Handbook of Meat Processing

Bacon 333

during cooking. There is no evidence that this

affects eating quality, but the exudate none-

theless adversely affects appearance during

cooking. Studies at the University of Bristol

demonstrated that the exudate had a similar

composition to drip (Sheard et al. 2001 ). It

consists mainly of water, proteins derived

from the sarcoplasm, and a relatively high

level of salt. The amount of exudate was

assessed subjectively by ranking photographs

following “ dry - frying ” or objectively by col-

lecting exudate in an ice - cooled tray during

grilling. It was demonstrated that dry - cured

bacon produced less exudate than that pro-

duced by Wiltshire cured bacon; the greatest

amount of exudate was produced by rapidly

cured bacon. Tempering increased the

amount of exudate. It was also noticed that

higher amounts of exudate resulted from pigs

with the lowest ultimate pH, with least exu-

dates at the highest pHs. Although interven-

tions to reduce the amount of exudate were

not investigated, it seems likely that improv-

ing the water - holding capacity (WHC) — by

using phosphate, for example — would lead to

less exudate.

“ Tiger Stripe ”

Modern bacon sometimes exhibits a regular

alternating pattern of light and dark bands,

which was described as “ tiger stripe ” when

it was fi rst reported (Voyle et al. 1986 ). The

alternating pattern had a regular periodicity

that seemed to coincide with the injection

EU legislation aimed at minimizing the for-
mation of potentially carcinogenic nitrosa-
mines while maintaining microbiological
safety. Concern about the use of nitrite and
nitrate in cured meats stems from research in
the 1970s showing that nitrosamines were
generated during the frying of bacon (e.g.,
Patterson et al. 1976 ) and could also be
formed in vivo in the acidic conditions
present in the stomach. Despite attempts to
fi nd safer alternatives (see Pegg and Shahidi
2000 ), nitrite continues to be used in curing,
albeit at much lower levels than those
employed 30 to 40 years ago when nitrite
levels in bacon could be as high as 1000 mg/
kg (Ingram 1971 ), well above current permit-
ted levels (Table 18.1 ).
In North America, a demand for natural
and organically cured meats has led to the use
of natural sources of nitrate (e.g., sea salt,
raw sugar, and celery) rather than using con-
ventional curing ingredients. This approach
can deliver the typical quality characteristics
expected of cured meats, provided that suf-
fi cient nitrite is formed from the nitrate
source, although, in practice, residual nitrite
levels are often less than in conventionally
cured product (Sebranek and Bacus 2007 ).

White Exudate in Cooked Bacon

Though bacon remains a popular product,
one of the frequent complaints heard about
modern bacon concerns the unsightly white
liquor that sometimes exudes from bacon

Table 18.1. Changes in maximum permitted levels of nitrate and nitrite in bacon

Legislation Ingoing amount (mg/kg) Residual amount (mg/kg)

Preservatives Regs 1979^1 200 nitrite, 500 nitrite + nitrate

Food Additives Regs 1995^2 300 nitrate 175 nitrite, 250 nitrate

Food Additives Regs 2007^3 150 nitrite and 150 nitrate *

1 Preservatives in Food Regulations 1979 (amended 1982)
2 Miscellaneous Food Additives Regulations 1995 (implementing Directive 95/2/EC)
3 Miscellaneous Food Additives & Sweeteners (Amendment) (England) Regulations 2007 (implementing Directive
2006/52/EC)

• exemptions for immersion and dry cured bacon where maximum residual amounts of 175 mg/kg nitrite and
  250 mg/kg nitrate apply