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The FDA has recognized the antimicrobial activity of hypochlorous acid in its Guide to Minimize Microbial Food Safety Hazards of Fresh-cut Fruits and Vegetables published in February of 2008.

What is a Food Contact Notication (FCN)?

A food contact notification (FCN) is the primary method by which the Food and Drug Administration (FDA) regulates food additives that are food contact substances (FCSs). An FCS is any substance that is intended for use as a component of materials used in manufacturing, packing, packaging, transporting, or holding food if such use of the substance is not intended to have any technical effect in such food. Notifications for an FCS must contain sufficient scientific information to demonstrate that the substance that is the subject of the notification is safe for the intended use (sec. 409(h) of the Act).

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Because the safety standard is the same for all food additives, whether subject to the petition process or the FCN process, information in an FCN should be comparable to that recommended for inclusion in a food additive petition or in a “Threshold of Regulation” submission (See 21 CFR 170.39). According to Section 409(h)(1)(C) of the Federal Food, Drug, and Cosmetic Act, food contact substance notifications (FCNs) are effective only for the listed manufacturer and its customers. Other manufacturers must submit their own FCN for the same food contact substance and intended use.

What does “GRAS” mean?

“GRAS” is an acronym for the phrase Generally Recognized As Safe. Under sections 201(s) and 409 of the Federal Food, Drug, and Cosmetic Act (the Act), any substance that is intentionally added to food is a food additive, that is subject to premarket review and approval by FDA, unless the substance is generally recognized, among qualified experts, as having been adequately shown to be safe under the conditions of its intended use.

What is the criteria for GRAS status?

Under 21 CFR 170.30(b), general recognition of safety through scientific procedures requires the same quantity and quality of scientific evidence as is required to obtain approval of the substance as a food additive and ordinarily is based upon published studies, which may be corroborated by unpublished studies and other data and information.

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In what way is the criteria for the use of a substance to be GRAS similar to that for the approved use of a food additive?

Regardless of whether the use of a substance is a food additive use or is GRAS, there must be evidence that the substance is safe under the conditions of its intended use. FDA has defined “safe” (21 CFR 170.3(i)) as a reasonable certainty in the minds of competent scientists that the substance is not harmful under its intended conditions of use. The specific data and information that demonstrate safety depend on the characteristics of the substance, the estimated dietary intake, and the population that will consume the substance.

Must the FDA approve GRAS substances?

No. If the use of a food substance is GRAS, it is not subject to the premarket review and approval requirement by FDA.

Guide to Minimize
Microbial Food
Safety Hazards

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The FDA has recognized the antimicrobial activity of hypochlorous acid in its Guide to Minimize Microbial Food Safety Hazards of Fresh-cut Fruits and Vegetables published in February of 2008. When used appropriately with adequate quality water, antimicrobial chemicals help minimize the potential for microbial contamination of processing water and subsequent cross contamination of the product.

The effectiveness of an antimicrobial agent, as well as the amount that should be used, depends on the treatment conditions, such as water temperature, acidity [pH], water hardness, contact time, amount and rate of product throughput, type of product, water to product ratio, amount of organic material, and the resistance of pathogens to the particular antimicrobial agent. For example, the antimicrobial activity of a chlorine-based disinfectant depends on the amount of hypochlorous acid (also called “free chlorine”) present in the water.

The amount of hypochlorous acid in the water depends upon the pH of the water, the amount of organic material in the water, and, to some extent, the temperature of the water. If the amount of hypochlorous acid is not maintained when the amount of organic material increases, the antimicrobial agent may lose effectiveness in maintaining water quality.

If a fresh-cut processor uses a chlorine containing compound as a disinfectant, we recommend that the processor monitor the processing water for free chlorine or hypochlorous acid concentrations. As another example, the measurement of Oxidation-Reduction Potential (ORP) is used as an indicator of the activity of any antimicrobial agent that is an oxidizer and as a measure of the agent’s effectiveness during processing. Variables that affect antimicrobial activity during processing directly affect the ORP value and may also be used to determine the effectiveness of these oxidizers such as hypoorous acid, hypobromous acid, chlorine dioxide, ozone, and peroxides.

We recommend that fresh-cut processors consider options for maintaining the quality of water most appropriate for their individual operations. Producers may wish to contact a local agricultural extension agent, their chemical supplier, or a food safety consultant for help in deciding what water treatment chemicals to use. In addition, processors may refer to 21 CFR 173.315, “Chemicals used in washing or to assist in the peeling of fruits and vegetables,” for additional information about chemicals approved for use in wash water.

Control of
Microbial Hazards
on Fresh and
Fresh-Cut Produce

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Liquid chlorine and hypochlorites are generally used in the 50 to 200 ppm concentration range with a contact time of 1 to 2 min to sanitize produce surfaces and processing equipment. Higher concentrations have been investigated for use on seeds for sprout production. Hypochlorous acid (HOCl) is the form of free available chlorine that has the highest bactericidal activity against a broad range of microorganisms. In aqueous solutions, the equilibrium between hypochlorous acid (HOCl) and the hypochlorite ion (OCl-) is pH dependent with the concentration of HOCl increasing as pH decreases.