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From: Food Quality & Safety magazine, October/November 2011

Multiply Your Meat and Poultry Attack

A multihurdle intervention strategy for USDA products improves pathogen control in an HACCP plan

by Charles J. Giambrone

In past articles I’ve written for Food Quality, I described in detail how intervention biocides can affect food safety from harvest through production.1-2

Intervention strategies have been on a rapid development track during the past decade, with a number of companies not only adopting the strategies in their processing plants but, in many cases, making them integral components of their hazard analysis and critical control points (HACCP) plans.

In my article “Be Ready to Beat Listeria (Food Quality April/May 2008),” I reviewed the U.S. Department of Agriculture Food Safety and Inspection Service’s (USDA FSIS) ready-to-eat (RTE) verification testing program alternatives.2-3 Intervention systems are a critical component in the decision-making process, especially utilizing alternatives one and two for an RTE FSIS operation. My objective is to highlight modalities that have become standard practice in USDA food safety programs (see Table 1).

The key regulatory document to review for many of the USDA FSIS applications for meat and poultry products is FSIS Directive 7120.1 Rev 7, which has the most comprehensive table of safe and suitable ingredients for intervention chemistries that are utilized as acidifiers—some of which overlap into the more important antimicrobial intervention chemistries.3

I have used PAA and acidified sodium chlorite solution as case study examples because I have worked closely with both as approved intervention chemistries for meat and poultry products. These two biocides provide solid efficacy, processing flexibility, and low environmental impact.

The past 10 years has seen an explosion of approvals using either basic organic acids such as acetic, citric, lactic, and a number of permutations of these blended with each other and with various fatty acids, or peracetic acid, also known as peroxyacetic acid (PAA). The latest trend has been to create the kind of synergistic biocidal activity used in FreshRinse, a wash created and patented by Chiquita for use on its Fresh Express produce.

Others include organic acid-salts-citrus extract blends and lauric aringinate (laurimide arginine ethyl ester, or LAE). Lytic phage and bacterial also have emerged as viable modalities. Bacteriophage cocktails have been developed by companies like Intralytix Corp., providing a truly microbial control approach for Listeria monocytogenes (LM) and E. coli 0157:H7 pathogen control, specifically in meat and poultry products. The phage blend is in 21 CFR 172.785, and the recently published FCN 1018 (all food contact notifications [FCNs] can be accessed via the U.S. Food and Drug Administration (FDA) website

Bacterial suspensions such as Carnobacterium maltaromaticum strain CB1 and Lactobacillus-Pediococcus blends are also used for pathogen control.

Biocides as Interventions

A number of biocides have been approved either in CFR, as an FCN, or both for direct application on meat and poultry products that are raw, comminuted, or cooked. Calcium and sodium hypochlorite, cetylpyridinium chloride, and chlorine gas all have CFR approval. Several specific biocides are worthy of note.

Summary of Biocide Intervention Approvals for Peracetic Acid & Acidified Chlorite. For Produce, Meat-Poultry and Seafood Applications.
click for large version
Table 1. Summary of Biocide Intervention Approvals for Peracetic Acid & Acidified Chlorite. For Produce, Meat-Poultry and Seafood Applications.

I have used PAA and acidified sodium chlorite solution (ACS) as case study examples because I have worked closely with both biocides as approved intervention chemistries for meat and poultry products. Based upon my application experiences, these two biocides as intervention chemistries provide solid efficacy, processing flexibility, and low environmental impact.

Electrolytically generated hypochlorous acid: Known as EO water, it’s an equipment-generating approach to create the biocidally effective hypochlorous acid without using chlorine gas cylinders. It can be utilized for red meat and poultry carcasses, processing waters, and poultry chiller waters (red chiller and makeup), as well as for bird reprocessing. The approved concentration ranges vary from 5 ppm for processing water to 20 ppm for bird reprocessing and 50 ppm for carcass sprays and poultry chiller waters.

Hypobromous acid: Utilized for a long time in processing water for can or bottle pasteurizers and coolers, this biocide has recent approvals. The first approved intervention application is for water and ice used in the processing of meat and poultry products. The approval is listed under FCN 944, issued in February 2010, and permits its use at 200 ppm for poultry product ice/water and 300 ppm for meat product ice/water. Meanwhile, FCN 1036 permits a higher usage rate for meat product process ice/water, up to 900 ppm available bromine.

Enviro Tech Corp. of Modesto, Calif., has developed a product that will be effective in a meat or poultry abattoir for full-carcass treatment, given hypobromous acid’s affinity for lipid surfaces like meat carcass skins. It is planned to be part of Enviro Tech’s multi-intervention approach to utilize hypobromous acid for carcass rinses and PAA for cuts and comminuted products.

Chlorine dioxide and ACS: While the precursors are the same in the many application modes available for produce as well as for meat and poultry products, there are two distinct CFR statutes for intervention chemistries:

Chlorine dioxide: The older “free” chlorine dioxide statute 21 CFR 173.300 requires the processor not to exceed 3 ppm residual-free chlorine dioxide as measured by the Standard Methods for the Examination of Water and Wastewater (4500-ClO2 E). The application and validation burden here is to accurately measure the level of free chlorine dioxide to comply with 173.300, whether it’s for USDA or FDA (produce or seafood) applications. There are numerous FCNs here, including 1052 (CDG Environmental), 668 (Drew-Ashland), and 644 (Diversey).

ACS: The more recent statute applied for by Alcide Corp. utilizes the total ACS level as the product to be titrated or measured for. ACS, like free chlorine dioxide, has applications for the produce-seafood FDA markets, as well as for the USDA FSIS meat and poultry markets. The ACS statute, CFR 173.325, permits use of a 500 ppm to 1200 ppm range.

Lower amounts are permitted by FSIS if the processor can validate the lower level’s efficacy in its operation. For example, Bio-Cide International was granted an FSIS approval in 2003 to utilize ACS in the 75 to 150 ppm range for cooked meat patties or loaves, with the caveat that the processor must maintain internal validation data. This refers to the older of two specific FCNs applicable for ACS; the older one, FCN 450 (November 2004), is for processed, comminuted, and formed red meats, including RTE products.

The more recent FCN applicable for ACS is FCN 739 (October 2007), which is for poultry products and includes whole carcass, parts, organ meat, and trim. Here, the pre-chiller or chiller water use range is 50 to 150 ppm. In all application instances, the free chlorine dioxide must not exceed 30 ppm in solution.

ACS Studies

ACS is utilized to control pathogens like Salmonella spp, E. coli 0157:H7, Listeria monocytogenes, and Campylobacter jejuni. Under 21 CFR 173.325, the ACS is activated using either food-grade phosphoric acid or citric acids. ACS concentration ranges vary depending upon the processing step. For beef carcass trimming and grinding, forming, and packaging, typical concentrations will range from 300 ppm for deboning to greater than 500 ppm for trimming and grinding.4

An internal Bio-Cide International study found some interesting results using ACS as an intervention for meat.5 On lean red meats, the use of Keeper Pro at 850 ppm reduced native microflora by 1.4 log10 cycles. On RTE sausage, a 2.4 log10 reduction of microflora was achieved after 30 days storage at 4 degrees C.

In a study conducted in December 2004 as a PhD dissertation at Louisiana State University, Richelle L. Beverly activated Keeper Pro with citric acid and exposed LM-contaminated cooked meat cubes to a range of activated ACS from 250 ppm to 1,000 ppm.6 ACS was effective in inhibiting the growth of LM contamination on refrigerated RTE meat products.

Examples of delivery systems for ACS intervention applications.
Figure 1. Examples of delivery systems for ACS intervention applications.

Beverly conducted refrigerated (4 degrees C/39 degrees F) 28-day shelf-life studies and demonstrated that two types of cooked roast beef that were treated with acidified Keeper Pro had log reductions for LM that became more pronounced as the shelf-life study progressed from day 0 to day 28, with four test concentrations of 250, 500, 750, and 1,000 ppm ACS. For example, day 7 showed results that ranged from 3 log10 reductions for 250 ppm ACS to 4.7 log10 reduction for 1,000 ppm. LM control had 7.25 log10. Day 14 consistently had roughly 4 log10 reductions for 250 up to 1,000 ppm ACS. LM control had 9.5 log10.

Poultry products have also been successfully treated using ACS in Ecolab’s Sanova program and in Bio-Cide International’s Keeper and Keeper Pro programs. In a chicken carcass rinsate study presented at the International Poultry Expo 2006 in Atlanta, researchers sprayed 1,000 ppm ACS for 30 seconds on carcasses contaminated with E. coli 0157:H7. Results showed ACS-treated carcasses achieved a 2 log cycle reduction for total aerobes and a 1.5 log10 reduction for E. coli 0157:H7.7

Peracetic or Peroxyacetic Acid

Under 21 CFR 173.370, approved in November 2000, Ecolab Corp. obtained approval for PAA from the federal government as an intervention biocide for meat and poultry carcasses, parts, and organs, with a PAA maximum concentration up to 220 ppm. For meat, the hydrogen peroxide cannot exceed 75 ppm; for poultry, the upper peroxide limit is 110 ppm.

Besides the CFR approval, numerous suppliers have received FCNs for specific products. All these products typically utilize a blend of 15% PAA, 10% peroxide. All peroxyacetic acid is an equilibrium mixture of peroxyacetic, acetic acid, and hydrogen peroxide; PAA is manufactured from precise blending, reaction control, and processing to attain the precise equilibrium derived from the chemical reaction between glacial acetic acid and concentrated hydrogen peroxide.

FMC Corp.’s FCN 323 obtained approvals for process waters for red meat and poultry carcasses, parts, and trim for up to 230 ppm PAA but with peroxide levels up to 165 ppm. Another FCN, No. 880 by FMC, obtained permission to use up to 2,000 ppm PAA for poultry parts, organs, and carcasses in cold (less than 40 degrees F) process water, as well as for scald water applications. Brainard Chemical recently received FCN 993 for meat and poultry applications similar to FMC’s but up to the 220 ppm PAA level.

Enviro Tech Corp. has obtained several specific FCNs for PAA applications as interventions for seafood, meat, and poultry. Starting in 2007, FCN 699 was approved for up to 190 ppm PAA for fish and seafood ice and wash water.

The key provisions for meat and poultry, though, included FCN 887 (June 2009) for processing water or ice for carcass, parts, trim, and organs for meat and poultry up to 220 ppm PAA and 85 ppm peroxide and FCN 908, which gave Enviro Tech approvals for its PAA to be used as an antimicrobial additive in process waters/ice for processed or pre-formed meat and poultry products.

PAA Studies

Through the years, a number of fascinating intervention studies involving the use of PAA with meat and poultry have been conducted.

A 2010 Oklahoma State intervention study used OSU’s biosafety facility to compare a variety of intervention modalities to reduce E. coli 0157:H7.8 Sirloin patties with 8 log10 cycle challenge of E. coli 0157:H7 antibiotic-resistant strains for a 30-minute attachment period were treated with a variety of intervention chemistries using a Ross Tenderizer spray unit dosing a variety of intervention chemistries for 18 seconds at 1.5 gallons/minute. For example, PAA with lauric arginate achieved nearly a 2 log10, or 99%, reduction. After 14 days storage, the blend of PAA with lauric arginate had actual synergistic biocidal activity, achieving more than a 2.7 log10 reduction.

Enviro Tech Corp. conducted an internal study in 2009 using PAA to control field strains of E. coli 0157:H7 in a series of well-designed studies comparing PAA with hypobromous acid with an oxidant biocide, DBDMH, a dried powder form of hypobromite from Albemarle Corp.9

Raw London broil beef strips or pork strips were inoculated with the E. coli 0157:H7 strain, and the three test intervention biocides were applied using either 10 or 70 psi pressure spray applied in a spray cabinet at 30 seconds with a 0.6 gpm test solution per nozzle.

Using a very short spray contact period of 30 seconds, both the PAA and the liquid hypobromous biocide interventions showed promise, with PAA performing the best; PAA achieved 1 log reduction and a 2 log10 reduction on beef and pork models.

A pork abattoir shelf-life study was conducted using 15% PAA. In a study for a former Rochester Midland Corp. customer in Southern Illinois, we utilized PAA to control microbial flora at a pork processing plant that was spraying a belt with 180 ppm available PAA to control microbial flora on tenderloin pork cuts, following standard practice. The study implemented a dip tank for the same level of PAA for 30 seconds.10

Total aerobic and coliform counts were measured on the actual tenderloin cuts, after the 180 ppm was applied on days 0, 7, 9, 14, 21, 24, and beyond. Some aerobic plate count results concluded that having a dip tank with the same concentration of 180 ppm with a 30-second dwell time outperformed the spray belt application.

Examples of delivery systems for ACS intervention applications.
Figure 2. Examples of delivery systems for PAA intervention applications.

Your Program

Most of these studies, as well as others not mentioned here, clearly demonstrated that even with the most effective modalities using synergistic biocidal chemistries or proper dip systems, the goal of attaining more than 5 log10 cycle reductions of pathogens is unachievable.

This is the rationale for using several different organic acid/microbial control/biocide-based intervention strategies in your pathogen reduction and control programs as part of your HACCP. By hitting your process from, say, the scalder in a poultry plant to the carcass washer in a beef or pork abattoir, followed by a different modality in the process water for poultry or on the carcass sides/quarters through the cuts or parts in beef/poultry, you can attack potential pathogens and spoilage microbes several times. Many beef, pork, and poultry processors are embracing this multi-intervention approach, using two or three systems. This is why not only beef cuts, but also comminuted and bagged products, are treated with an intervention measure and why some processors are treating poultry carcasses post-chiller as well.

This concept is consistent with the microbial ecological controls that work in nature to control microbial pathogen populations. These foodborne pathogens must overcome more than one obstacle in real field conditions, and you need to do the same in your processing plant. This way we all have a better chance at controlling the variety of foodborne pathogens that affect raw and RTE products.

Charles J. Giambrone, MS, is global technology and regulatory manager for the food safety division of Rochester Midland Corp.


  1. Giambrone C. Pathogen can’t hide from biocides. Food Quality. February/March 2008. Available at: details/article/814573/Pathogen_Cant_Hide_From_Biocides.html. Accessed July 7, 2011.
  2. Giambrone C. Be ready to beat Listeria. Food Quality. April/May 2008. Available at: Accessed July 8, 2011.
  3. U.S. Department of Agriculture. Food Safety Inspection Service. FSIS Directive 7120.1Revision 7. Safe and suitable ingredients used in the production of meat, poultry, and egg products. Available at:
    +6&output=xml_no_dtd&client=FSIS&access=p&ie=UTF-8&oe=UTF-8&num=10&site=FSIS&proxystylesheet=FSIS. Accessed July 8, 2011.
  4. Bio-Cide International, Inc. Keeper red meat product bulletin. Available at: Accessed July 5, 2011.
  5. Bio-Cide International, Inc. Bio-Gram Newsletter, 2011. Available at: Accessed July 5, 2011.
  6. Beverly RL. Acidified sodium chlorite treatment for the inhibition of Listeria monocytogenes on the surface of ready-to-eat roast beef. In: The Control, Survival, and Growth of Listeria Monocytogenes on Food Products [dissertation]. Baton Rouge, La.: Louisiana State University; 2004:58-87.
  7. Doan T, Cochran M, Khanna N. Use of acidified chlorite for sanitation of poultry carcasses. Presented at Poultry Science Association on Jan. 23, 2006.
  8. Spillner W, Muriana P. Integral Antimicrobial Solution Application Systems on Ross Blade Tenderizers. OSU Intervention Study Topline, Phase 1, Oklahoma State University and Ross Corp. Presented at North American Meat Processors Association October 2010.
  9. Rodrigues T, Mesrobian C, Harvey M, et al. Efficacy of several antimicrobial processing aids sprayed on meat and pork products against E. coli 0157:H7. Enviro Tech Chemical Services Inc. Sept. 25, 2009. Available at: Accessed July 10, 2011.
  10. Peracetic acid and pork shelf life at pork abattoir. FMC Corp & RMC Corp joint study, November 2005 to January 2006.



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