Posted: Tue Nov 04, 2014 16:42
Here you Go Ross...Compliments of El Ducko in the project KB thread:
Nitric oxide should not be confused with nitrous oxide (N2O), an anesthetic and greenhouse gas, or with nitrogen dioxide (NO2), a brown toxic gas and a major air pollutant.
The reaction of "stuff" with bacteria is so fast, and the bacterial concentration consequently is so low, that it might as well be instantaneous. This and the other consumption reactions keep the concentration of "stuff" so low that there is, for all intents and purposes, no reverse reaction. The limiting reaction rate for the whole scheme appears to be the consumption of nitrite to "stuff," which is why you can find a nitrite concentration in meat to which nitrite has been added, but no appreciable "stuff."
How much nitrite should be present, and how long will it last? Well... depends on how fast it is being used up (a function of concentration and temperature). Below about 40°F, the bacterial growth rate is slow and nitrite isn`t necessary. Between 40° and about 150°F, the bacterial growth rate is appreciable, so you need nitrite. Bacterial growth rate increases exponentially with temperature. However, above 150°, the bacteria die, so you don`t need nitrite. Wouldn`t it be cool if you could put in just enough nitrite that it could all be used up on the way from 40° to 150°?
And here's why there is no straightforward answer to your question about nitrite- - "How much is just enough...?" It depends on the temperature history of the mix. The government guidelines are there simply to allow enough nitrite that, under reasonable conditions, at least some nitrite will present up until the meat is treated to a high enough temperature to kill the "bad guys."
What if you can`t add enough to out-last the consumption reactions? This happens in fermented sausages, which must be in the temperature "danger zone" for months.(We`re "jumping the gun," here, but you had to ask!) That`s why there is cure #2. This mixture generates cure #1, if you will, producing nitrite without exceeding the maximum guideline.
There is a reversible reaction between nitrate and nitrite. Since nitrite is being consumed, its concentration declines, causing more nitrate to be converted to nitrite. Thus, nitrate keeps nitrite available longer without exceeding the guideline nitrite maximum concentration. Overall, nitrite still gets consumed, but it also gets produced so long as nitrate is present, until we run out of nitrate and nitrite both, finally reaching a nitrite concentration close to zero.
By that time, though, another protective mechanism comes into play in fermented sausages. If your processing is correct, the amount of water lost is enough ("water activity" has been reduced) that the "bad guy" bacteria cannot grow. More about fermented sausages, later. More, too, about semi-dried, cooked sausages, another technique for our arsenal.
This nitrite/drying strategy has been quite effective in safeguarding sausages of the semi-dried, smoked, cooked variety, and when coupled with nitrate, is just as effective for the fermented variety.
Nitric oxide should not be confused with nitrous oxide (N2O), an anesthetic and greenhouse gas, or with nitrogen dioxide (NO2), a brown toxic gas and a major air pollutant.
The reaction of "stuff" with bacteria is so fast, and the bacterial concentration consequently is so low, that it might as well be instantaneous. This and the other consumption reactions keep the concentration of "stuff" so low that there is, for all intents and purposes, no reverse reaction. The limiting reaction rate for the whole scheme appears to be the consumption of nitrite to "stuff," which is why you can find a nitrite concentration in meat to which nitrite has been added, but no appreciable "stuff."
How much nitrite should be present, and how long will it last? Well... depends on how fast it is being used up (a function of concentration and temperature). Below about 40°F, the bacterial growth rate is slow and nitrite isn`t necessary. Between 40° and about 150°F, the bacterial growth rate is appreciable, so you need nitrite. Bacterial growth rate increases exponentially with temperature. However, above 150°, the bacteria die, so you don`t need nitrite. Wouldn`t it be cool if you could put in just enough nitrite that it could all be used up on the way from 40° to 150°?
And here's why there is no straightforward answer to your question about nitrite- - "How much is just enough...?" It depends on the temperature history of the mix. The government guidelines are there simply to allow enough nitrite that, under reasonable conditions, at least some nitrite will present up until the meat is treated to a high enough temperature to kill the "bad guys."
What if you can`t add enough to out-last the consumption reactions? This happens in fermented sausages, which must be in the temperature "danger zone" for months.(We`re "jumping the gun," here, but you had to ask!) That`s why there is cure #2. This mixture generates cure #1, if you will, producing nitrite without exceeding the maximum guideline.
There is a reversible reaction between nitrate and nitrite. Since nitrite is being consumed, its concentration declines, causing more nitrate to be converted to nitrite. Thus, nitrate keeps nitrite available longer without exceeding the guideline nitrite maximum concentration. Overall, nitrite still gets consumed, but it also gets produced so long as nitrate is present, until we run out of nitrate and nitrite both, finally reaching a nitrite concentration close to zero.
By that time, though, another protective mechanism comes into play in fermented sausages. If your processing is correct, the amount of water lost is enough ("water activity" has been reduced) that the "bad guy" bacteria cannot grow. More about fermented sausages, later. More, too, about semi-dried, cooked sausages, another technique for our arsenal.
This nitrite/drying strategy has been quite effective in safeguarding sausages of the semi-dried, smoked, cooked variety, and when coupled with nitrate, is just as effective for the fermented variety.