64 Chapter 3
“ available ” chlorine is decreased by organic
material (due to oxidizing - reducing reac-
tions), while effectiveness is reduced at low
temperatures, and it is highly affected by the
pH of the solution, with maximum activity
in the 6.0 – 7.0 range (Oomori et al. 2000 ;
Edwards and Fung 2006 ; Kalchayanand et al.
2008 ).
Chlorine dioxide (ClO 2 ) is an alternative
to chlorine, which is effective in controlling
the natural fl ora occurring in poultry chill
water, with no interference of pH (Tsai et al.
1995 ). However, it is not more effective in
reducing microbial contamination on car-
casses than chlorine or spraying with water
alone (Cutter and Dorsa 1995 ; Stopforth
et al. 2007 ). Furthermore, given the lack of
information related to potential health risks
of ClO 2 (Tsai et al. 1995 ), it has not been
commercially applied as a decontaminant on
beef, but, as indicated, it fi nds use in poultry
chill tank water as well as vegetables.
Other chemical agents containing various
forms of chlorine, such as 500 – 1200 ppm
acidifi ed sodium chlorite (ASC) and 100 mM
sodium chlorate, have been shown to reduce
bacterial pathogens, APC, and TCC in chilled
meat or poultry carcasses and meat cuts
(Kemp et al. 2000 ; Anderson et al. 2001 ; Gill
and Badoni 2004 ; Lim and Mustapha 2004 ;
Stopforth et al. 2007 ). Preliminary in vitro
studies showed that 20 mM of a commercial
sodium chlorite - based oxyhalogen disinfec-
tant (Salmide ® ) caused 3 – 5 log 10 CFU/cm^2
reductions of E. coli O157:H7, Salmonella,
and L. monocytogenes in aqueous solutions,
whereas when combined with ethylenediami-
netetracetic acid (EDTA) the observed reduc-
tions were > 6 log 10 CFU/cm^2 (Mullerat et al.
1995 ). Spraying of beef carcass samples with
ASC (1200 ppm for 10 s at 69 kPa at 22 –
24 ° C) activated with phosphoric or citric acid
(fi nal pH 2.5 – 2.9) decreased inoculated E.
coli O157:H7 and S. Typhimurium counts
by 4 to 5 log 10 CFU/cm^2 and L. monocyto-
genes and S. aureus counts by 1 – 1.9 log 10
CFU/cm^2 (Castillo et al. 1999b ; Lim andIn conclusion, lactic acid spray rinses up
to 5% to constitute an effective decontamina-
tion intervention for both immediate reduc-
tion of microbial contamination on carcass
surfaces and meat as well as inhibition of
growth in packaged meat. Application of
lactic acid after water - washing is recom-
mended in order to ensure long - term antimi-
crobial effects. Nonetheless, excessive use of
organic acids may result in corrosion of meat
processing equipment (Theron and Lues
2007 ). Currently, lactic acid decontamination
is widely used in U.S. beef slaughtering
plants.
Other Chemical Solutions
Chlorine is a well - known sanitizing agent,
which is commonly used in the food industry
for sanitation of equipment, utensils, and
water supplies (Sofos and Smith 1998 ). It can
also be added in the water used for fi nal
washing or chilling of carcasses. Chlorine
solutions (20 – 50 ppm) applied at 4 – 23 ° C
reduced presence of Salmonella and Cam-
pylobacter on chicken carcasses by 56% and
12%, respectively (Kelly et al. 1981 ; Tsai
et al. 1995 ; Sofos and Smith 1998 ; Whyte
et al. 2001 ; Park et al. 2002 ; Fabrizio et al.
2002 ; Stopforth et al. 2007 ; Bauermeister
et al. 2008 ). On beef, the bacterial reductions
achieved by 50 – 900 ppm chlorine (pure or
electrolytically generated), or 200 – 500 ppm
of acidifi ed chlorine are of similar magnitude
to those caused by water - washing (Emswiler
et al. 1976 ; Kochevar et al. 1997b ; Bosilevac
et al. 2005 ). Effectiveness of chlorine treat-
ments may be enhanced at high (74 ° C) com-
pared to low (16 ° C) washing temperatures
(Kochevar et al. 1997b ). However, chlorine
is considered a less effective decontamina-
tion agent than organic acids (Acuff 2005 ;
Edwards and Fung 2006 ), whereas concerns
have been expressed for corrosion of equip-
ment, formation of harmful by - products
when reacting with organic matter, and oxi-
dation of meat color and lipids. Indeed,