Download E. coli

Interventions to improve
microbial safety
– Compounds, Ingredients, Processes
1. Carcass washing - remove, reduce beginning
numbers
– remove bacteria before they attach to meat surfaces
– a. hot water
– 95oC wash pre-chill
– ~90% of beef plants currently use hot water
– reduce E. coli O157:H7 and Salmonella
– will reduce spoilage organisms also
but…most are picked up in post-chill processing
-recently approved phage for E. coli
b. organic acids
–
–
–
–
approved since 1992
lactic or acetic acid most common
1- 2% solution
especially effective if used after hot water spray - cells
are susceptible
– complex mixtures also developed
peroxyacetic acid, hydrogen peroxide, octanoic acid,
acetic acid = “Inspexx” (brand name); Inspexx 100 =
poultry; Inspexx 200 = red meat (USDA approved)
– good for Salmonella, Staphylococcus sp, Listeria
monocytogenes
– however, E. coli is acid resistant
c. steam
– steam pasteurization
– 6.5 - 8 seconds of steam under pressure
– raises carcass surface temperature to ~185oF
– followed immediately by cold water spray to prevent surface cooking
– kills 95 - 99% of bacteria
– steam vacuuming also developed to clean contaminated
areas on carcasses - alternative to knife trimming
– effective for Salmonella sp, Listeria sp and E. coli
O157:H7
d. tri-sodium phosphate
– approved in 1994, first for poultry
– primary effect seems to be to prevent microbial cell
attachment
– especially effective if combined with organic acid
sprays
e. acidified sodium chlorite
– citric acid plus sodium chlorite
– surface spray treatment
– primarily used for poultry but approved for red meat
and being adopted
– is effective against virtually all microorganisms
including E. coli O157:H7 which is acid resistant
2. Ingredients
a. sodium/potassium lactate
– permitted at 3% (4.8% of commercial solution
which is 60% lactate)
– also seems to improve water retention, flavor
and color
Inhibition of Listeria in an Uncured Chicken Roll
(stored at 40o F)
9
8
0% NaL
2% NaL
4% NaL
7
Log
(CFU/gram) 6
5
4
3
2
8
15 22 29 36 45 52 60
time (days)
Inhibition of Listeria in an Cured Frankfurter (stored at
40o F)
8
7
0% NaL
2% NaL
4% NaL
6
Log
(CFU/gram) 5
4
3
2
1
0
8
15 22 29 36 45 56
time (days)
b. sodium diacetate
– permitted at 0.25%: most often used with lactate
– diacetate = 1:1 sodium acetate : acetic acid
c. activated lactoferrin
– discovered in 1939
– approved Jan, 2002 by USDA for meat applications
and as GRAS substance by FDA in Oct, 2001 for
other foods
– natural compound from milk found in blood, saliva,
tears
– effective against ~ 30 pathogens including
Salmonella, E. coli O157:H7
c. activated lactoferrin (continued)
– binds iron very, very tightly which may be how it
inhibits bacteria --- would also function as
antioxidant
– lactoferrin is a antimicrobial peptide
– glycoprotein of ~ 700 amino acids
– recent research has isolated a peptide called PR-39 from
pork white blood cells that is antimicrobial
– may be another natural antimicrobial
d. cetylpyridinium chloride
– quarternary ammonium compound
– lethal to Salmonella, E. coli and Listeria
– currently allowed for exterior package surfaces,
plant surface sanitizer and to treat chilling solutions
used to cool cooked products
– not yet approved by FDA or USDA for direct food
use but approval is expected because
– has been used for over 40 years in products like
mouthwash
e. dried plum products “prunes”
– 3% plum extract inhibits E. coli O157:H7,
Salmonella, Listeria and Staphylococcus sp
– also helps retain moisture, and has antioxidant
activity
– does not change flavor
3. Processing treatments
a. Post-packaging pasteurization with heat
– 80 - 90oC for ~ 1 minute will greatly reduce
pathogens and spoilage types
– most significant for Listeria due to post - cooking
surface contamination
– effects are very dependent on package arrangement
–
single packaged
franks
Vs
single rows
Vs
double rows
– need to be careful about product effects especially
increased purge
b. irradiation
– approved for poultry in 1992 and red meat in 2000
– clearly effective against all microorganisms
– gamma (radioactive source), electron beam (limited
penetration), and X-ray sources
– minimal product change
i.e. product retains “raw” characteristics
– must be labeled as irradiated
– not yet approved for multicomponent (processed meat
products)
c. high pressure processing
– use of ~87,000 psi to kill bacteria by disrupting cell
functions (enzymes, membranes)
– advantageous for both pathogen control and shelf life (spoilage)
– does not alter product --- retains “raw” characteristics
– Hormel currently utilizes high pressure for processed ham
products, and “natural” products
– requires no special regulations or labeling
– typically a batch process done post packaging
4. Bacteriophages
– Highly specific for different bacterial strains
– Approved by FDA (2006) for use in foods including meat
to reduce L. monocytogenes (Intralytix LMP-102™)
– Also received FDA approval (~2010) of a phage product
(ECP-100™ ) for E. coli 0157:H7
– Recently, FDA GRAS approval for Salmonella
(Salmofresh) (www.intralytix.com) – targeting poultry
– Currently developing phage for Clostridium perfringens