274 Chapter 14
They found that peroxyacetic acid and acidi-
fi ed sodium chlorite were less effective than
4% lactic acid against aerobes and coliforms.
They also found that activity was infl uenced
by plant location. Acidifi ed sodium chlorite
is approved by the USDA for poultry and
red meat applications at 500 to 1200 ppm
(21CFR173.325).
Phosphates are known to inhibit spoilage
microorganisms (Marshall and Jindal 1997 ;
Kim and Marshall 1999 ). Castillo et al.
(2005) showed that a 7.6% trisodium phos-
phate dip reduced initial aerobic mesophilic
count of chicken wings by 1.5 log 10 CFU/g,
resulting in a shelf life extension of 2 to 3
days during storage at 4 ° C. Numerous other
investigations showed mixed results for tri-
sodium phosphate effectiveness, both against
meat spoilers and pathogens (Ismail et al.
2001 ; Lin and Lin 2002 ; Pohlman et al.
2002 ; Fabrizio and Cutter 2005 ; Ö zdemir
et al. 2006 ; del Rio et al. 2007 ). Because
trisodium phosphate requires high concen-
trations for effectiveness, the resultant cost
and soapy meat surface and fl avor may limit
its use.
Ozone is a highly oxidative gas that easily
decomposes (especially under UV light) to
produce oxygen. Ozone is on the FDA GRAS
list and its current use in meat processing is
limited to water and surface sanitizer (oxida-
tive power) and degreaser roles. According
to Lazar (2006a) , the ability of ozonated
water to both continuously clean and sanitize
eliminates the need for a sanitation shift
break during production, making meat pro-
cessing plants productive 24/7. Several
researchers investigated the possibility of
using ozonated water to decontaminate meat
(Kim et al. 1999 ; Castillo et al. 2003 ;
Kalchayanand et al. 2008 ), although most
agree that a major drawback is its ineffective-
ness in the presence of organic matter (Moore
et al. 2000 ). The inactivity of ozone in the
presence of organics and its short half - life
makes meat decontamination diffi cult. Thesenoticed that aerobically displayed nisin -
lysozyme treated meat spoiled sooner than
untreated meat. They attributed this to inhibi-
tion of lactic acid bacteria and a resultant
shift to putrefactive bacterial spoilers. In
summary, a combined lysozyme/nisin/EDTA
mixture may be a promising tool for exten-
sion of the shelf life of anaerobically pack-
aged meats by inhibiting lactic acid bacteria,
which is the predominant bacterial spoilage
group capable of growth in such conditions.
Other Antimicrobials
There are a few other novel antimicrobial
agents that have been reported to eliminate
food - borne pathogens and prevent meat
spoilage. Examples include acidifi ed sodium
chlorite, trisodium phosphate, ozonated
water, and electrolyzed water. Acidifi ed
sodium chlorite solution is a mixture of
sodium chlorite and a GRAS food - grade
organic acid. A chemical reaction between
the two produces chlorous acid, which is the
main active agent. Numerous studies have
shown acidifi ed sodium chlorite activity
against L. monocytogenes, S. aureus, Bacillus
cereus, Salmonella Enteritidis, E. coli , C.
jejuni , and Yersinia enterocolitica (Castillo
et al. 1999 ; Beverly et al. 2006 ; Ö zdemir
et al. 2006 ; del Rio et al. 2007 ). Bosilevac
et al. (2004b) evaluated the infl uence of
300 ppm acidifi ed sodium chlorite spray in
50/50 and 90/10 lean beef trimmings and
ground beef made from those trimmings on
aerobic plate count. They found that acidifi ed
sodium chlorite was most effective on
50/50 lean trimmings, reducing counts by
1.1 log 10 CFU/g. Counts in ground beef chubs
were reduced by 1.0 to 1.5 log 10 CFU/g until
day 20 at 2 ° C, while maintaining acceptable
sensory ground beef quality. Gill and Badoni
(2004) compared 0.02% peroxyacetic acid,
0.16% acidifi ed sodium chlorite, 2% lactic
acid, and 4% lactic acid on the natural fl ora
of beef brisket from two slaughtering plants.