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Guidance for Processing Reduced Oxygen Packaged (ROP) of Raw, Frozen, Seafood in Retail Operations

Keith R. Schneider, W. Steve Otwell, Victor Garrido, and Ray Mobley

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This recommended guidance is for frozen seafood that is packaged in a manner that reduces the amount of oxygen in the package below the level normally found in air (anaerobic condition). This condition can alter the growth of spoilage bacteria that normally requires atmospheric oxygen levels (aerobic conditions) for growth. Reduced oxygen packaging (ROP) can include vacuum packaging, and modified or controlled atmospheric packaging (MAP or CAP). These packaging methods can provide the benefit of protecting the product during frozen storage while providing attractive, easy to handle packages with odor control, but in certain circumstances it can also present anaerobic conditions that are favorable for growth and toxin production by a potentially lethal pathogen, Clostridium botulinum.

Certain types of C. botulinum bacteria common to seafood, due to their freshwater and saltwater environments, can grow when products are exposed to temperatures above customary refrigeration. Previous studies have demonstrated that certain C. botulinum associated with seafood can grow at temperatures as low as 38°F (3.3°C) and prolonged storage at 38°F (approx. > 25 days) could result in dangerous, toxic conditions (1). Their growth and toxin production will increase as the exposure time and temperature increases. Due to the serious consequences with the C. botulinum toxins and the potential for pathogen growth while the seafood remains in anaerobic conditions, the use of ROP in retail processing of seafood is restricted to frozen seafood. Frozen storage prevents potential growth and toxin production by C. botulinum.

The most current version of the Food Code issued by the U.S. Public Health Service, FDA, recommends food establishments should not be allowed to package fish in ROP unless the fish is frozen before, during and after packaging (Food Code Section 3.50 2.12-C). This recommendation is qualified to apply to all seafoods that are considered fresh, non-frozen or not previously processed to reduce the water activity (aw) or acidity (pH) of the seafood such that it would prevent potential hazards due to C. botulinum. Note that regular, dedicated food processing operations with appropriate HACCP plans are allowed to use ROP with non-frozen seafood intended for retail distribution if their HACCP plans include at least two barriers to control the growth and toxin formation of C. botulinum (21 CFR Part 123; source 

1 Skinner, G.E. and J.W. Larkin. 1998. Conservative prediction of time to Clostridium botulinum toxin formation for use with time-temperature indicators to ensure the safety of food. J. Food Protection 61 (9) 1998: 1154 –1160.


This guidance has been prepared in response to a notable increase in on-site retail processing (manufacturing) of foods traditionally processed in controlled plant environments. Such retail processing can involve, but is not limited to acidifying, smoking, drying, fermenting, curing, reduced oxygen packaging, and other operations that are traditionally done at a food manufacturing plant level. The key distinction for processing as related to this guidance is that the processing occurs on-site in the retail setting. This guidance is intended for retailers and regulatory personnel to help understand the controls to implement in a retail operation in order to process and sell safe food products. It can be referenced in developing considerations for variances for any exception or special provision to state or local food safety or sanitary codes. It addresses those special variances required by the FDA Food Code which may require HACCP plans for those jurisdictions that have adopted those portions of the FDA Food Code. In addition, it also applies to regulatory oversight and/or approval for regulatory overlap that may occur between the states processing requirements and the state or local retail food safety and sanitary codes. This guidance assumes retail compliance with applicable retail food codes, prerequisite standard sanitary operations procedures, and labeling requirements specified in 21 CFR 101. This guidance is not intended to replace or duplicate existing regulations, but it does offer a reference for more uniform practices.


This guidance is not a binding set of requirements. The information provided in the guidance are recommendations based on current science, commercial experience and practical considerations as assembled by the assigned committees and reviewed by a variety of selected experts and the Project Steering Committee. Use of these recommendations would likely result in retail processing practices that are acceptable to the pertinent authorities for food safety. Retail compliance and enforcement will remain within the interpretations and decisions of the pertinent state and local regulatory authorities.

Publication #FSHN0504

Release Date:February 27, 2019

Reviewed At:April 11, 2022

Related Experts

Garrido, Victor M

University of Florida

Schneider, Keith R.


University of Florida

Otwell, Steve


University of Florida

Related Topics

Fact Sheet

About this Publication

This document is FSHN0504, one of a series of the Food Science and Human Nutrition Department, UF/IFAS Extension. Original publication date February 2005. Visit the EDIS website at for the currently supported version of this publication.

About the Authors

Keith R. Schneider, professor, W. Steve Otwell, professor, and Victor Garrido, research coordinator and Food Science and Human Nutrition Department, University of Florida,Gainesville, FL 32611; and Ray Mobley, PhD, Florida A&M University.


  • Keith Schneider