Arkansas - Agricultural Communication Services - University of ...

The Impact of Multiple Antimicrobial Intervention Agents
on Ground Beef Color
F. W. Pohlman, 1 M. R. Stivarius, 2 K. S. McElyea, 1 Z. B. Johnson, 1
and M. G. Johnson 3
Story in Brief
The effectiveness of multiple antimicrobial interventions on ground beef instrumental color through display was
studied. Beef trimmings were inoculated with Escherichia coli (EC) and Salmonella typhimurium (ST) then treated with
either 1) 5% acetic acid followed by 0.5% cetylpyridinium chloride (AC), 2) 200 ppm chlorine dioxide followed by
0.5% cetylpyridinium chloride (CC), 3) 0.5% cetylpyridinium chloride followed by 10% trisodium phosphate (CT) or
4) control (C). Trimmings were ground, packaged and sampled through display for instrumental color characteristics.
Ground beef from the CC treatment was similar (P > 0.05) in redness (a*) to C. The CT treatment remained (P < 0.05)
redder (a*) in color and contained more (P < 0.05) oxymyoglobin than C by day 7 of display. Ground beef from the AC
treatment was (P < 0.05) lighter (L*), less yellow (b*) and less red (a*) in color than C throughout display. Therefore,
the use of CC did not harm ground beef color whereas CT improved ground beef color by extending oxymyoglobin stability
and product redness.
Introduction
Multiple intervention technology involves the use of
different barriers such as pH changes, oxidizing environments,
or other environmental changes to cause disruption of
microbial cells or cellular metabolism, to either destroy bacterial
cells or retard their growth. Hurdle technology has been
more effective than single interventions for beef carcass
decontamination (Phebus et al. 1997). In addition, Ellebracht
et al. (1999) used 203°F hot water and 2% lactic acid multiple
interventions in the production of ground beef to reduce
E. coli, Salmonella typhimurium and aerobic plate counts 1.1,
1.8, and 1.5 log colony forming units (CFU)/g, respectively.
Through the development of multiple antimicrobial intervention
techniques Pohlman et al. (2001) was able to reduce E.
coli, Salmonella typhimirium, coliform and aerobic bacteria
in ground beef.
In addition to the effectiveness of antimicrobial treatments,
another concern is the impact of these treatments on
meat color. Treatments such as hot water, organic acids, or
other decontaminants can have an adverse effect on meat
color (Unda et al., 1989; Bell et al., 1986). Therefore, the
objective of this research was to determine the effects of multiple
antimicrobial interventions on the instrumental color of
ground beef.
Experimental Procedures
Bacterial preparation and inoculation. Inoculums were
prepared from frozen (-112°F) stock cultures of Escherichia
coli (ATCC #11775; EC) and a nalidixic acid resistant strain
of Salmonella typhimurium (ATTC 1769NR; ST). E. coli was
maintained by brain heart infusion (BHI)(Difco Laboratories,
Detroit, MI) broth with glycerol (20%) and Salmonella
typhimurium was maintained by BHI broth containing
nalidixic acid (Fisher Scientific, Fairlawn, NJ) with glycerol
(20%). Frozen cultures of E. coli and Salmonella typhimurium
were thawed, and 0.1 ml of E. coli suspension was inoculated
into separate 40 ml aliquots of BHI, and 0.1 ml of
Salmonella typhimurium suspension was inoculated into separate
40 ml aliquots of BHI with nalidixic acid. After 18
hours of incubation at 98.6°F, bacteria were harvested by centrifugation
(3649 x g for 20 min @ 98.6oF)(Beckman GS-6
series, Fullerton, CA), re-suspended in the same volume of
0.1% buffered peptone water (BPW) (Difco Laboratories,
Detroit, MI), and then pooled (1600 ml of E. coli and 1600 ml
of Salmonella typhimurium) to make a bacterial cocktail. The
cocktail (3200 ml; log 10 7 CFU/ml E. coli and log 10 7
CFU/ml Salmonella typhimurium) was cooled to 39.2°F and
combined with boneless beef trimmings (28.2 lb) and
allowed to attach for 1 hour. The meat was then drained and
separated into 7.9 lb batches and placed in a 39.2°F cooler for
12 to 14 hours to allow further microbial attachment.
Antimicrobial treatment application and sample processing.
Treatment combinations for this study included: 1)
5% (vol:vol) acetic acid solution (Shurfine Inc., Northlake,
IL) followed by 0.5% (wt:vol) cetylpyridinium chloride solution
(Zeeland Inc., Zeeland, MI)(AC); 2) 200 ppm (vol:vol)
chlorine dioxide solution (Midland Chemical Company,
Lenexa, KS) followed by 0.5% (wt:vol) cetylpyridinium
chloride solution (CC), 3) 0.5% (wt:vol) cetylpyridinium
1 Department of Animal Science, Fayetteville
2 Griffith Laboratories, Griffith Center, Alsip, IL 60658
3 Department of Food Science, Fayetteville
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