Handbook of Meat Processing

Curing 137

around 90%. In products with access to

oxygen, the remaining concentrations are

by far lower than 90% (see Tables 6.5 , 6.6 ,

and 6.8 ).

Nitrosamine Formation in

Meat Products

In the 1970s in the United States, a discus-

sion arose about the formation of nitrosa-

mines in cured meat products, especially

fried bacon. Fiddler et al. (1978) showed that

bacon and its cookout on frying contained

considerable amounts of nitrosopyrrolidine.

According to the reactions shown in

Figure 6.13 , nitrosamines are formed by

amines with nitrite at higher temperatures.

But there are some prerequisites for the

sequence of reactions to nitrosamines to

occur.

• Amines must be present. In fresh meat
  there are very minute amounts of amines
  present, which are the decarboxylation
  products of amino acids. During aging and
  fermentation, amines will be formed.


• Only secondary amines form stable nitro-
  samines. Primary amines are immediately
  degraded to alcohol and nitrogen. Tertiary
  amines cannot react. Most amines in meat
  are primary amines derived from α - amino
  acids.

is added, is related to the nitrite content.
Figure 6.12 shows that with emulsion - type
sausages (only nitrite curing salt used), the
residual amounts of nitrite and nitrate exhibit
no relationship above 20 mg residual nitrite/
kg. There is no generally recognizable
increase of nitrate with increasing residual
amounts of nitrite. Without nitrite addition, a
residual amount of nitrate up to 30 mg/kg is
probably due to the addition of drinking
water to the batter (0 – 50 mg nitrate/l).
It is interesting to note that the application
of ultra - high pressure does change the nitrite
concentration, as the sum of nitrite plus
nitrate is > 95% at control (no pressure, no
heat in vacuo ) up to 800 MPa (Table 6.9 ).
Even after storage for twenty - one days
( in vacuo ), the sum of nitrite plus nitrate is

0

10

20

30

40

50

60

70

<10 10–20 20–40 40–60 60–80 >80

concentration of nitrite (mg/kg)

% of total

emulsion type N = 109

cooked sausage

cooked ham N = 33

raw sausage N = 43

raw ham N = 17

Figure 6.11. Nitrite concentrations in meat products. (Adapted from Dederer 2006 .)

Table 6.8. Nitrate and nitrite concentration in
German meat products 2003 – 2005 (adapted
from Dederer 2006 )

sausage type N median

nitrite

(mg/kg)

nitrate

(mg/kg)

emulsion type

sausages

91 13 24

non - heat treated

sausages

15 18 59

non - heat treated

ham

14 19 17

liver/blood

sausages

16 12 43