Transcript Rinse & Chill Technology: Novel Intervention for Reduction

Rinse & Chill  Technology:
A Novel Intervention for Reduction of
Undesirable Bacteria on Beef
Carcasses and On-going Protection
from E. coli O157:H7 in Vacuumpackaged Ground Beef
ABSTRACT
Rinse and ChillTM Technology, developed by MPSC, Inc., St. Paul,
Minnesota involves rinsing a chilled solution of sugars and salts through the
cardiovascular system. The solution removes most of the residual blood as
it circulates throughout the carcass and drains. Rinse and ChillTM
Technology is a process, which ensures a consistent reduction in pH and
internal temperature and has been demonstrated to significantly reduce the
presence of microorganisms, particularly coliforms and generic Escherichia
coli. In addition, Rinse and ChillTM Technology provides on-going
protection for vacuum-packaged ground beef. Data collected from two
separate commercial beef slaughtering facilities demonstrated a 40.3%
(n=180; p value = 0.039) and 41.2% (n = 100; p value = 0.009) reduction for
aerobic microorganisms on rinsed carcasses when compared to controls.
More importantly, the two commercial facilities demonstrated a 99.3% (n =
180; p value = 0.125) and 67.8% (n = 100; p value = 0.002) reduction in
coliforms on the rinsed carcasses versus the controls. One of the
commercial slaughter facilities also demonstrated an 83.7% (n = 100; p
value 0.0008) reduction in generic E. coli on the rinsed carcasses versus
the controls. Research was conducted that demonstrated that vacuumpackaged ground beef made from Rinse and ChillTM carcasses provided a
4 log reduction in E. coli 0157:H7 as compared to only a 2 log reduction in
the control carcasses.
INTRODUCTION
Due to increased consumer awareness and recent changes in the regulation of
meat inspection, there has been a move by the meat industry to improve
sanitary conditions and the microbiological status of meat in slaughtering and
processing plants. In 1993, the “Zero Tolerance” policy, which requires knifetrimming for removal of all visible physical contamination from beef carcasses
prior to washing and chilling, was enacted. Since 1996, the Pathogen
Reduction/HACCP Act requires meat and poultry slaughter establishments to
implement sanitation standard operating procedures (SSOPs) and a hazard
analysis critical control (HACCP) system. The establishment of microbiological
performance criteria with standards for generic Escherichia coli and Salmonella
as a means of verification of HACCP also were implemented. These
regulations have led to more research, development and application of meat
decontamination technology with the objective of helping the industry to meet
or exceed regulatory requirements, and to provide the consumer with a
microbiologically cleaner and safer product.
The objectives of this study were to evaluate the effectiveness of Rinse and
ChillTM Technology as 1) a novel intervention method for reduction of
undesirable bacteria on beef carcasses and 2) a method to control or destroy
the growth of E. coli 0157:H7 in vacuum-packaged ground beef.
MATERIALS AND METHODS
Slaughter
Cattle were slaughtered humanely in each commercial facility. They were assigned
randomly to two groups, control or rinsed. For this study, animals were slaughtered
and rinsed on seven sampling events in Plant X; in Plant Y, animals were
slaughtered and rinsed on three sampling events. Cattle assigned to be rinsed
were bled by severing both jugular veins. Near completion of the bleeding, an
incision was made in the left carotid artery, and a catheter was inserted into the
artery for the rinsing process (MPSC, Inc., St. Paul, MN). The rinsing solution
consists of a mixture of dilute sugars and salts. Control groups were bled using the
traditional methods.
Carcass Sampling
Meat/Turkey Carcass Supply Kits from NASCO (Fort Atkinson, WI) were used to
collect the carcass sponge samples. Carcass sampling by the sponge method
followed the procedure described in the U.S. Meat and Poultry Inspection
Regulation. Ten milliliters of buffer was used to hydrate a sterile sponge. Another
15 ml was added to the sponge in the bag, to bring the total volume to 25 ml, after
swabbing the sample area with the sponge. Swabbing consisted of 10 horizontal
strokes and 10 vertical strokes in the template area of the brisket, flank and rump.
Carcass sponge samples were taken either 2 hours (Plant X) or 24 hours (Plant Y)
after carcasses were washed and placed in the coolers. The carcass sponge
samples were immediately refrigerated (<4ºC) prior to shipping overnight to the
laboratory in a Styrofoam insulated shipping container with freezer packs.
MATERIALS AND METHODS
Microbiological Analysis
Sponge samples were analyzed for aerobic plate count (APC) using 3MTM
PetrifilmTM Aerobic Count Plates (St. Paul, MN). Coliforms and generic E. coli
were analyzed using 3MTM PetrifilmTM E. coli Count Plates. Each sample was
stomached for 2 min. One millimeter of broth was removed from the sample bag
after stomaching and placed onto the respective PetrifilmTM plate. The samples
were plated in duplicate and the plates incubated at 37ºC for 48 h.
Vacuum-packaged Ground Beef Sampling
Ground beef was prepared from a 50/50 mixture of shoulder and chuck (w/w).
Rinsed and Control ground beef was inoculated with approximately 104 CFU/g
of E. coli 0157:H7. Twenty-five gram inoculated samples were vacuumpackaged and stored at refrigerated temperatures (4-10ºC) until microbiological
analysis. Triplicate samples were analyzed for the presence of APC and E. coli
O157:H7 at 1, 17, 31, 50, 70 and 92 days.
Statistical Analysis
All bacterial counts were converted to log10 CFU/ml for statistical analysis. The
statistical test used in this study was the student t-test (paired, two-tailed) and
the level of significance was considered p< 0.05. The calculations were
performed with Microsoft® Excel Version 2002, statistical functions (Microsoft
Corp., Redmond, Washington).
Analysis of APC and coliforms from 2 hour cooler
sponge samples over 7 sampling dates from Plant X
APC
N
Ave.
%
CFU/cm2 Reduction
Control
90
1224
R&C
90
731
Coliforms
N
Control
90
97
R&C
90
0.7
P value
(95% =
<0.05)
40.3%
Ave.
%
CFU/cm2 Reduction
0.039
Frequency
of
coliforms
P value
(95% =
< 0.05)
22/90
99.3
11/90
0.125
Analysis of APC and coliforms from 2 hour
cooler sponge samples over 7 sampling dates
from Plant X
3.5
Control
Rinsed
3
2.5
Log10 CFU/cm2
carcass sponge
2
1.5
1
0.5
0
-0.5
APC
Coliforms
Analysis of APC, coliforms and generic E. coli
from 24 hour cooler sponge samples over 3
sampling dates from Plant Y
APC
N
Ave.
CFU/cm2
%
Reduction
P value
(95% = <0.05)
Control
50
580
R&C
50
341
41.2%
0.009
N
Ave.
CFU/cm2
%
Reduction
Control
50
345
R&C
50
111
Generic
E. coli
N
Control
50
294
R&C
50
48
Coliforms
Ave.
CFU/cm2
Frequency of
coliforms
P value
(95% = < 0.05)
41/50
67.8
31/50
0.002
%
Reduction
Frequency of
generic
E. coli
P value
(95% = < 0.05)
31/50
83.7
16/50
0.0008
Analysis of APC, coliforms and generic E. coli
from 24 hour cooler sponge samples over 3
sampling dates from Plant Y
3
Control
Rinsed
2.5
Log10 CFU/cm2
carcass sponge
2
1.5
1
0.5
0
APC
Coliforms
Generic E. coli
Rinse & Chill Technology
On-going Protection
• Significant on-going protection in further processing of
carcasses, such as in ground beef
• Inoculated with E. coli 0157:H7;
• Vacuum packaged; 40F; 2 trials; triplicate
Ave.
(n=6)
Day
1
Log10
CFU/g
Control 4.65
Day 17 Day 31 Day 50
Day 92
Log10
CFU/g
Log10
CFU/g
Log10
CFU/g
Log10 CFU/g
Log10
CFU/g
3.81
3.06
2.68
2.77
2.27
3.39
2.05
1.81
2.07
0.82
0.007*
0.002*
0.0006*
0.021*
R&C
4.76
P value
0.141 0.005*
(95% - .05)
Day 70
Vacuum-packaged ground beef; 40 F
E. coli 0157:H7
5
C
R&C
4.5
4
3.5
3
Log10 CFU/g
E. Coli O157:H7
2.5
2
1.5
1
0.5
0
0
20
40
60
Day
80
100
Rinse & Chill Technology
Conclusions
Carcass swabs
w/Rinse &ChillTM
• Reduction in APC
– 40.3%
– 41.2%
• Reduction in coliforms
– 99.3%
– 67.8%
• Reduction in generic
E. coli
– 83.7%
Vacuum-packaged
Ground Beef
(shoulder/chuck - 50/50)
• Control – 2.38 log
reduction in E. coli
0157:H7 in 91 days
• Rinse & Chill – 3.94 log
reduction in E. coli
0157:H7 in 91 days
Research Conducted and
Supported by:
• University of Minnesota
– Department of Food Science and Nutrition, College of
Agriculture, Food and Environmental Sciences
• Joellen M. Feirtag, Ph.D.
– Department of Clinical and Population Sciences, College of
Veterinary Medicine
• Michael M. Pullen, DVM
• Agricultural Utilization Research Institute
– D.T. Bartholomew, B.J. Reuter, D. Timmerman
• MPSC, Inc.