← FAT Research Library

✍️ Dirk Adams with the assistance of AI

⌛ 24 min read · Sources: 59 (EFSA, FAO/WHO, USDA FSIS, NZ FSA, CDC, and peer-reviewed literature)

BROILER CHICKEN INDUSTRY RESEARCH SERIES

The Chemistry That Isn’t on the Label: Antimicrobial Washes in U.S. Broiler Processing

Nearly every conventionally processed chicken sold in the United States has been treated with an antimicrobial chemical before it reaches the package. No federal label discloses which chemical, at what concentration, or by what method. This paper examines what the peer-reviewed literature and official risk assessments actually establish about those treatments — and finds that the strongest concern is not the one consumers have been told to worry about.

1. The Question Behind “Chlorinated Chicken”

Few phrases in food-trade politics have travelled further on less examination than “chlorinated chicken.” It has served as shorthand in British and European trade debates for a decade, usually as a stand-in for a broader anxiety about American food standards. It is also, as a description of current U.S. practice, substantially out of date.

Chlorine is still used in U.S. poultry plants, but it is no longer the principal antimicrobial in carcass chilling. Peracetic acid — more precisely peroxyacetic acid, or PAA — has largely displaced it, and cetylpyridinium chloride, acidified sodium chlorite and trisodium phosphate all appear in various applications. Any serious examination has to address the chemicals actually in use rather than the one in the headline.

This paper asks four questions in order, and answers them from peer-reviewed literature and official scientific assessments only. No advocacy-group, trade-association or trade-press source is used as evidence anywhere in this document.

• What is actually applied to a U.S. broiler carcass, and at what concentration?
• Is there evidence that eating the resulting product is harmful?
• Does the treatment do what it is supposed to do?
• What, if any, of this reaches the consumer as disclosed information?

The fourth question is the one Farm Animal Transparency exists to ask, and it turns out to be the one where the evidentiary picture is clearest. The answer is: none of it.

This paper is a companion to Comparison of Water-Chilled vs. Air-Chilled Chicken in U.S. Poultry Production in this series, which noted that immersion chiller water is “often treated with antimicrobial additives such as chlorine or organic acids” but did not examine those additives. This paper examines them.

2. What Is Actually Applied to a U.S. Broiler Carcass

U.S. antimicrobial use in meat and poultry operates on a “prohibited unless listed” principle. Under 9 C.F.R. § 424.21(b)(2):

“No food ingredients or sources of radiation may be used in the preparation of any meat or poultry product, for any purpose, unless the use is listed or approved in 21 CFR chapter I as a direct food additive … a secondary direct food additive (21 CFR part 173) … a prior-sanctioned substance (part 181), a Generally Recognized As Safe (GRAS) substance (parts 182 or 184), or by a regulation in this chapter.”

9 C.F.R. § 424.21(b)(2)

Approval runs through a combination of FDA additive regulations, GRAS determinations, Food Contact Notifications, and FSIS “safe and suitable” listings maintained in Directive 7120.1. The concentrations below are the ones we were able to verify against primary regulatory text.

Substance	Application	Permitted concentration	Authority
Acidified sodium chlorite	Spray or dip	500–1,200 ppm sodium chlorite, pH 2.3–2.9	21 C.F.R. § 173.325(b)(2)
Acidified sodium chlorite	Prechiller / chiller	50–150 ppm sodium chlorite, pH 2.8–3.2	21 C.F.R. § 173.325(b)(3)
Peroxyacids	Carcasses, parts, organs	220 ppm as peroxyacetic acid; H₂O₂ 110 ppm; HEDP 13 ppm	21 C.F.R. § 173.370(b)(2)
Peroxyacetic acid (FCN 2274)	Process water, chiller water, immersion baths, scald water	2,000 ppm PAA; H₂O₂ 1,474 ppm; HEDP 100 ppm	FSIS Directive 7120.1 Rev. 59
Peroxyacetic acid (FCN 2266)	Wash, spray, dip, rinse, chiller water, scald water	2,000 ppm PAA; H₂O₂ 1,333 ppm; HEDP 133 ppm	FSIS Directive 7120.1 Rev. 59
Sodium metasilicate	Spray or dip, whole or cut carcasses	2–4%	FSIS Directive 7120.1 Rev. 59

A gap in the public record

FSIS Directive 7120.1 Revision 59 states in terms that it “no longer provides the complete listing of approved substances” and “only provides a list of the latest changes.” The complete list resides in a separate table we were unable to retrieve. As a result, this paper contains no verified FSIS concentration limit for chlorine or hypochlorite, cetylpyridinium chloride, or trisodium phosphate — three of the substances most central to the subject. That the authoritative list of what may legally be applied to American chicken is not readily retrievable is worth stating plainly.

3. The Disclosure Gap

Here is the finding that matters most for a consumer standing in a grocery aisle: none of the treatments described in Table 1 appears on the label of the product.

Antimicrobial washes are regulated as processing aids. The regulatory logic is that a substance applied during processing which does not have a technical effect in the finished food need not be declared in the ingredient statement. Whether that logic is sound is a legitimate question — the treatments demonstrably extend shelf life, which is a technical effect in the finished food — but as a description of current practice it is accurate. A package of U.S. chicken carries no indication of:

• whether any antimicrobial was applied at all;
• which substance was used — chlorine, peracetic acid, cetylpyridinium chloride, acidified sodium chlorite or another;
• the concentration applied, which as Table 1 shows can range across more than an order of magnitude for the same substance;
• the application method — spray, dip, or immersion in shared chiller water — despite EFSA’s finding that spraying produces materially lower residue exposure than immersion;
• whether the bird was immersion-chilled in shared, chemically treated water at all.

The practical consequence is that two packages of chicken sitting side by side, at the same price, from plants operating at opposite ends of the permitted concentration range and using different chemistries entirely, are indistinguishable to the buyer. There is no claim to verify, because there is no claim.

This is a different kind of transparency problem from the ones FAT more commonly documents. With “natural,” “family farm,” or “humanely raised,” the issue is a claim that is made but weakly defined or unverified. Here there is no claim at all — the information simply does not enter the labeling system. A consumer who wanted to avoid chlorine-washed chicken, or who wanted to seek out a plant using a lower-concentration intervention, has no lawful mechanism for doing so through the label.

Two partial exceptions are worth noting. Air-chilled chicken is sometimes voluntarily labeled as such, and because air chilling does not involve immersion in a shared chemical bath, that claim carries indirect information about processing chemistry. And retained-water declarations, required where immersion chilling causes weight gain, indirectly signal immersion processing. Neither is a disclosure of antimicrobial treatment, and neither is required.

4. Is It Harmful to Eat? What the Risk Assessments Found

This is the question most often asked and the one where the evidence most clearly does not support the popular concern. We report it that way because a transparency project that only reports findings favorable to its priors is not a transparency project.

The foundational European assessment

EFSA’s Panel on Food Additives, Flavourings, Processing Aids and Materials in Contact with Food assessed four of these substances in an opinion adopted in December 2005. Its overall conclusion was unambiguous:

“Treatment with trisodium phosphate, acidified sodium chlorite, chlorine dioxide, or peroxyacid solutions, under the described conditions of use, would be of no safety concern.”

EFSA AFC Panel, The EFSA Journal (2005) 297

The modelled dietary exposures behind that conclusion, for a 60 kg adult, are given in Table 2. They are not marginal.

Residue	Mean exposure	99th percentile	Reference value	Margin
Trisodium phosphate	1.21 mg/kg bw/d	2.80	MTDI 70 mg/kg bw	≤4% of MTDI
ASC → chlorite	0.04 µg/kg bw/d	0.09	TDI 0.03 mg/kg bw	300–1,000× below
ASC → chlorate	0.05 µg/kg bw/d	0.11	TDI 0.03 mg/kg bw	300–1,000× below
ClO₂ → chlorite	0.33 µg/kg bw/d	0.76	TDI 0.03 mg/kg bw	40–1,000× below
Peroxyacids + H₂O₂	0.6 µg/kg bw/d	1.5	PAA LOAEL 0.13 mg/kg bw/d	large margin

On semicarbazide — a breakdown compound that generated early concern — the Panel reported that it “was not detected (limit of detection of 1 microgram/kg) in laboratory tests on poultry carcasses after treatment by immersion with acidified sodium chlorite,” in tests run at ten times the normal use concentration with overnight contact. It added that “the initial health concerns about semicarbazide are no longer relevant … new data showed that semicarbazide is not genotoxic in vivo.”

Where the assessing bodies flagged their own uncertainty

Three specific limitations are named by the agencies themselves and deserve to be reported alongside the reassuring headline.

Trihalomethane data on food, as opposed to in water, is weak. The joint FAO/WHO expert meeting stated:

“The identified residues of chlorine-containing disinfectants and disinfection by-products did not raise health concerns based on estimated dietary exposures. However, the evidence for health concerns associated with hypochlorite use in poultry, fish and shellfish was weak, owing to a lack of qualitative and quantitative information on the formation and presence of trihalomethanes … on the food. It was noted that although generally conservative estimates were used, there was a high degree of uncertainty in the dietary exposure assessments, as data on by-products were available primarily for drinking-water, and these data would have limited applicability to food.”

FAO/WHO expert meeting report, 2009

EFSA named a data gap on chlorine dioxide that it did not consider closed: “Further data might be needed to confirm that chlorinated compounds are not generated to a significant extent.”

Brominated by-products in chicken have never been studied. A New Zealand government scientific review noted that for bromodichloromethane, dibromochloromethane and bromoform, “studies of absorption of these compounds have not been reported in the literature.” These compounds are more fat-soluble than chloroform and would preferentially concentrate in fat.

The same New Zealand review provides the most detailed public dataset on chloroform in treated chicken tissue. Under the harshest condition tested — 50 mg/L chlorine, 5 minutes, 15–16 °C — mean chloroform reached 177 µg/kg in muscle and 447 µg/kg in fat. Modelled against that worst case, exposure was 0.3 µg/kg bw/day for adults and 0.5 for children aged 5–15, against a tolerable daily intake of 10–15 µg/kg bw/day. Temperature mattered considerably more than contact time, and cooking substantially reduced residues.

The finding that does not fit the reassuring narrative

One conclusion in the FAO/WHO report concerns effectiveness rather than safety, and cuts sharply against the practice. The meeting recorded “evidence that no pathogen reduction is achieved by application of sodium hypochlorite on poultry carcasses and red meats,” while acidified sodium chlorite and chlorine dioxide did reduce pathogens.

An intervention that produces no measurable pathogen reduction, but which is nonetheless applied and nonetheless undisclosed, raises a different question than a toxicological one.

5. Does It Work? Measured Efficacy

The efficacy literature is more equivocal than industry summaries suggest, and the direction of the error is consistent: older studies reported larger reductions than newer ones.

Head-to-head comparisons

Zhang and colleagues (2018) tested five antimicrobials in a post-chill decontamination tank on inoculated broiler parts. The ranking is instructive:

Treatment	Salmonella	Campylobacter
Cetylpyridinium chloride (0.35% / 0.60%)	2.5–3.5 log	4–5 log
Peracetic acid (0.07% / 0.1%)	~1.5 log	~1.5 log
Chlorine (0.003%)	<1 log	<1 log
Acidified sodium chlorite (0.07%)	<1 log	<1 log

Chlorine and acidified sodium chlorite were described by the authors as “the least effective antimicrobials.” A peer-reviewed review by Thames and Theradiyil Sukumaran (2020) reports findings in the same direction and adds a striking one: 50 ppm chlorine applied to drumettes during chilling “had the same effect as distilled water,” with 2–3 log CFU/mm of both pathogens recovered under both conditions. The same review records that in a chiller study, 30 ppm chlorine reduced positive isolates by 56.8% for Salmonella and 12.8% for Campylobacter, against 91.8% and 43.4% for an 85 ppm peracetic acid mixture.

Two mechanistic points explain much of this. Chlorine’s effectiveness “is greatly reduced by a high pH (>7) and large quantities of organic content” — and a poultry chiller is, by definition, an environment saturated with organic content. Free chlorine added to such a system is consumed almost immediately. Research on chiller cross-contamination found that while fewer uninoculated carcasses became positive at 50 ppm than at 0 ppm, cross-contamination was not eliminated, and chlorine concentration “decreased rapidly because of organic matter.”

What the pooled evidence shows

A 2024 systematic review and meta-analysis in Poultry Science covering 2000–2021 found peroxyacetic acid produced the largest reduction against Salmonella regardless of chilling time, and the largest against Campylobacter during primary chilling. A 2022 meta-analysis in Food Microbiology covering Campylobacter decontamination during primary processing found a pooled reduction of 0.6 log₁₀ CFU per carcass and a 57.2% decrease in relative risk of prevalence — with very high heterogeneity between studies and detectable publication bias in the prevalence trials.

A pooled reduction of 0.6 log means roughly a 75% reduction in bacterial load. That is a real effect. It is also far from sterilization, and it is the average across all interventions studied, not the performance of chlorine specifically.

The regulator’s own caution

EFSA’s Panel on Biological Hazards, assessing peracetic acid on poultry in 2014, found the evidence base thinner than the industry literature implies:

“A relevant reduction of PAA treatment on E. coli and coliforms was demonstrated by dipping warm carcasses, but few data were available for pathogens (Salmonella and Campylobacter).”

EFSA BIOHAZ Panel, EFSA Journal 2014;12(3):3599

For chiller-bath application specifically, EFSA found “little data on pathogen reduction.” Where reductions in chilled carcasses were evident, they appeared “only in low- or medium-strength-of-evidence studies.” Six years earlier, assessing the four substances proposed for EU authorization, the same Panel had been “unable to say if these substances effectively killed or reduced bacteria on poultry” for want of sufficient data.

6. The Measurement Problem

This section contains the strongest evidence in this paper. It is also the least discussed publicly, and it is squarely a transparency issue rather than a toxicological one.

The sanitizer keeps working inside the sample container

Poultry carcasses are tested for Salmonella and Campylobacter by rinsing the bird in a buffered solution and culturing the rinse. If antimicrobial chemical is carried over from the carcass into that rinse, it continues killing bacteria in the sample bottle — and the resulting count reflects the chemistry of the laboratory container as much as the condition of the bird.

Gamble and colleagues (2016), working at USDA’s Agricultural Research Service, quantified this. Five sanitizers were diluted into buffered peptone water at realistic drip-time equivalents and spiked with Salmonella at 10⁵ CFU/mL. At the 0- and 1-minute drip equivalents, three of the five sanitizers permitted no Salmonella recovery at all. The authors concluded that the standard recovery protocol “may potentially result in a false negative due to sanitizer carry-over into the carcass rinsate.”

What happened when USDA fixed the method

In July 2016, FSIS replaced buffered peptone water with neutralizing buffered peptone water for poultry verification sampling. Analysts in the agency’s own Risk Assessment and Analytics Staff then measured what changed. Williams and colleagues (2018) found that after the switch, apparent Salmonella prevalence in carcass samples rose from approximately 2% to approximately 6% — roughly a tripling. The paper frames this as validating the concern that antimicrobial carryover had been producing false negatives.

Alive but uncountable

A related and more fundamental problem is that bacteria can survive these treatments in a state where they no longer grow on standard culture media. This is the viable-but-nonculturable, or VBNC, state.

Purevdorj-Gage and colleagues (2018) compared microscopic viability counts to plate counts on poultry after treatment, and found that lactic acid and peracetic acid “generated a greater number of microscopic counts compared with the corresponding plate counts with differences being around half a log.”

Highmore and colleagues (2018), working in mBio, established that the surviving cells remain dangerous. Total viable Salmonella Thompson populations became nonculturable at 100 ppm chlorine “while enumeration by direct viable counting found that chlorine caused a <1-log reduction in viability" — and those nonculturable cells remained infectious in a live model organism. This study used spinach, not poultry, and we flag that limitation rather than let the mechanism be assumed to transfer.

The poultry-specific demonstration arrived in 2026. Navarre, Quintana-Pérez and Kovac, publishing in Food Control, inoculated chicken breasts with Campylobacter and treated them with 500 ppm peracetic acid for 10 seconds by spray or immersion, then measured culturable cells by plating and viable cells by viability qPCR. Their result:

“Immediately after treatment, immersion insignificantly reduced the viable Campylobacter population by 0.3 ± 0.2 log₁₀ (p = 0.99) but significantly reduced the culturable population by 0.8 ± 0.1 log₁₀ (p < 0.001) … Overall, the culture-based plating method overestimated the antimicrobial effect of PAA by up to 1.0 ± 0.3 log₁₀ due to VBNC."

Navarre, Quintana-Pérez & Kovac, Food Control 180:111652 (2026)

Read carefully, that is a considerable finding. At 500 ppm — well within the permitted range — the treatment did not significantly reduce the number of living Campylobacter on the meat by either application method. What it significantly reduced was their ability to grow on a plate. And because typical reported reductions across this literature are 1–2 log, an overstatement of up to 1.0 log is not a rounding error.

Supporting this, Weerasooriya and colleagues (2022) fed chlorine-exposed Campylobacter jejuni to mice and reported that “chlorine exposure was unable to reduce intestinal colonization by C. jejuni,” while acidified sodium chlorite significantly reduced colonization and tissue translocation. Injured cells retained their capacity to infect.

What we could not establish

A frequently made claim is that antimicrobial washes suppress the spoilage organisms that would otherwise warn a consumer the meat is going off, while pathogens survive — the “smells fine but isn’t” argument. We found no study that tests this directly, and we do not assert it. It is a plausible inference from the shelf-life extension documented for peracetic acid combined with the VBNC findings above, but plausibility is not evidence, and nobody appears to have tested the proposition head-on.

7. Antimicrobial Resistance

The concern that biocide exposure selects for antibiotic resistance is real, documented, and more modest than often claimed. The honest summary is that it depends heavily on which chemical.

Wu-Chen and colleagues (2023) exposed 27 Salmonella Typhimurium strains to escalating concentrations of five food-grade disinfectants and tested the evolved strains against 14 clinically important antibiotics. 22 of 135 evolved strains showed increased antibiotic resistance; 9 of 135 showed decreased resistance. Benzalkonium chloride — a quaternary ammonium compound — induced the most cross-resistance; hydrogen peroxide induced the most loss of resistance.

Xiao and colleagues (2022) surveyed 172 Salmonella isolates from Chinese poultry farms, slaughterhouses and retail markets. Chlorine tolerance at MIC > 256 mg/L was present in 93.6% of isolates, with significant positive correlations to ceftiofur, tetracycline, ciprofloxacin and florfenicol resistance. The most frequently detected resistance gene was qacEΔ1, at 83.1%. That gene is a class-1 integron marker, so genetic co-location is at least as plausible an explanation as biocide-driven selection — an important interpretive caveat.

Alonso-Hernando and colleagues (2009) tested poultry decontaminants specifically and found MIC increases of at most 1.88 to 2.71-fold. Their own conclusion was deflationary: the responses “are of minor concern.”

The FAO’s expert meeting supplies both the balanced position and the mechanistic reason it differs by chemical class:

“While such laboratory studies point to the possibility of cross-resistance between biocides and antimicrobials … laboratory studies do not always adequately mimic external conditions that occur under routine use. Studies investigating the development and occurrence of cross-resistance in situ are few and results are inconclusive.”

FAO, Biocides and Antimicrobial Resistance, 2018

The same report notes that agents with a “narrow mode of action” are more prone to driving resistance, whereas “resistance to biocides acting on multiple bacterial metabolic pathways would require the simultaneous acquisition of resistance to these different modes of intervention … a process that is less likely to occur.” Chlorine and peracetic acid are multi-target oxidizers. Quaternary ammonium compounds are not.

8. The Regulatory Divide

There is no European ban on chlorine

A persistent misconception deserves correcting. No EU law names chlorine. The operative provision is Article 3(2) of Regulation (EC) No 853/2004:

“Food business operators shall not use any substance other than potable water — or, when Regulation (EC) No 852/2004 or this Regulation permits its use, clean water — to remove surface contamination from products of animal origin, unless use of the substance has been approved in accordance with the procedure referred to in Article 12(2).”

Regulation (EC) No 853/2004, Article 3(2)

Chlorine, peracetic acid, chlorine dioxide, acidified sodium chlorite, cetylpyridinium chloride and trisodium phosphate are unlawful in the EU for this purpose because no one has obtained authorization for them — not because any is specifically prohibited. Structurally, this is the same “prohibited unless listed” logic as 9 C.F.R. § 424.21. The difference is the approval machinery.

The 2008 rejection

A Commission proposal to authorize four substances for poultry was formally rejected by the Council in Decision 2009/121/EC: “The proposal … as regards the use of antimicrobial substances to remove surface contamination from poultry carcasses is rejected.”

The grounds are worth noting, because they were not dietary toxicity — EFSA had already advised there was none. Recital (4) cited risk “to the aquatic environment, the health of staff working in waste water systems and the operation and performance of sewerage systems and/or waste water treatment plants.” Recital (9) stated “it cannot be excluded that the approval of theses [sic] substances may lead to an increased antimicrobial resistance in humans.” Recital (13) expressly invoked the precautionary principle.

The pathway does work — and contains a lesson

Two substances have been authorized under the same provision, which disposes of any claim that the EU regime bans decontamination chemistry outright. Commission Regulation (EU) No 101/2013 authorizes lactic acid on bovine carcasses; Commission Regulation (EU) 2015/1474 authorizes recycled hot water.

One provision of the lactic acid regulation bears directly on this paper’s subject. Its Annex requires that sampling for compliance with microbiological criteria be carried out before the decontaminant is applied. The treatment cannot be used to convert a failing process into a passing sample. Given the measurement findings in Section 6, that is a notably well-designed rule.

The current U.S. position, and a reversal

FSIS Directive 10,250.2 states plainly: “FSIS does not consider raw poultry containing Salmonella to be adulterated … Establishments are not required to segregate or hold product when the establishment exceeds a performance standard.” The same directive notes FSIS “does not assess whether establishments meet the [Campylobacter] performance standards,” a position in place since August 2018. There is currently no operative U.S. Campylobacter standard at all, while the EU has had a broiler-carcass Campylobacter process hygiene criterion since January 2018.

In August 2024 FSIS proposed a framework that would have declared certain Salmonella levels and serotypes adulterants in raw poultry. That proposal was withdrawn on 25 April 2025 (90 FR 17344), citing comments on the agency’s legal authority, the supporting science, and burden on small producers. A public meeting followed in January 2026; no replacement rule has been proposed. The 2016-era performance standards remain the operative regime.

9. Upstream Control vs. End-of-Line Chemistry

The most common argument against these treatments is that they compensate for poor hygiene earlier in production — that a strong wash at the end permits a dirtier process upstream. It is an intuitive argument. It is also, in that strong causal form, untested, and this paper does not assert it.

What the evidence does support is narrower and still substantial.

Human illness tracks the live-bird reservoir

Havelaar and colleagues (2013) found that EU campylobacteriosis incidence was “significantly correlated with the prevalence of Campylobacter spp. in broiler chickens” and salmonellosis incidence “significantly correlated with the prevalence of Salmonella Enteritidis in laying hens.” Human disease burden follows what is in the animals, not what is applied at the end of the line.

Attacking the reservoir produces measurable gains

EFSA’s 2019 assessment calculated that achieving a 1% target for Salmonella in laying hen flocks would avert 254,400 human cases (95% credible interval 98,540–602,700) versus 2016 — a 53.4% reduction in layer-attributable salmonellosis across 23 Member States. Denmark’s flock-level control program, documented by Wegener and colleagues (2003), saved Danish society US$25.5 million in 2001 against control costs of US$14.1 million.

But EFSA is equally clear about the limits: an impact of Salmonella control programs “on the prevalence of Campylobacter in broiler flocks … is not expected.” Reservoir control is pathogen-specific. EU campylobacteriosis has risen — 55.3 per 100,000 in 2024, up 11.9% on 2023.

The decoupling in the U.S. data

The single most suggestive piece of evidence is USDA’s own. The withdrawn 2024 proposal stated that current performance standards have reduced contamination but have “yet to have an observable impact on Salmonella illnesses” — CDC’s 2019 rate of 17.1 per 100,000 was 14% above the 2006–2008 baseline, against a Healthy People 2030 target of 11.5.

Measured carcass contamination improved. Human illness did not follow. That is precisely the pattern one would expect if interventions were improving the numbers on the sampling sheet faster than they were improving actual risk — which is what Sections 5 and 6 independently document.

Current measured contamination, on both sides

Measure	U.S. (FSIS, Apr 2025 – Mar 2026)	EU (EFSA baseline survey, 2008)
Salmonella, broiler carcasses	3.53% (95% CI 3.01–4.14)	15.7%
Campylobacter, broiler carcasses	23.84% (95% CI 21.22–26.66)	75.8%
Salmonella, chicken parts	7.08% (95% CI 6.23–8.03)	—
Salmonella, comminuted chicken	42.62% (95% CI 30.48–55.73)	—

One U.S. figure in Table 4 warrants separate emphasis. Comminuted chicken — ground chicken and similar products — carries measured Salmonella prevalence of 42.62%, and 56.76% of establishments producing it exceed their own performance standard. A majority of plants failing, in the product category with the highest contamination, is not a marginal finding.

10. Worker Exposure

The clearest documented human harm associated with these chemicals is occupational, and it is almost entirely absent from the consumer-facing debate.

FSIS’s own hazard information sheet states that peroxyacetic acid vapor and mist “may sometimes cause eye, nose, throat and respiratory irritation,” and — notably — that there are no OSHA standards and no validated OSHA or NIOSH air sampling methods for PAA. Industry defaults to an ACGIH short-term exposure limit of 0.4 ppm over 15 minutes.

NIOSH evaluated peracetic acid exposure among federal poultry inspectors in 2017 (HHE 2015-0130-3290), finding low airborne concentrations in the evisceration department with some employees reporting symptoms. A more recent NIOSH evaluation published in February 2026 measured one employee at 0.41 ppm over 15 minutes, exceeding the exposure limit, with area samples up to 0.53 ppm and roughly half of participating employees reporting at least one work-related symptom, most commonly eye and nasal irritation. That evaluation was conducted at a beverage manufacturing facility, not a poultry plant, and we include it as the most recent quantitative NIOSH finding rather than as poultry evidence.

A worker in a plant applying peroxyacetic acid at up to 2,000 ppm is exposed to a substance with no enforceable federal airborne standard and no validated measurement method. That is a disclosure gap of a different kind, and a more consequential one than anything documented on the consumer side.

11. Limitations and Evidence Quality

Every factual claim in this paper is attributed to a named peer-reviewed paper, an official scientific-agency assessment, or a primary legal instrument. Citations were checked against Crossref, PubMed and Europe PMC. In the course of that verification, five commonly circulated citations in this literature were found to contain errors — including two misattributed first authors and one figure reporting the best-performing antimicrobial as among the worst. Corrected forms are used throughout.

The following limitations are stated so that nothing here is read as stronger than it is.

• No verified FSIS limit for chlorine, cetylpyridinium chloride or trisodium phosphate. The complete FSIS “safe and suitable ingredients” table could not be retrieved. Table 1 is therefore incomplete.
• The Navarre et al. (2026) full text is paywalled. The abstract quoted is verbatim and reliable; methods detail has not been reviewed. The accepted manuscript is licensed to become open in August 2026.
• The EU side of Table 4 is seventeen years old. No current harmonized EU carcass-prevalence survey comparable to the 2008 baseline was located. This is the largest single weakness in the comparison.
• Several EFSA opinions were assessed at abstract level only, the publisher having blocked retrieval — specifically the 2015 chlorate opinion, the 2014 peroxyacetic acid opinion, the 2019 phosphates re-evaluation, and the 2008 antimicrobial resistance opinion.
• The Highmore et al. (2018) VBNC study used spinach, not poultry. It establishes mechanism at chlorine concentrations within the poultry range but is not a poultry study.
• Claims we specifically do not make: that these washes suppress spoilage organisms while pathogens survive; that chlorine dioxide induces VBNC states; that chemical decontamination causes degraded upstream hygiene; or that EU incidence rates demonstrate the superiority of the EU approach. None is supported by evidence we could locate.

12. What This Means for Labels

Reading the evidence as a whole, three conclusions follow for anyone concerned with what a meat label communicates.

First, the popular framing is wrong, and correcting it strengthens rather than weakens the case for disclosure. The toxicological evidence does not support treating chlorine-washed chicken as dangerous to eat. A transparency argument built on that premise is built on the one part of the evidence base that will not hold. The defensible argument is about effectiveness, measurement integrity, and the consumer’s inability to know.

Second, the case for disclosure does not depend on the treatments being harmful. It depends on them being consequential and undisclosed. They affect shelf life, product handling, the reliability of safety verification data, and — at 2,000 ppm in a chiller — worker health. A processing step with those properties, applied at concentrations spanning more than an order of magnitude, with no requirement to say which chemical was used or whether one was used at all, is a genuine information gap regardless of its toxicology.

Third, the measurement finding reframes what safety data means. Enforcement statistics, performance standards and prevalence figures are the substrate of evidence-based labeling. Section 6 documents that these numbers are measurably affected by the interventions they are meant to evaluate — by a factor of roughly three when the sampling buffer changed, and by up to 1.0 log where nonculturable survivors go uncounted. Any transparency framework that relies on such data has to account for that.

Farm Animal Transparency’s position is not that antimicrobial washes should be prohibited. Peracetic acid demonstrably reduces pathogen loads, and immersion chilling without any intervention would be worse than immersion chilling with one. The position is that a consumer should be able to find out what was applied to the food they are buying — and that at present, on a U.S. poultry label, they cannot.

Sources

Official Risk Assessments and Agency Documents

1. EFSA Panel on Food Additives, Flavourings, Processing Aids and Materials in Contact with Food (2006). “Opinion … related to Treatment of poultry carcasses with chlorine dioxide, acidified sodium chlorite, trisodium phosphate and peroxyacids.” The EFSA Journal (2005) 297, 1–27. DOI 10.2903/j.efsa.2006.297.
2. EFSA Panel on Biological Hazards (2008). “Assessment of the possible effect of the four antimicrobial treatment substances on the emergence of antimicrobial resistance.” EFSA Journal 2008;659:2–26. DOI 10.2903/j.efsa.2008.659
3. EFSA (2010). “Analysis of the baseline survey on the prevalence of Campylobacter in broiler batches and of Campylobacter and Salmonella on broiler carcasses in the EU, 2008 — Part A.” EFSA Journal 8(3):1503. DOI 10.2903/j.efsa.2010.1503
4. EFSA Panel on Biological Hazards (2014). “Scientific Opinion on the evaluation of the safety and efficacy of peroxyacetic acid solutions for reduction of pathogens on poultry carcasses and meat.” EFSA Journal 12(3):3599.
5. EFSA CONTAM Panel (2015). “Risks for public health related to the presence of chlorate in food.” EFSA Journal 13(6):4135. DOI 10.2903/j.efsa.2015.4135
6. EFSA ANS Panel (2019). “Re-evaluation of phosphoric acid–phosphates as food additives.” EFSA Journal 17(6):5674. DOI 10.2903/j.efsa.2019.5674
7. EFSA Panel on Biological Hazards (2019). “Salmonella control in poultry flocks and its public health impact.” EFSA Journal 17(2):e05596. DOI 10.2903/j.efsa.2019.5596
8. EFSA and ECDC (2025). “The European Union One Health 2024 Zoonoses Report.” EFSA Journal 23(12):e9759. DOI 10.2903/j.efsa.2025.9759
9. FAO/WHO (2009). Benefits and risks of the use of chlorine-containing disinfectants in food production and food processing. Report of a joint FAO/WHO expert meeting, Ann Arbor, MI, 27–30 May 2008. Rome. ISBN 978 92 4 159894 1.
10. FAO (2018). Biocides and Antimicrobial Resistance — Summary Report of an FAO Meeting of Experts. FAO Antimicrobial Resistance Working Group.
11. Cressey, P., Nokes, C., Lake, R. (2008). Chlorinated Compounds Formed During Chlorine Wash of Chicken Meat. ESR Client Report FW0883 for the New Zealand Food Safety Authority.
12. CDC (2026). FoodNet 2024 Preliminary Data. Foodborne Diseases Active Surveillance Network.
13. CDC (2024). “Reported Incidence of Infections Caused by Pathogens Transmitted Commonly Through Food: Impact of Increased Use of Culture-Independent Diagnostic Tests — FoodNet, 1996–2023.” MMWR 73(26).
14. UK Food Standards Agency (2021). A microbiological survey of campylobacter contamination in fresh whole UK-produced chilled chickens at retail sale (Y6).
15. USDA FSIS. Directive 7120.1 Revision 59, Safe and Suitable Ingredients Used in the Production of Meat, Poultry, and Egg Products, 7 August 2024.
16. USDA FSIS. Directive 10,250.2, Performance Standards Salmonella Verification Program for Raw Poultry Products.
17. USDA FSIS. Sampling Results for FSIS Regulated Products (rolling 12-month dataset, 1 April 2025 – 31 March 2026; page updated 24 April 2026).
18. USDA FSIS. Salmonella Verification Testing Program Monthly Posting — establishment categorization aggregate, 5 June 2026.
19. USDA FSIS. Health Hazard Information Sheet — Peroxyacetic Acid (PAA), ESHG-Health-03.00.
20. Burton, N.C., Gibbins, J. (2017). Evaluation of Peracetic Acid Exposure Among Federal Poultry Inspectors. NIOSH Health Hazard Evaluation Report 2015-0130-3290.
21. Charles, M., Rinsky, J.L., Grant, M., Dunn, K.H. (2026). NIOSH Health Hazard Evaluation Report 2023-0033-3427.

Legal Instruments

22. Regulation (EC) No 853/2004 laying down specific hygiene rules for food of animal origin, OJ L 139, 30.4.2004, p. 55, Article 3(2).
23. Regulation (EC) No 852/2004 on the hygiene of foodstuffs, OJ L 139, 30.4.2004, p. 1.
24. Commission Regulation (EC) No 2073/2005 on microbiological criteria for foodstuffs, OJ L 338, 22.12.2005, p. 1.
25. Council Decision 2009/121/EC of 18 December 2008 rejecting the Commission proposal on antimicrobial substances to remove surface contamination from poultry carcasses.
26. Commission Regulation (EU) No 101/2013 of 4 February 2013 concerning the use of lactic acid to reduce microbiological surface contamination on bovine carcases.
27. Commission Regulation (EU) 2015/1474 of 27 August 2015 concerning the use of recycled hot water to remove microbiological surface contamination from carcases.
28. The Specific Food Hygiene (Regulation (EC) No. 853/2004) (Amendment) (EU Exit) Regulations 2019, S.I. 2019/1247.
29. 9 C.F.R. § 424.21 — Use of food ingredients and sources of radiation.
30. 21 C.F.R. § 173.325 — Acidified sodium chlorite solutions.
31. 21 C.F.R. § 173.370 — Peroxyacids.
32. USDA FSIS. “Salmonella Framework for Raw Poultry Products” — proposed rule, 89 FR 64678, 7 August 2024, Docket FSIS-2023-0028.
33. USDA FSIS. “Salmonella Framework for Raw Poultry Products” — withdrawal, 90 FR 17344, 25 April 2025.
34. USDA FSIS. “Exploring Practical Strategies To Reduce Salmonella in Poultry Products” — notice of public meeting, 90 FR 55297, 2 December 2025.

Peer-Reviewed Literature

35. Alonso-Hernando, A., Capita, R., Prieto, M., Alonso-Calleja, C. (2009). “Adaptation and cross-adaptation of Listeria monocytogenes and Salmonella enterica to poultry decontaminants.” The Journal of Microbiology 47(2):142–146. DOI 10.1007/s12275-008-0237-5
36. Bauermeister, L.J., Bowers, J.W.J., Townsend, J.C., McKee, S.R. (2008). “The Microbial and Quality Properties of Poultry Carcasses Treated with Peracetic Acid as an Antimicrobial Treatment.” Poultry Science 87(11):2390–2398. DOI 10.3382/ps.2008-00087
37. Bourassa, D.V., Lapidus, J.L., Kennedy-Smith, A.E., Morey, A. (2019). “Efficacy of neutralizing buffered peptone water for recovery of Salmonella, Campylobacter, and Enterobacteriaceae from broiler carcasses … with peroxyacetic acid.” Poultry Science 98(1):393–397. DOI 10.3382/ps/pey361
38. Boyce, J.M. (2023). “Quaternary ammonium disinfectants and antiseptics: tolerance, resistance and potential impact on antibiotic resistance.” Antimicrobial Resistance & Infection Control 12:32. DOI 10.1186/s13756-023-01241-z
39. Ferreira, S. (2026). “When Disinfection Fails: Biocide Tolerance as a Driver of Campylobacter Persistence and Resistance.” Antibiotics 15(4):357. DOI 10.3390/antibiotics15040357
40. Gamble, G.R., Berrang, M.E., Buhr, R.J., Hinton, A. Jr., Bourassa, D.V., Johnston, J.J., Ingram, K.D., Adams, E.S., Feldner, P.W. (2016). “Effect of simulated sanitizer carryover on recovery of Salmonella from broiler carcass rinsates.” Journal of Food Protection 79(5):710–714. DOI 10.4315/0362-028X.JFP-15-461
41. Gamble, G.R., Berrang, M.E., et al. (2017). “Neutralization of Bactericidal Activity Related to Antimicrobial Carryover in Broiler Carcass Rinse Samples.” Journal of Food Protection 80(4):685–691. PMID 28304195
42. Gichure, J.N., Kamau Njage, P.M., Wambui, J.M., Dykes, G.A., Buys, E.M., Coorey, R. (2022). “Systematic-review and meta-analysis on effect of decontamination interventions on prevalence and concentration of Campylobacter spp. during primary processing of broiler chickens.” Food Microbiology 102:103923. DOI 10.1016/j.fm.2021.103923
43. Havelaar, A.H., Ivarsson, S., Löfdahl, M., Nauta, M.J. (2013). “Estimating the true incidence of campylobacteriosis and salmonellosis in the European Union, 2009.” Epidemiology and Infection 141(2):293–302.
44. Highmore, C.J., Warner, J.C., Rothwell, S.D., Wilks, S.A., Keevil, C.W. (2018). “Viable-but-Nonculturable Listeria monocytogenes and Salmonella enterica Serovar Thompson Induced by Chlorine Stress Remain Infectious.” mBio 9(2):e00540-18. DOI 10.1128/mBio.00540-18
45. Kataria, J., Vaddu, S., Novoa Rama, E., Sidhu, G., Thippareddi, H., Singh, M. (2020). “Evaluating the efficacy of peracetic acid on Salmonella and Campylobacter on chicken wings at various pH levels.” Poultry Science 99:5137–5142. DOI 10.1016/j.psj.2020.06.070
46. Leone, C., Xu, X., Mishra, A., Thippareddi, H., Singh, M. (2024). “Interventions to reduce Salmonella and Campylobacter during chilling and post-chilling stages of poultry processing: a systematic review and meta-analysis.” Poultry Science 103(4):103492. DOI 10.1016/j.psj.2024.103492
47. Mohammad, Z., Hasan, A., Kerth, C., Riley, D., Taylor, T. (2018). “Increased Effectiveness of Microbiological Verification by Concentration-Dependent Neutralization of Sanitizers Used in Poultry Slaughter and Fabrication Allowing Salmonella enterica Survival.” Foods 7(3):32. DOI 10.3390/foods7030032
48. Nagel, G.M., Bauermeister, L.J., Bratcher, C.L., Singh, M., McKee, S.R. (2013). “Salmonella and Campylobacter reduction and quality characteristics of poultry carcasses treated with various antimicrobials in a post-chill immersion tank.” International Journal of Food Microbiology 165(3):281–286. DOI 10.1016/j.ijfoodmicro.2013.05.016
49. Navarre, A., Quintana-Pérez, F.M., Kovac, J. (2026). “Peroxyacetic acid treatment significantly reduced Campylobacter jejuni culturability but not viability on chicken breasts.” Food Control 180:111652. DOI 10.1016/j.foodcont.2025.111652
50. Purevdorj-Gage, L., Nixon, B., Bodine, K., Xu, Q., Doerrler, W.T. (2018). “Differential Effect of Food Sanitizers on Formation of Viable but Nonculturable Salmonella enterica in Poultry.” Journal of Food Protection 81(3):386–393. DOI 10.4315/0362-028X.JFP-17-335
51. Rothrock, M.J. / Bourassa, D.V. et al. (2022). “Consequences of Implementing Neutralizing Buffered Peptone Water in Commercial Poultry Processing on the Microbiota of Whole Bird Carcass Rinses.” Frontiers in Microbiology 13:813461. DOI 10.3389/fmicb.2022.813461
52. Scallan, E., Hoekstra, R.M., Angulo, F.J., Tauxe, R.V., Widdowson, M-A., Roy, S.L., Jones, J.L., Griffin, P.M. (2011). “Foodborne Illness Acquired in the United States—Major Pathogens.” Emerging Infectious Diseases 17(1):7–15.
53. Thames, H.T., Theradiyil Sukumaran, A. (2020). “A Review of Salmonella and Campylobacter in Broiler Meat: Emerging Challenges and Food Safety Measures.” Foods 9(6):776. DOI 10.3390/foods9060776
54. Weerasooriya, G., McWhorter, A.R., Khan, S., Chousalkar, K.K. (2022). “Effects of Sublethally Injured Campylobacter jejuni in Mice.” Microbiology Spectrum 10(4):e00690-22. DOI 10.1128/spectrum.00690-22
55. Wegener, H.C., Hald, T., Lo Fo Wong, D., Madsen, M., Korsgaard, H., Bager, F., Gerner-Smidt, P., Mølbak, K. (2003). “Salmonella Control Programs in Denmark.” Emerging Infectious Diseases 9(7):774–780.
56. Williams, M.S., Ebel, E.D., Hretz, S.A., Golden, N.J. (2018). “Adoption of Neutralizing Buffered Peptone Water Coincides with Changes in Apparent Prevalence of Salmonella and Campylobacter of Broiler Rinse Samples.” Journal of Food Protection 81(11):1851–1863. DOI 10.4315/0362-028X.JFP-18-124
57. Wu-Chen, R.A., Feng, J., Elhadidy, M., Nambiar, R.B., Liao, X., Yue, M., Ding, T. (2023). “Long-term exposure to food-grade disinfectants causes cross-resistance to antibiotics in Salmonella enterica serovar Typhimurium strains with different antibiograms and sequence types.” Antimicrobial Resistance and Infection Control 12(1):145. DOI 10.1186/s13756-023-01333-w
58. Xiao, X., Bai, L., Wang, S., Liu, L., Qu, X., Zhang, J., Xiao, Y., Tang, B., Li, Y., Yang, H., Wang, W. (2022). “Chlorine Tolerance and Cross-Resistance to Antibiotics in Poultry-Associated Salmonella Isolates in China.” Frontiers in Microbiology 12:833743. DOI 10.3389/fmicb.2021.833743
59. Zhang, L., Garner, L.J., McKee, S.R., Bilgili, S.F. (2018). “Effectiveness of Several Antimicrobials Used in a Postchill Decontamination Tank against Salmonella and Campylobacter on Broiler Carcass Parts.” Journal of Food Protection 81(7):1134–1141. DOI 10.4315/0362-028X.JFP-17-507

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Farm Animal Transparency (FAT) is an independent, evidence-based project focused on clarity and disclosure in U.S. meat labeling. farmanimaltransparency.com

Last reviewed: July 2026. Prepared with the assistance of AI. All sources are peer-reviewed literature, official scientific-agency assessments, or primary legal instruments; no advocacy-group, trade-association, or trade-press source is used as evidence.

© 2026 Farm Animal Transparency. All rights reserved.