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 –95 o C 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 – seconds of steam under pressure –raises carcass surface temperature to ~185 o F –followed immediately by cold water spray to prevent surface cooking –kills % 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 40 o F)

Inhibition of Listeria in an Cured Frankfurter (stored at 40 o F)

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 – o C 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 single rows double rows –need to be careful about product effects especially increased purge Vs

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) ( – targeting poultrywww.intralytix.com –Currently developing phage for Clostridium perfringens