Food Safety with Cured or Smoked Meats

[jsolomon]

Pounce, I understand where you're coming from. But, the reality of UVC compared to the promise leaves some to be desired. First and foremost, the lamps tend to lose their ability rather quickly, they tend to have an effective lifespan of about 3 months.

Also, if you have an uneven surface, shadows cast remove the effectiveness of the UVC. And, there are organisms that produce biofilms that are resistant to UVC. Plus, if you have the light on while you're curing, you'll actually burn the outside of the item, and it won't be as palatable.

[dougal]

... And for your question, tristar, temperature is very important.  That's why refrigeration was such a revolution.  The better you can control the temperature, the better things will turn out.

←

It's just that we carry out our innoculation at elevated temperatures for an extended period of time, I would have assumed that as our ph decreased and our cured sausages dry they would become more resistant to bacterial growth rather than less.

Michael himself says in the book that humidity control is more important than temperature control I believe. I was just curious about how important temperature control is, as I said in my original post the locally dried meats are dried in the sun, and in South Africa Biltong is dried without the benefits of refrigeration!

←

Richard, I think you are over-interpreting the single sentence in Michael Ruhlman's Charcuterie book (P 175) "Humidity is the critical factor and the one most difficult to control."

It is critical, but I understand that is even more important that the temperature be "cool", certainly much cooler than your 30C (86F) ambient.

Just how cool isn't terribly critical (as long as it is cool). Exactly how humid *is* critical.

My understanding is cheerfully simplistic.

Things aren't 'cured' (preserved) until the curing is finished.

I think your understanding of the different functions of the curing components may be a little off.

The acidification (from the incubated culture) and the Prague Powder (Nitrate and Nitrite) is about (taste and colour considerations apart) protecting primarily against Botulism. Not *all* the other possible nasty wee beasties that can 'spoil' the meat.

Most of the others can be dealt with by raising the concentration of salt in the meat. Much of the raising of the salt concentration is done by water removal, drying.

*After* enough water has been removed, what remains is too salty for the majority of moulds and bacteria. So the meat is preserved. Yet it remains somewhat soft and very slightly moist.

But *until* enough water has gone, during the days, weeks or months of curing (pepperoni, salami or whole hams) - you need to look after it. Not least by keeping it cool.

The brief excursion to "warm" temperatures for culture incubation is a necessary evil of that process (although there are other ways of acidifying salami). Warmth encourages all sorts of stuff to flourish - which is why you wouldn't eat it until its dried enough, to be salty enough to kill them off.

I think the comparison with Biltong is plain false.

That ends up as a *very* dry product. Brittle. Would you want salami that dry?

Biltong is a *dried* as opposed to an *air-cured* product.

Different process. Different result.

Its best not to divert this particular thread by discussing the 'how' of practical climate control!

[pounce]

Pounce, I understand where you're coming from.  But, the reality of UVC compared to the promise leaves some to be desired.  First and foremost, the lamps tend to lose their ability rather quickly, they tend to have an effective lifespan of about 3 months.

Also, if you have an uneven surface, shadows cast remove the effectiveness of the UVC.  And, there are organisms that produce biofilms that are resistant to UVC.  Plus, if you have the light on while you're curing, you'll actually burn the outside of the item, and it won't be as palatable.

←

Sure. Just trying to offer more options and interesting alternatives. In an empty all white fridge with a lot of light I doubt you get any shadows with all the refected light. If you use the lights for the calculated amount of time every so often you get a lot of life out of them. You'd have to figure out the strength of your bulbs, distance and the types of bugs you want to kill at 254nm to establish an exposure time (example: With 12 watts of UVC you can kill e. coli in ~3 seconds at 2" distance) . True, the lights could discolor the food with long exposures. I haven't tried and I have no idea what the results would be except you wouln't get any mold on them A little exposure might be useful. I guess a person would just have to experiment.

I don't want to debate the reality of UVC. It's a well proven method of sterilization. Like I said it's possibly an alternative or complimentary method for getting things clean. I think you have a lot more experience and knowledge on the food safety topic than I so I'll go back to lurking.

[tristar]

... And for your question, tristar, temperature is very important.  That's why refrigeration was such a revolution.  The better you can control the temperature, the better things will turn out.

←

It's just that we carry out our innoculation at elevated temperatures for an extended period of time, I would have assumed that as our ph decreased and our cured sausages dry they would become more resistant to bacterial growth rather than less.

Michael himself says in the book that humidity control is more important than temperature control I believe. I was just curious about how important temperature control is, as I said in my original post the locally dried meats are dried in the sun, and in South Africa Biltong is dried without the benefits of refrigeration!

←

Richard, I think you are over-interpreting the single sentence in Michael Ruhlman's Charcuterie book (P 175) "Humidity is the critical factor and the one most difficult to control."

It is critical, but I understand that is even more important that the temperature be "cool", certainly much cooler than your 30C (86F) ambient.

Just how cool isn't terribly critical (as long as it is cool). Exactly how humid *is* critical.

My understanding is cheerfully simplistic.

Things aren't 'cured' (preserved) until the curing is finished.

I think your understanding of the different functions of the curing components may be a little off.

The acidification (from the incubated culture) and the Prague Powder (Nitrate and Nitrite) is about (taste and colour considerations apart) protecting primarily against Botulism. Not *all* the other possible nasty wee beasties that can 'spoil' the meat.

Most of the others can be dealt with by raising the concentration of salt in the meat. Much of the raising of the salt concentration is done by water removal, drying.

*After* enough water has been removed, what remains is too salty for the majority of moulds and bacteria. So the meat is preserved. Yet it remains somewhat soft and very slightly moist.

But *until* enough water has gone, during the days, weeks or months of curing (pepperoni, salami or whole hams) - you need to look after it. Not least by keeping it cool.

The brief excursion to "warm" temperatures for culture incubation is a necessary evil of that process (although there are other ways of acidifying salami). Warmth encourages all sorts of stuff to flourish - which is why you wouldn't eat it until its dried enough, to be salty enough to kill them off.

I think the comparison with Biltong is plain false.

That ends up as a *very* dry product. Brittle. Would you want salami that dry?

Biltong is a *dried* as opposed to an *air-cured* product.

Different process. Different result.

Its best not to divert this particular thread by discussing the 'how' of practical climate control!

←

Thanks for that Dougal,

Your point about Biltong is quite correct, I hadn't thought about that, the same applies to the locally produced meats here in Indonesia. But I think I have to read more about this as the curing seems to me to be done at the initial stages, and there after the process is just drying isn't it? I have to find information which goes deeper into the science of this process rather than just the craft! I guess thats the problem with being an Engineer, I really have to understand the process before I am happy with it.

Best Regards,

Richard

[Doc-G]

Hi people,

As part of my job involves being an internal food safety auditor in a meat factory, one of the biggest causes of concern is cross contamination. In the case of meat products this means handling raw meat and then handling cooked, smoked or fermented products, allowing bacteria from the raw meat to 're-infect' the cured meat where the bacteria have been killed off.

With regards to your various molds, whilst I cannot comment on specific cases on this site, I have it on good authority that the only stuff NOT to worry about is the white stuff. Anything green and especially anything black is to be turfed out. However, I am not an expert on mold. There may well be some white mold that could wipe out the entire population of the planet.

Finally, checks and measures for good practices should always be carried out with preparation, especially with regards to temperature. Until smoking, curing or fermentation takes place, meat should be stored at 4 degrees centigrade or less.

Before curing, smoking or fermentation takes place, products should be weighed and then subsequently weighed again after the product has been 'cooked'. This is especially important when fermenting meat products. As a rule of thumb, it is important that the product loses around 10-15% of its weight in the first 24 hours of fermenting when using a starter culture. This is to ensure that the starter culture has activated and that sufficient amounts of lactic acid have been produced to bring down the pH levels. The by product of this is water loss and a reduction in what is called water activity obviously as well as the general destruction of much of the harmful bacteria due to the reduced pH. During this initial 24 hour time period, in order to maintain maximum moisture loss, the product must be kept in warm and MOIST conditions to prevent case hardening which can cause the product to rot (I generally squirt water over my products every two hours for the first 12 hours). After this, the product is placed in room temperature but relatively DRY (compared to the 1st 24 hours) conditions until the product weight has been reduced by around 25%. Generally speaking for a batch of salami, this takes around 4 weeks. Further hanging will produce better flavour in your product as a result of maturation.

Whilst this list is not exhaustive, I think it gives a couple of the more important pointers to pay attention to. Also, please do not treat this as advice on how you MUST make your smallgoods. If you want further clarification, check out texts or regulatory websites. A good Australian website is www.foodstandards.gov.au

I hope this is of help. I dont take any responsibility for your actions as a result of my post. Sorry about all the disclaimers. I cant claim to know everything about everything.

Cheers,

Doc-G

[tristar]

After this, the product is placed in  room temperature but relatively DRY (compared to the 1st 24 hours) conditions until the product weight has been reduced by around 25%.

←

Hi Doc-G,

So as long as we have a cured product it is ok to dry at elevated temperatures? and just out of curiosity what would you consider to be room temperature? I ask this because I live in the tropics.

This seems to contradict what I have read to be the norm that the salami should be held cold. Would the Australian government website you quoted have any more information on this? I will admit that it makes sense to me but I have no specialised food hygiene, or biological training! But being an engineer like to know and understand the process that my food is going through when I am producing it.

Regards,

Richard

[Doc-G]

After this, the product is placed in  room temperature but relatively DRY (compared to the 1st 24 hours) conditions until the product weight has been reduced by around 25%.

←

Hi Doc-G,

So as long as we have a cured product it is ok to dry at elevated temperatures? and just out of curiosity what would you consider to be room temperature? I ask this because I live in the tropics.

This seems to contradict what I have read to be the norm that the salami should be held cold. Would the Australian government website you quoted have any more information on this? I will admit that it makes sense to me but I have no specialised food hygiene, or biological training! But being an engineer like to know and understand the process that my food is going through when I am producing it.

Regards,

Richard

←

Hi Tristar,

Youve raised an important point. We live in Adelaide, Australia which is described as having a 'Mediterranean' climate. That is hot dry summers and relatively cold dry (wetter than summer of course) winters. We also generally restrict out smallgoods making to the winter months. Therefore, room temperature to us is around 12-18 degrees centigrade during the day and perhaps as low as 6-10 degrees centigrade at night.

I would assume that living in the tropics will present it's own challenges to curing at 'room temperature'. I'm not quite sure how to help you there. I would assume that your room temperature may be just perfect for the initial 24 hour cure to activate the starter culture. The maturation process however will be an interesting prospect for you as you will have to maintain a lower temp and humidity for longer periods of time. As for how to go about, someone else will have to help you here.

There are some pretty clever people on this board! I'm sure someone will think of something!

Cheers,

Doc-G

btw from memory the website I previously mentioned does have a fair amount of information on food safety for meat manufacturing.

Edited July 11, 2006 by Doc-G (log)

[tristar]

After this, the product is placed in  room temperature but relatively DRY (compared to the 1st 24 hours) conditions until the product weight has been reduced by around 25%.

←

Hi Doc-G,

So as long as we have a cured product it is ok to dry at elevated temperatures? and just out of curiosity what would you consider to be room temperature? I ask this because I live in the tropics.

This seems to contradict what I have read to be the norm that the salami should be held cold. Would the Australian government website you quoted have any more information on this? I will admit that it makes sense to me but I have no specialised food hygiene, or biological training! But being an engineer like to know and understand the process that my food is going through when I am producing it.

Regards,

Richard

←

Hi Tristar,

Youve raised an important point. We live in Adelaide, Australia which is described as having a 'Mediterranean' climate. That is hot dry summers and relatively cold dry (wetter than summer of course) winters. We also generally restrict out smallgoods making to the winter months. Therefore, room temperature to us is around 12-18 degrees centigrade during the day and perhaps as low as 6-10 degrees centigrade at night.

I would assume that living in the tropics will present it's own challenges to curing at 'room temperature'. I'm not quite sure how to help you there. I would assume that your room temperature may be just perfect for the initial 24 hour cure to activate the starter culture. The maturation process however will be an interesting prospect for you as you will have to maintain a lower temp and humidity for longer periods of time. As for how to go about, someone else will have to help you here.

There are some pretty clever people on this board! I'm sure someone will think of something!

Cheers,

Doc-G

btw from memory the website I previously mentioned does have a fair amount of information on food safety for meat manufacturing.

←

Thanks Doc,

I think until I find definitive information I will just keep using the old fridge! But I may just leave a test sample out and see if it spoils and how long it takes to do so.

Regards

Richard

[edsel]

I've been watching this thread with great interest - it appeared with perfect timing (thanks Chris!). I was actually considering starting one myself, given all the questions we all have on the Charcuterie thread....

I've been making fresh sausage and such for years. Despite my love of cured meats (especially dry-cured hams), I always chickened out when it came to hanging meat to cure at warmer temperatures. Thanks to the Ruhlman/Polcyn book and the eG "curing from" thread, I finally started curing guanciale, bacon, pancetta, and bresaola in my basement. The results ranged from OK to really great.

In early June I attended a benefit dinner for our Ohio Terra Madre delegates (see the heartland forum). Among the guests of honor were some folks from Heritage Foods. OK, here's where I went a little nuts. Inspired by all the good things the Heritage Foods USA farmers are doing, I ordered a Red Wattle ham (bone in) to be delivered in early June. I chose the Red Wattle breed because it's supposed to have an especially flavorful ham. I've since read that the hams from Parma and the Veneto are from breeds similar to the Duroc, but the Red Wattle just sounded really cool. My basement was hovering in the mid-sixty range (Fahernheit), so I figured I could hang the ham there to age.

I've got the ham curing in my refrigerator. I followed the recipe in Paul Bertolli's book since he uses nitrate in addition to salt. Yeah, I know that it's less authentic than Italian Prosciutto or jamon Iberico, but I'm feeling a bit paranoid. Actually, the nitrate is the only thing in Bertolli's recipe that seems to deviate from the Italian tradition.

No sooner had I ordered the ham than the temperature started creeping upwards in my basement. I belatedly realized that August is not the best month to hang a ham. Too late for buyer's remorse. So I've got a Red Wattle ham crusted in salt curing in my refrigerator.

To further confuse matters, there seems to be some disagreement about the safe temperature for dry-curing ham. I've seen instructions for hanging the ham in a kitchen. There's a Virginia Tech page on dry cured Virginia ham that says you can age the ham for 45-180 days at 75-95°F and a relative humidity of 55-65%. My basement never gets that warm!

I think until I find definitive information I will just keep using the old fridge! But I may just leave a test sample out and see if it spoils and how long it takes to do so.

Regards

Richard

←

Richard, I saw your post about your lamb "pancetta" in the Charcuterie topic. So did you cure it entirely in the fridge? I find your adventures especially encouraging. I lived in Jakarta some years ago (so many that I want to spell it "Djakarta" ) Believe me, the humidity in Ohio never approaches what you're experiencing there!

[tristar]

Hi Edsel,

As these were my first adventures into the world of curing and drying I did dry the lamb "Pancetta" in the fridge.

However I am very tempted to try some dry cured meats in the ambient conditions here in Jakarta, I am sure that they would develop a character of their own, as long as I can hold the bad bacteria at bay! There is a local dried meat called deng-deng which is beef, cured with palm sugar and coriander and that is dried in the sun, there are also a number of soy products, such as tempeh and oncom which are fermented at elevated temperatures for a few days, the oncom is actually very interesting as it blooms into a very bright orange colour and has a mushroomy flavour! I am thinking along the lines of preparing a peperone style sausage and innoculating it with the oncom mould and seeing where it takes me!

I think I trust my senses to keep me free from harm, there should be plenty of oxygen available to prevent botulinum bacteria from multiplying, and any other spoilage should be sensed by smell or taste. Anyway where would we be if nobody took any risks?

This will all have to wait a few weeks as I am currently in Central West Africa far from the comfort of my kitchen at home!

If the experiment takes place it will be documented and posted in eGullet so just keep your fingers crossed!

Best Regards,

Richard

[dougal]

...

To further confuse matters, there seems to be some disagreement about the safe temperature for dry-curing ham. I've seen instructions for hanging the ham in a kitchen. There's a Virginia Tech  page on dry cured Virginia ham that says you can age the ham for 45-180 days at 75-95°F and a relative humidity of 55-65%. My basement never gets that warm!

...

←

Woooaaaaaa!

Edsel, confusion will be created if people take things out of context.

Read that Virginia page carefully.

The instructions are

{Apply the cure.} Virginia style hams should be cured 7 days per inch of cushion depth (Figure 3A - How to Identify a Quality Fresh Ham), or 11/2 days per pound of ham. Keep accurate records of placing hams in cure. Also, write the date to remove hams from cure on the calendar as shown.

Early December is the best time to start curing Virginia style hams under ambient conditions.

During the curing period, keep hams at a temperature of 36° - 40°F.

So for a big 15+ pound ham - we are talking almost a month BELOW 40ºF in cure.

So if you are hoping to cure under ambient conditions, start in mid-winter, and make sure your ham isn't too big, so it can be cured before the temperature exceeds 40ºF...

Then for a bit more preservation they smoke it...

The fire should be a "cool" smoldering type which produces dense smoke. The temperature of the smokehouse should be kept below 90°F. Hams should be hung in a smokehouse* so that they do not touch each other. They should be smoked until becoming chestnut brown in color, which may take 1-3 days.

3 DAYS in *dense* smoke below 90ºF. That *is* smoked.

And *only* then

Age hams for 45-180 days at 75-95°F and a relative humidity of 55-65%.

So that is

- *cure* it for *weeks* *below* 40ºF

- then heavily *smoke* it in dense cool smoke for 3 days

- and then *AGE* it at Virginia *summer* ambient temps

It is extremely misleading to leave the suggestion that Virginia Tech are proposing dry-curing at 75-95ºF. They are not.

I don't think any authority has ever suggested that dry-curing can be successful at above perhaps 60ºF. Virginia Tech are specifying below 40ºF.

As far as bugs and biochemistry are concerned, what matters is the actual temperature, not whether that happens to be indoors, outdoors, in a kitchen or a barn. Although it might seem unbelieveable to modern americans, 60ºF might have been a typical winter "kitchen" temperature for a peasant farmer in a mountainous area of Europe, perhaps even up to the present day.

The one difference between a specified temperature and humidity in different locations is going to be the amount of air movement (which can have a great influence on evaporation/drying rates at the same temperature and humidity). Some air movement is a good thing, to even out the humidity and prevent any 'pockets' being in the higher humidity ranges that favour mould growth.

There are good reasons that the tradition of dry-curing under ambient conditions only exists in some geographical locations, and during particular climatic seasons.

The fortunate thing for us, in the modern age, is that "climate control" is a technological possibility for an enclosed space, and it's use can allow activities like dry-curing, and cheese-making, to be practiced year-round all over the world.

Edited July 19, 2006 by dougal (log)

[tristar]

There are good reasons that the tradition of dry-curing under ambient conditions only exists in some geographical locations, and during particular climatic seasons.

I think I may be about to throw the cat amongst the pigeons, but.....

Urutan is a Balinese traditional dry fermented sausage prepared from lean pork and various kinds of spice. Urutan is different from the European sausages, because it is fermented under warm condition with fluctuating temperatures of approximately 25 degrees C at night to 50 degrees C during sun drying. In this study, two of the 71 strains of lactic acid bacteria (LAB) isolated from natural urutan fermentation were used as starter cultures: Lactobacillus plantarum U201, the dominant LAB, and Pediococcus acidilactici U318, a bacteriocin producer. A soft urutan with yellowish brown color was produced using these strains as multiple starters. The starter cultures grew in characteristic succession which reconstructed the natural fermentation process. Lactobacilli were dominant until 48 h fermentation and pediococci dominated at the later stage of fermentation. Proliferation of starter cultures produced lactic acid which resulted in the decrease in pH and coagulation of soluble protein in urutan. Both strains could eliminate the Enterobacteriaceae in urutan after 24 h fermentation, and could suppress and eliminate the occurrence of micrococci at 120 h fermentation. By using a single starter culture, no succession was observed to occur in urutan and the time of elimination of Enterobacteriaceae was delayed. Thus, the strains of L. plantarum U201 and P. acidilactici U318 have great potential for use as multiple starter cultures in urutan fermentation

Effects of indigenous starter cultures on the microbial and physicochemical characteristics of Urutan, a Balinese fermented sausage.

I think I will be trying it when I get home.

[tristar]

Well,

I did try it and the results were superb, the dried sausage was not at all sour as is the case in some Thai fermented sausages, but they were very hot and spicy, super as an addition to fried rice. And all without the addition of starter culture. I am assuming that the combination of spices acted as an anti bacterial and anti fungal.

Well at least I lived to tell the tale!

Urutan Bali