Agency Response Letter GRAS Notice No. GRN 000435

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CFSAN/Office of Food Additive Safety

February 22, 2013

Alexander Sulakvelidze, Ph.D.
Intralytix, Inc.
The Columbus Center
701 E. Pratt Street
Baltimore, MD 21202

Re: GRAS Notice No. GRN 000435

Dear Dr. Sulakvelidze:

The Food and Drug Administration (FDA) is responding to the notice, dated June 25, 2012, that you submitted in accordance with the agency’s proposed regulation, proposed 21 CFR 170.36 (62 FR 18938; April 17, 1997; Substances Generally Recognized as Safe (GRAS); the GRAS proposal). FDA received the notice on July 5, 2012, filed it on July 6, 2012, and designated it as GRAS Notice No. GRN 000435.

The subject of the notice is a preparation consisting of six bacterial monophage specific to Salmonella enterica (monophage cocktail). The notice informs FDA of the view of Intralytix, Inc. (Intralytix) that monophage cocktail is GRAS, through scientific procedures, for use as an antimicrobial in certain poultry products, fish, shellfish, and fresh and processed fruits and vegetables at 107 plaque-forming units (PFU) per gram (g) of food.

Our use of “monophage cocktail” in this letter should not be considered an endorsement or recommendation of that term as an appropriate common or usual name for the purpose of declaring the substance in the ingredient statement of foods that contain that ingredient. Title 21 CFR 101.4 states that each ingredient must be declared by its common or usual name. In addition, 21 CFR 102.5 outlines general principles to use when establishing common or usual names for nonstandardized foods. For questions related to issues associated with labeling and the appropriate common or usual name of a food, contact the Office of Nutrition, Labeling, and Dietary Supplements (ONLDS) in the Center for Food Safety and Applied Nutrition.

The monophage cocktail consists of a preparation of equal titer of six individually purified lytic phage isolated from water sources. All phage are effective against specific S. enterica serotypes. Each phage in the monophage cocktail is prepared using an aerobic fermentation process in which the phage and the appropriate host are grown in a culture medium containing soy and yeast-derived products. The cells are lysed and the lysates are purified by removing remaining cellular material. Each phage is concentrated approximately ten-fold and washed. The final preparation consists of each of the filtered six phage combined with 0.1M sodium chloride, and with equal and minimum lytic titer of (10.0 ± 0.33) log10 PFU per milliliter (mL). The shelf-life of the monophage cocktail is intended to be one year when stored at 2-6 °C, in a dark, UV-protected area.

Intralytix provides specifications for the individual phage and the monophage cocktail. The specifications for the individual phage include titer (≥ (10.0 ± 0.33) log10 PFU/mL), bacterial sterility and genotypic fingerprinting (matches reference bands). In addition to titer and bacterial sterility, monophage cocktail also includes specifications for identity (lyses all reference strains) and endotoxin limit (≤ 25,000 ELISA Units (EU) per mL (at ≈ 9.0 ± 0.33 log10 PFU/mL)).

Intralytix estimates dietary exposure to monophage cocktail from the intended use and use level for the US population based on the per capita Food Availability Data System provided by the United States Department of Agriculture’s (USDA’s) Economic Research Services. Monophage cocktail is intended to be used at a maximum final concentration of 107 PFU/g of food. This translates to an estimated consumption of 3.98 micrograms (μg) per person per day. Based on a 3-kilogram (kg) diet per day, Intralytix estimates daily exposure to monophage cocktail to be 1.33 μg/kg of the diet. Intralytix also estimates daily exposure to endotoxins from the intended use and use levels of the monophage cocktail to be negligible.(1)

Intralytix has sequenced the entire genome of each phage in monophage cocktail and found that:

  • No genes expressing known toxins have been identified among the open reading frames of the annotated genomes of any of the six phage.
  • No 16S ribosomal RNA genes have been identified among annotated genomes of any of the six phage.
  • No genes conferring antibiotic resistance have been identified among annotated genomes of any of the six phage.

As part of the notice, Intralytix discusses its review of the published literature regarding bacteriophage in general. Intralytix concludes:

  • Phage are ubiquitous. They are commonly consumed in drinking water and in various foods. The abundance of phage in the environment, and the continuous exposure of animals to them, explains the tolerance of mammalian organisms to phage.
  • The biology of phage has been exhaustively studied. These studies have established that phage are obligate intracellular parasites of bacteria and cannot infect humans or other animals. Phage are common commensals of the human gut, and they are likely to play an important role in regulating the diversity and population structure of various bacteria in human GI tracts. Because of the high specificity of phage to their hosts and because of the extremely common exposure of humans and animals to them, phage do not deleteriously affect the GI microflora.
  • No adverse immunologic or allergic sequelae have ever been reported from human or animal exposure to phage.

Standards of Identity

In the notice, Intralytix states its intention to use monophage cocktail in several food categories, including foods for which standards of identity exist, located in Title 21 of the Code of Federal Regulations. We note that an ingredient that is lawfully added to food products may be used in a standardized food only if it is permitted by the applicable standard of identity.

Allergen Labeling

The Food Allergen Labeling and Consumer Protection Act of 2004 (FALCPA) amends the Federal Food, Drug, and Cosmetic Act (FD&C Act) to require that the label of a food that is or contains an ingredient that bears or contains a “major food allergen” declare the presence of the allergen (section 403(w)). FALCPA defines a “major food allergen” as one of eight foods or food groups (i.e., milk, eggs, fish, Crustacean shellfish, tree nuts, peanuts, wheat, and soybeans) or a food ingredient that contains protein derived from one of those foods. Monophage cocktail produced using soy-based peptone medium in the fermentation process, may require labeling under FALCPA, because it may contain protein derived from soybeans. Although issues associated with labeling food are the responsibility of ONLDS, issues associated with FALCPA exemptions are the responsibility of the Food Allergen Coordinator in the Office of Food Additive Safety.

Use in Products under USDA Jurisdiction

During its evaluation of GRN 000435, FDA consulted with the Risk, Innovations, and Management Division of the Food Safety and Inspection Service (FSIS) of the USDA. Under the Federal Meat Inspection Act, Poultry Products Inspection Act, and the Egg Products Inspection Act, FSIS is responsible for determining the efficacy and suitability of food ingredients in meat, poultry, and egg products as well as prescribing safe conditions of use. Suitability relates to the effectiveness of the ingredient in performing the intended purpose of use and the assurance that the conditions of use will not result in an adulterated product, or one that misleads consumers.

FSIS has determined that Intralytix has provided sufficient data to support that monophage cocktail is suitable for use as an antimicrobial and processing aid in the production of certain poultry products as described below, to reduce Salmonella. FSIS also notes that the monophage cocktail would be applied as a spray at ≈ 106 to ≈ 107 PFU/g in ready-to-eat poultry products prior to slicing, raw poultry prior to grinding, and raw poultry after grinding. For the notified poultry products treated with monophage cocktail, FSIS states that there will be no requirement for labeling, so long as the conditions of intended use are satisfied.

Any additional questions regarding monophage cocktail’s intended use in poultry products should be directed to Dr. William Shaw, Risk, Innovation, and Management Division, Office of Policy, Program, and Development, Food Safety and Inspection Service, via email at

Section 301(ll) of the FD&C Act

The Food and Drug Administration Amendments Act of 2007, which was signed into law on September 27, 2007, amends the FD&C Act to, among other things, add section 301(ll). Section 301(ll) of the FD&C Act prohibits the introduction or delivery for introduction into interstate commerce of any food that contains a drug approved under section 505 of the FD&C Act, a biological product licensed under section 351 of the Public Health Service Act, or a drug or a biological product for which substantial clinical investigations have been instituted and their existence made public, unless one of the exemptions in section 301(ll)(1)-(4) applies. In its review of Intralytix’s notice that monophage cocktail is GRAS for the intended uses, FDA did not consider whether section 301(ll) or any of its exemptions apply to foods containing monophage cocktail. Accordingly, this response should not be construed to be a statement that foods that contain monophage cocktail, if introduced or delivered for introduction into interstate commerce, would not violate section 301(ll).


Based on the information provided by Intralytix, as well as other information available to FDA, the agency has no questions at this time regarding Intralytix’s conclusion that monophage cocktail is GRAS under the intended conditions of use. The agency has not, however, made its own determination regarding the GRAS status of the subject use of monophage cocktail. As always, it is the continuing responsibility of Intralytix to ensure that food ingredients that the firm markets are safe, and are otherwise in compliance with all applicable legal and regulatory requirements.

In accordance with proposed 21 CFR 170.36(f), a copy of the text of this letter responding to GRN 000435, as well as a copy of the information in this notice that conforms to the information in the GRAS exemption claim (proposed 21 CFR 170.36(c)(1)), is available for public review and copying at


Dennis M. Keefe, Ph.D.
Office of Food Additive Safety
Center for Food Safety and Applied Nutrition

cc: William K. Shaw Jr., Ph.D.
Stop Code 3782, Patriots Plaza III
1400 Independence Ave. SW
Washington, DC 20250-3700

(1)FDA notes that Gram-negative bacteria routinely produce endotoxins; these toxins are ubiquitous in the environment and are constantly consumed by humans and are harmless via the oral route.

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