. Sous vide uses lower temperatures to improve food quality and could be a step closer to being more 20100611-sous-vide-burger-12widely adopted after Institute of Food Research scientists assessed the steps needed to ensure the process is safe.

Sous vide cooking involves vacuum packing food in a plastic pouch and then heating in a water bath. Chefs are attracted to the precise nature of the temperature control, allowing innovative use of the technology to create new textures and flavours by manipulating the behaviour of food components such as proteins, starches and fats. In designing new recipes and processes, microbial safety is paramount and much data has been collected on how well food poisoning bacteria grow and survive in different foods at different temperatures. This data has been collected together and made available through ComBase, a BBSRC-supported National Capability based at IFR. Food manufacturers and academics regularly consult ComBase’s extensive database of microbial growth information.

Recently, there has been an increase in the number of sous vide foods being cooked at lower temperatures, e.g. 42°C to 70°C.Most data on microbial growth in food is based on temperatures below 40°C, with studies focusing on how bacteria grow at ambient temperatures, for example during storage. Other studies have looked at the temperatures at which bacteria are killed, usually around 55-60°C and above. Lack of information in the range of about 40 to 60°C makes it very difficult for cooks, manufacturers, regulators and enforcement officers such to calculate the lethality of such low temperature heat treatments and judge the risk of foods containing pathogens.

To address this issue Dr Sandra Stringer and colleagues at the IFR, which is strategically funded by BBSRC, have gathered the information needed to properly assess the hazards associated with lower temperature cooking. The scientists also carried out a feasibility study on extending models in the ‘Combase Predictor’ database. Specifically they investigated how much work would be needed to upgrade the ComBase database to model the hazards E. coli, Salmonella and L. monocytogenes between around 40 and 60°C. This would help ensure that the safety assessment for sous vide foods is consistent, effective and commensurate with any risk to public health.