3. Curing agents

1
3. Curing agents

• Nitrite (sodium or potassium)..
• and sometimes nitrate

• functions only by conversion to nitrite first
• useful only in dried products such as dry
  sausage or country cured/prosciutto hams
• 7 lbs per 100 gal of pickle 3 1/2 oz per
  100 lbs meat for dry cure 2 3/4 oz per 100
  lbs of meat when used for chopped
• when nitrate is used, microbial conversion to
  nitrite is required
• Micrococcus sp. (now Kocuria sp.) have catalase
  to convert NO3- to NO2-
• sometimes included in starter cultures as a
  cured color promoting agent
• now part of naturally cured products labeled
  Uncured!

2
definitely magic - distinctive, absolutely no
substitute
Nitrite

• permitted at 2 lbs per 100 gal of pickle (10
  pump) 1 oz. per 100 lbs of meat for dry cure
  1/4 oz per 100 lbs of chopped meat. Cannot
  exceed 200 ppm in finished product
• except bacon ? 120 ppm nitrite plus maximum
  (550 ppm) ascorbate or erythorbate
• defines a cured product --- almost always
  includes salt as well when cured
• not permitted in baby foods (sterilized)

3
Functions of nitrites (NO2-) in curing

• 1. color
• due to nitric oxide (NO) from nitrite NO2-
• promoted by acid conditions
• accelerated by reductants, pigments (Fe) and salt
• 2. microbial inhibition
• very effective against Clostridium botulinum but
  is inhibitory toward many organisms both
  pathogens and spoilage organisms

4
(No Transcript)
5
3. antioxidant

• very effective for preventing rancidity -
  particularly preblends

6
(No Transcript)
7
4. flavor

• likely produces a unique cured flavor but this
  has never been chemically identified
• 5. texture
• nitrite reacts with sulfur-containing amino acids
  to form crossbridges between proteins

8
So an absolutely critical step in meat curing
is forming nitric oxide (NO) from
nitrite (NO2-)

• Conditions which increase nitric oxide
  formation
• 1. pH
• 2NO2- 2H ? 2HONO ? NO NO3-
  2H
  nitrous acid nitric oxide
  nitrate
• decreases pH by 0.2 - 0.3 pH will double the
  production rate of NO
• may add sodium acid pyrophosphate or glucono
  delta lactone

9
2. reductants

• sodium ascorbate or erythorbate, ascorbic acid or
  erythorbic acid
• react directly with nitrite to produce nitric
  oxide

10
3. meat pigments

• myoglobin-Fe NO2- ?
  myoglobin-Fe NO

reductants myoglobin-Fe
? myoglobin-Fe

NO NO
11
4. proteins

• sulfhydryl amino acids

SH
S
NO2-
NO
S
SH
12
5. salt

• NaCl NO2- ? NOCl- ? NO
  Cl-

13
Nitrite is very reactive and reacts with many
things in a meat system

• most are positive reactions
• --- but ---
• nitrite can also react with secondary amines
• NH NO2 ? N NO nitrosamine

• a definite carcinogen at ppb concentrations
• formerly a problem in bacon

14
Nitrosamines are controlled by

• low residual nitrite when bacon is fried
• presence of reductants to encourage other nitrite
  reactions

15
Related problem with rubber nettings used to hold
hams for smoking

• butyl-amine in rubber reacted with nitrite in
  hams to produce butylnitrosamine

16
Concerns for nitrite

• a. toxicity
• very reactive, toxic
• lethal dose is about 1 g (14 mg/kg body weight)
• relaxes smooth muscle and reduces blood pressure
• methemoglobinemia
• human exposure to nitrite/nitrate is about 80
  -vegetables, 10-15 - water, 5 or less - cured
  meat
• ingested nitrate is absorbed and secreted in
  saliva ( 25 of that is absorbed) and about
  20 of that is converted to nitrite by oral -
  cavity microorganisms
• must maintain records of use for USDA when making
  products

17
most processors use Modern Cure, Prague
Powder, Legg Cure - brand names for
curing mixture 6.25 sodium nitrite
93.75 sodium chloride
pink dye

• because
• pure nitrite is a white crystal very similar to
  sodium chloride
• Germany and European Community countries do not
  permit use of pure nitrite, only salt/nitrite
  mixtures
• b. nitrosamine formation
• controlled by controlling residual nitrite

18
Sidelight

• nitric oxide has become an important topic in
  human physiology
• involved with brain cell communications, control
  of smooth muscle contraction and immune system
  attacks on invading bacteria

19
Non-meat ingredients

• 4. Reductants
• sodium ascorbate or erythorbate,
• permitted up to 7/8 oz per 100 lbs (550 ppm)
  87.5 oz per 100 gal pickle (10 pump)
• ascorbic acid or erythorbic acid
• permitted at 3/4 oz per 100 lbs of meat 75 oz
  per 100 gal of pickle (10 pump)
• ascorbate/erythorbate most common because acid
  forms can be too reactive with nitrite
• ascorbic acid, ascorbate ? Vitamin C
• erythorbic acid, erythorbate - optical isomer,
  not biologically active
• ascorbate/erythorbate are equivalent in terms of
  meat curing

20
Primary function is to increase nitrite curing
reaction

• NO2- ? NO
• but also helps to maintain cured color during
  storage (reductant)
• 10 solution may be used to spray surface of
  cured products prior to packaging - treatment
  cannot result in significant added water
• very effective for improving stability of fresh
  meat color but not permitted --- too effective!

21
Reductants

• for brines/injection curing
• should be dissolved immediately after the
  phosphates --- otherwise may remain undissolved
  and result in weak or uneven curing reactions
• brines for injection should be made up
• 1. phosphates
• 2. ascorbate/erythorbate
• 3. salt, sugar, etc.
• 4. nitrites

22
(No Transcript)
23
Non-Meat Ingredients

• 5. Acidulants
• acid compounds to reduce pH and accelerate nitric
  oxide (NO) production --- trade-off with WHC
• objective is 0.2-0.3 pH change
• also permitted as spray to improve peeling of
  frankfurters (5 citric acid or 35-40 grain
  vinegar)

24
For cure acceleration

• 1. sodium acid pyrophosphate (SAPP)
• acid phosphate
• permitted at 0.5
• 2. glucono delta lactone (GDL)
• permitted at 0.5 as a cure accelerator
• may also be used at up to 1 in dry sausage to
  simulate fermentation

25
Acidulants may also be added in encapsulated form
for slow release to simulate fermentation

• lactic acid or citric acid