Bulletin #3107, Reduced Oxygen Packaging (ROP): Requirements and Guidelines in Maine for Food Service

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By Jason Bolton, Ph.D. Assistant Extension Professor and Food Safety Specialist, University of Maine Cooperative Extension and Gulsun Akdemir Evrendilek, Associate Extension Professor and Seafood Technology and Food Safety Specialist, University of Maine Cooperative Extension.

Reviewed by Amanda Kinchla, Associate Extension Professor, Department of Food Science University of Massachusetts Amherst, Tom Jenkins, Inspector, Public Health Inspector at the State of Maine, and Joel Demers; Public Health Inspector Supervisor for the State of Maine.

For information about UMaine Extension programs and resources, visit extension.umaine.edu.
Find more of our publications and books at extension.umaine.edu/publications/.

microbiologist Glenn Boyd vacuum-seals hotdogs to get them ready for irradiation
Photo by Stephen Ausmus

Table of Contents

Background

Reduced Oxygen Packaging

Reduced Oxygen Packaging (ROP) is a critical technique used by food service establishments, grocery stores, and food manufacturers to extend the shelf life of perishable foods. By significantly reducing the oxygen within the packaging, ROP slows the growth of spoilage microorganisms, preserves food quality, extends shelf life, enhances storage efficiency, and minimizes food waste. However, this controlled environment can also pose a significant food safety hazard if not properly managed, as it can foster the growth of dangerous pathogens such as Clostridium botulinum and Listeria monocytogenes. ROP methods, including vacuum packaging, modified atmosphere packaging (MAP), controlled atmosphere packaging (CAP), and cook-chill or sous vide, are commonly employed for meats, seafood, dairy products, and ready-to-eat foods. This fact sheet is essential because, while ROP offers substantial benefits, the potential for severe foodborne illness underscores the necessity for rigorous safety protocols. This document aims to equip food service professionals with the knowledge and tools needed to implement ROP safely, emphasizing the importance of Hazard Analysis and Critical Control Points (HACCP) plans, strict temperature controls, proper cooling, and organized food labeling. By understanding and adhering to these best practices, we can mitigate the risks associated with ROP and ensure the safety of the food supply.

Due to these risks, ROP is subject to stringent food safety regulations. In Maine, food service establishments must comply with specific guidelines set by the Maine Food Code, which requires a HACCP plan for ROP operations. This ensures that businesses take necessary precautions, such as controlling storage temperatures, properly labeling packages, and following safe handling procedures to prevent bacterial growth.

Understanding the benefits and risks of ROP is essential for food service operators, retailers, and consumers. Proper implementation of ROP techniques and food safety best practices helps ensure that packaged foods remain safe while maintaining their freshness and quality.

Types of Reduced Oxygen Packaging

There are various reduced-oxygen packaging technologies. Each is designed to address specific food preservation needs, balancing food safety, shelf life, and quality. However, they all require careful monitoring to avoid potential food safety hazards, especially in environments that promote the growth of anaerobic pathogens. The following summarizes the various ROP techniques and highlights the advantages and limitations of each method.

Vacuum Packaging

Vacuum packaging involves removing air from the package and then hermetically sealing it to create an oxygen-deprived environment. This reduces the growth of aerobic microorganisms and oxidation, thereby extending the product’s shelf life.

  • Advantages
    • Extends shelf life by eliminating oxygen that promotes spoilage.Preserves flavor, texture, and nutrients.
    • Ideal for preventing freezer burn in frozen foods.
  • Disadvantages
    • Can foster the growth of anaerobic pathogens like C. botulinum if not properly stored.Can affect the visual appeal of some foods (e.g., discoloration).
    • Requires careful handling and temperature control to prevent safety issues.
  • Food Types
    • Meats, seafood, cheese, fruits, vegetables, ready-to-eat meals, and prepared foods.

Modified Atmosphere Packaging (MAP)

MAP replaces the air inside a package with a mixture of gases (typically nitrogen, carbon dioxide, and sometimes oxygen) to slow microbial growth and oxidation. This method is often used to extend the shelf life of perishable foods.

  • Advantages
    • Extends shelf life by altering the internal atmosphere, slowing microbial and chemical spoilage.Customizable gas mixtures for specific food products.
    • Maintains the product’s freshness and appearance.
  • Disadvantages
    • Requires specialized equipment for gas mixture and packaging.Can be expensive due to the need for gas generation and precise controls.
    • Not suitable for all products, particularly those sensitive to moisture or oxygen fluctuations.
  • Food Types
    • Fresh produce (e.g., fruits, vegetables), meats, seafood, dairy products, bakery items, and ready-to-eat meals.

Controlled Atmosphere Packaging (CAP)

CAP is an advanced packaging method where the gas composition within the package is actively controlled and monitored throughout storage. This technique is typically used for fresh produce to manage respiration rates and reduce aging.

  • Advantages
    • Provides the highest level of control over the internal atmosphere, which helps extend freshness and reduce spoilage.Effective for long-term storage of fruits and vegetables.
    • Reduces the need for preservatives.
  • Disadvantages
    • Requires continuous monitoring and adjustments of gas composition, making it more complex and expensive.
    • Not feasible for all food products due to the cost and equipment requirements.
  • Food Types
    • Fresh fruits and vegetables (e.g., apples, tomatoes, leafy greens), certain flowers, and some packaged herbs.

Sous Vide Packaging

Sous vide is a cooking method where food is vacuum-sealed in a plastic bag and then cooked in a water bath at a precise, low temperature. This technique ensures even cooking while preserving the food’s flavors, textures, and nutritional value.

  • Advantages
    • Preserves the natural flavors, textures, and nutrients of the food.Reduces the risk of contamination due to the sealed environment.
    • Enhances food safety and shelf life.
  • Disadvantages
    • Requires specialized equipment (e.g., sous vide cookers).
    • The vacuum seal may lead to the growth of anaerobic pathogens if temperature control is not strictly followed.
  • Food Types
    • Meat, poultry, fish, vegetables, eggs, and ready-to-eat meals.

Cook-Chill Packaging

Cook-chill involves cooking food, then rapidly chilling it and vacuum-sealing it in heat-stable bags for extended storage. This method is commonly used for large-scale meal preparation in institutional food service operations.

  • Advantages
    • Extends shelf life by maintaining food at a safe, chilled temperature.Ideal for bulk food preparation, ensuring consistent quality and flavor.
    • Convenient for large-scale foodservice operations.
  • Disadvantages
    • Requires rapid cooling to ensure food safety.
    • Texture and quality may degrade for certain food types after chilling and reheating.
  • Food Types
    • Cooked meats, soups, stews, sauces, and ready-to-eat meals.

Terms related to ROP products

The terms listed below highlight the critical factors involved in ROP, particularly in relation to food safety and quality. Each element is interlinked to ensure that ROP technology prevents microbial growth while maintaining the quality and safety of packaged food.

Aerobic Conditions — The environment contains oxygen. In ROP, the goal is to reduce oxygen levels to prevent the growth of aerobic bacteria. Understanding aerobic conditions is important to ensure that oxygen is adequately removed or replaced in the packaging to prevent spoilage and preserve product quality.

Anaerobic Conditions — The environment does not contain oxygen. ROP technologies (e.g., vacuum packaging) rely on anaerobic conditions to extend shelf life by preventing the growth of aerobic spoilage organisms. However, they also create an environment where anaerobic pathogens, such as C. botulinum, may thrive if not properly controlled.

Vegetative Cells — A state in which bacteria are active and capable of reproduction/ growth, and in particular, bacteria that produce toxins. While reducing oxygen slows down the growth of many microorganisms, vegetative cells can still grow in anaerobic environments if not properly controlled. Pathogens such as C. botulinum can thrive in ROP conditions, making it essential to manage temperature, time, and sanitation to prevent contamination.

Spore-Forming Bacteria — Bacteria capable of forming spores, which are thick-walled formations that protect the bacterial cell against unfavorable or hostile environmental conditions (e.g., high acid, high temperature, drying, freezing).

Spore-forming bacteria, like C. botulinum, are a significant concern in ROP foods. Spores can survive low-oxygen conditions and temperature abuse, and they only become dangerous when they “germinate” into vegetative cells that can produce toxins. ROP packaging must account for controlling temperature and maintaining proper storage to prevent spores from becoming active.

Canning — A food preservation method where food is heat-processed and sealed in an airtight container to prevent spoilage and stored at ambient conditions. Examples include dilly beans, acidified pickles, hot sauces, and BBQ sauces.

Canning and ROP share similar goals of preserving food by controlling oxygen but differ in their techniques. While canning ensures the elimination of oxygen and kills microorganisms through heat, ROP relies on reduced oxygen in combination with refrigeration to preserve products. Both methods must control temperature and time to prevent foodborne pathogens, especially C botulinum, from thriving.

Sanitation Standard Operating Procedure (SSOP) — A documented plan outlining procedures for maintaining sanitary food handling and general hygiene practices. It includes monitoring, corrective actions, and the responsibilities of designated personnel.

ROP foods are highly susceptible to contamination if not handled properly. SSOPs are critical for ensuring that all steps of ROP packaging, including sealing, storage, and transportation, are done hygienically to prevent contamination by harmful microorganisms.

Potentially Hazardous Foods (PHF) / Temperature Controlled for Safety (TCS) — Foods that require temperature control because they support the rapid growth of harmful microorganisms or the production of toxins. These foods require temperature control because they can support:

  • The rapid and progressive growth of infectious or toxigenic microorganisms, or
  • The growth and toxin production of C. botulinum, or
  • In raw shell eggs, the growth of Salmonella Enteritidis.

Many ROP products are classified as PHF/TCS, such as meats and seafood, which require careful control of temperature throughout the packaging and storage processes. Failure to maintain proper temperatures in ROP systems can lead to the growth of pathogens like C. botulinum, which thrive in low-oxygen conditions.

Curing — The process of adding salt, sugar, nitrite, and/or nitrate to meat or poultry for preservation. If you are adding nitrate and/or nitrites, then you are curing. Curing is an essential preservation method that can complement ROP by inhibiting the growth of harmful bacteria. However, when curing meats, especially in vacuum-sealed or MAP packages, care must be taken to balance oxygen levels and avoid creating an environment where harmful pathogens can proliferate. Nitrites also play a role in preventing the growth of C. botulinum in cured meat products.

Food Safety Concerns With Vacuum Packaging or Rop Products

C. botulinum is a dangerous bacterium capable of thriving in anaerobic conditions, such as those found in vacuum packaging and other ROP methods, if proper precautions are not taken. Its ability to form spores allows it to survive adverse conditions. While spores are harmless in their dormant state, improper handling of susceptible products can create conditions that trigger their transformation into vegetative cells, which can grow, reproduce, and produce a deadly neurotoxin. This heat-stable toxin remains potent even after cooking, with minute quantities—measured in nanograms—capable of causing paralysis and death.

C. botulinum spores can remain dormant for years, enduring extreme conditions, including freezing, refrigeration, boiling water (212°F/100°C), drought, high moisture, and aerobic and anaerobic environments. This bacterium is found everywhere and can contaminate any food. That’s why it’s crucial to process, handle, and store food correctly to prevent it from growing and producing toxins.

ROP conditions suppress most spoilage microorganisms, allowing C. botulinum to proliferate undetected if safety measures are not followed. Foods contaminated with botulinum toxin often appear, smell, and taste normal, making detection difficult without laboratory testing. Given these risks, strict food safety protocols are essential to prevent contamination and ensure consumer safety.

Clostridium botulinum Strains and Growth Conditions

Understanding the different strains of C. botulinum is crucial for ensuring food safety in ROP. Specifically, the temperature tolerance variations between strains directly impact the safe handling and storage of ROP products.

  • Type E and non-proteolytic Types B and F: These strains, often associated with fish and fishery products, pose a significant risk because they can grow and produce deadly toxins at temperatures as low as 38°F (3.3°C). This means that standard refrigeration temperatures may not be sufficient to prevent toxin production in these products.
  • Type A and proteolytic Types B and F: While these strains, commonly found in red meat, poultry, pork, vegetables, and other commodities, have a slightly higher minimum growth temperature of 50°F (10°C), they still represent a serious hazard.

Clostridium botulinum Control Measures in Reduced Oxygen Packaging (ROP) Conditions

In retail settings, ROP presents a significant risk of C. botulinum growth. The oxygen-deprived environment created by ROP inhibits competing spoilage microorganisms, allowing C. botulinum to thrive and produce deadly toxins if proper safety measures are not followed. A particularly dangerous characteristic is that contaminated ROP foods may appear, smell, and taste completely normal, making detection extremely difficult without specialized laboratory testing. Given the high mortality rate associated with botulism and the lack of obvious warning signs, the storage and handling of ROP foods in retail environments are strictly regulated.

Retail food establishments must understand that preventing C. botulinum growth requires a multi-barrier approach, often implemented within the framework of a HACCP plan. While HACCP is a standard in food processing, its application in retail settings, particularly for ROP, requires careful attention to specific control points.

To ensure clarity and relevance, it’s essential to understand that the recommended controls for C. botulinum in ROP vary depending on the specific type of food processing. For retail operations, this translates to different handling and storage protocols depending on the type of ROP product being prepared or sold.

Processing and Storage Controls

Heat Treatment

Standard cooking methods like pasteurization or sous vide do not kill C. botulinum spores. Achieving commercial sterility, which does eliminate these spores, is generally not feasible in retail settings. Therefore, heat treatment alone is insufficient for safe ROP. The retail service must implement other critical controls, including:

  • Strict temperature control.
  • pH and water activity control.
  • Proper food handling and rapid cooling.
  • A validated HACCP plan.
  • Accurate labeling

Refrigeration

When heat sterilization is not feasible, strict temperature control is essential to prevent C. botulinum growth:

  • Type E and non-proteolytic Types B and F (commonly found in fish and fishery products) require storage at or below 38°F (3.3°C).
  • Types A and proteolytic Types B and F (commonly found in red meat, poultry, pork, and vegetables) require storage at temperatures below 50°F (10°C).
  • To inhibit most C. botulinum strains, refrigeration should be maintained at or below 41°F (4.4°C).

pH and Water Activity (aw) Controls

  • C. botulinum cannot grow in foods with a pH of 4.6 or lower.
    • Low water activity (aw) also inhibits growth:
      • Type A and proteolytic Types B and F require aw ≤ 0.935.
      • Type E and non-proteolytic Types B and F require aw ≤ 0.97.

Implementing these control measures is critical for ensuring the safety of ROP foods and preventing the risk of botulism.

Additional Control Measures

Oxygen Scavengers

The use of oxygen scavengers in ROP packaging helps limit the available oxygen, reducing the growth of aerobic microorganisms and spoilage bacteria. However, because C. botulinum thrives in low-oxygen environments, oxygen scavengers alone do not control its growth. This is why additional control measures, such as refrigeration below 38°F (3.3°C), low water activity, and preservatives, are necessary to mitigate the risk of botulism in ROP-packaged foods.

Time and Temperature Abuse Prevention

It is crucial to continuously monitor time and temperature to prevent abuse. Temperature monitoring should be maintained throughout the entire process, particularly during transport and storage, to ensure that foods stay within safe temperature ranges and avoid the risk of C. botulinum growth.

Preventing Cross-Contamination

Preventing cross-contamination during processing, packaging, and handling is vital in minimizing the introduction of C. botulinum spores. Proper sanitation practices and staff training are key in reducing contamination risks.

Verification (Check) and Validation (Prove)

To guarantee your ROP safety controls (temperature, pH, water activity) work consistently, you must:

  • Check: Regularly test and calibrate equipment like thermometers and pH meters for accuracy. This includes regular checks and calibration of equipment like temperature sensors and pH meters, as well as microbiological testing to confirm that products meet safety standards
  • Prove (Validate): Show your ROP process consistently makes food safe. This can include:
    • Microbiological testing.
    • Detailed process records.
    • Expert food safety review.

Packaging Integrity and Seal Checks

Ensuring the integrity of ROP packaging is critical. Compromised seals or packages must be identified and corrected to prevent the introduction of oxygen, which can alter the anaerobic conditions and promote C. botulinum growth.

Hazard Analysis Critical Control Point Plan Implementation

All ROP products should be produced and packaged under a comprehensive HACCP plan. This plan identifies potential hazards, establishes critical control points, and outlines monitoring and corrective actions related to temperature, pH, water activity (aw), and packaging integrity.

By incorporating these additional control measures into the existing guidelines, the risk of C. botulinum contamination in ROP products can be significantly reduced.

Regulatory Considerations and Hazard Analysis Critical Control Plan

Due to the high mortality rates associated with botulism and the absence of warning signs when contaminated with C. botulinum toxin, foods held in anaerobic conditions are strictly regulated. To ensure the safety of PHF or TCS foods packed in ROP packages, manufacturers must employ multiple barriers to prevent the growth of C. botulinum. These products must be produced and packed under a comprehensive HACCP plan, which includes monitoring, preventive actions, and appropriate corrective measures to maintain food safety.

Reduced Oxygen Packaging Hazard Analysis and Critical Control Point Plans

HACCP is a systematic approach to food safety management that focuses on identifying, evaluating, and controlling biological, chemical, and physical hazards throughout the food production and handling process. From raw material procurement and processing to distribution and consumption, HACCP ensures the safety of food products. For ROP products, implementing an effective HACCP plan is critical to managing the unique risks associated with reduced oxygen environments. Furthermore, in many jurisdictions, a properly implemented HACCP plan is not only best practice but also a legal requirement for the retail sales of ROP products. 

HACCP was first developed in the 1960s by the Pillsbury Company, NASA, and the U.S. Army Natick Research Center to ensure the safety of food for astronauts during space missions. Since the mid-1990s, HACCP has become the foundation of food safety systems across various commodities in the United States and internationally, including those handling ROP products. In Maine, food service establishments producing ROP foods are required to develop and implement a HACCP plan tailored to their specific operations, as mandated by state and federal regulations.

The HACCP system is built upon seven key principles:

  1. Conduct a Hazard Analysis (HA): Identify potential food safety hazards and determine the steps where they are likely to occur in the process.
  2. Identify the Critical Control Points (CCPs): Pinpoint stages where control is essential to prevent or eliminate hazards or reduce them to acceptable levels.
  3. Establish Critical Limits (CLs): Define measurable parameters, such as time, temperature, pH, or water activity, that must be achieved at each CCP to ensure safety.
  4. Monitor CCPs: Implement procedures to monitor CCPs and ensure that critical limits are consistently met.
  5. Establish Corrective Actions (CA): Develop steps to take when monitoring indicates that a critical limit has not been met, including actions to ensure the safety of the product.
  6. Verification: Validate that the HACCP plan is functioning as intended and that all monitoring and corrective actions are effective.
  7. Recordkeeping: Maintain detailed records to document the implementation and effectiveness of the HACCP system, including hazard analyses, CCP monitoring, and corrective actions.

Regulations (2013 Maine Food Code)

The 2013 Maine Food Code outlines specific requirements for ROP to ensure food safety. These regulations are primarily detailed in Sections 3-502.11 and 3-502.12. Sections 3-502.12 and 8-201.14 of the 2013 Maine Food Code outline additional requirements for Reduced Oxygen Packaging (ROP) plans, including HACCP plans for products such as Sous Vide, Cook-Chill, and Cheese Products. It’s essential to note that, although the 2013 Maine Food Code serves as the foundational document, updates and policy changes have been implemented, which may impact these sections. For instance, the “Maine HIP HACCP Variance Guidance and Resources” document, published in December 2024, references updated allowances due to newer versions of the FDA Food Code.

Section 3-502.11 — Variance Requirement

Any potentially hazardous food products that do not meet the criteria listed in 3.502.12 will require a Variance and a HACCP plan. This section mandates that a food establishment must obtain a variance from the regulatory authority before engaging in certain specialized processing methods, including:

  • Smoking food as a method of preservation rather than flavor enhancement.
  • Curing food.
  • Using food additives or adding components like vinegar for preservation or to render a food non-potentially hazardous (non-Time/Temperature Control for Safety).
  • Packaging food using an ROP method, except where specific controls for C. botulinum and L. monocytogenes are implemented as specified under §3-502.12.
  • Operating a molluscan shellfish life-support system display tank used to store or display shellfish offered for human consumption.
  • Custom processing animals for personal use as food and not for sale or service in a food establishment.
  • Preparing food by another method determined by the regulatory authority to require a variance.
  • Sprouting seeds or beans.

To initiate a variance in Maine, contact the Maine Department of Health and Human Services (DHHS), Health Inspection Program. Visit their website or contact them directly for application details and required documentation. Be prepared to provide a comprehensive HACCP plan and detailed information about your specialized processing methods. Early communication with the DHHS is crucial for a smooth process.

Section 3-502.11

For PHF products that do not meet the criteria in Section 3-502.12, a variance and HACCP plan are required. These products will require additional monitoring, depending on the secondary barrier used. A food processing authority must evaluate the adequacy of the secondary barrier.

Examples of Products Requiring Variance and Hazard Analysis Critical Control Plans:

  • Unfrozen processed fish and smoked fish packed by ROP.
  • Soft cheeses like ricotta, cottage cheese, and cheese mixed with meats, vegetables, or fish.
  • Smoked meats, cured meats, and poultry cured on-site.

Guidance for Hazard Analysis Critical Control Plans Requiring Variances

  • Develop a HACCP Plan (additional information is available on the FDA website).
  • The licensee can either write the HACCP plan themselves or consult a recognized HACCP consultant.
  • If the product is sold at retail, the variance must be approved by either the Department of Health and Human Services (DHHS) or the Department of Agriculture, Conservation, and Forestry (DACF), depending on which agency holds the license. For inquiries, contact: DHHS: 207.287.5671 | DACF: 207.287.3841.
  • For wholesale, the variance must be approved by the Department of Agriculture, Conservation, and Forestry (DACF): 207.287.3841.

Section 3-502.12 — Reduced Oxygen Packaging, Criteria

Any PHF products that are allowed to be packed under ROP Without a Variance must meet the criteria in 3-502.12 (low aw, low pH, USDA cured, raw meat, raw poultry, and/or raw vegetables). This section outlines the HAACP plan and control requirements for ROP storage of specific products such assous vide, cook-chill, and cheese products.

Potentially Hazardous Foods that meet the following criteria: Low aw, low pH, USDA-cured, raw meat, raw poultry, raw vegetables.

Requirements for Products Meeting Criteria (No Variance Required):

  • Barrier to prevent C. botulinum growth.
  • Strict temperature control to ensure safety.
  • Shelf life of 7 days if stored under proper refrigeration.
  • If packaged on-site at an eating establishment, a HACCP plan and recordkeeping are required.

This section specifies that, unless a variance is obtained as per §3-502.11, a food establishment packaging PHF (Time/Temperature Control for Safety Food) using a ROP method must control the growth and toxin formation of C. botulinum and the growth of L. monocytogenes.

Key requirements include:

  • Maintaining the packaged food at 5°C (41°F) or less and meeting at least one of the following criteria:
    • aw of 0.91 or less.
    • pH of 4.6 or less.
    • USDA-cured meat/poultry in intact packaging
    • Raw meat, poultry, or vegetables with high levels of competing organisms
  • Packages must be clearly labeled to:
    • Keep at ≤ 41°F
    • Discard within 30 days if not consumed or sold
  • Shelf life is ≤ 30 days at ≤ 41°F, unless frozen or per the manufacturer’s date
  • No ROP for fresh fish, unless frozen before, during, and after packaging
  • HACCP plan must include:
    • Operational procedures to prevent cross-contamination
    • Cleaning and sanitization protocols
    • Staff training requirements
  • Cook-Chill & Sous Vide Requirements:
    • Food must be consumed on-site or within the same business (no resale).
    • Cooling and storage must follow strict temperature/time controls:
    • Held ≤ 41°F for 7 days maximum
    • Lower temperature storage allows longer hold times
    • Continuous electronic monitoring of time and temperature is required
    • Records must be maintained for at least 6 months
  • ROP for Cheese:
    • Only commercially manufactured hard, pasteurized process, or semisoft cheeses
    • Must be sold or consumed within 30 days or per the manufacturer’s date
    • Requires HACCP plan and clear “use by” labeling
    • High levels of competing organisms.
  • Implementing a HACCP plan that:
    • Identifies the food to be packaged.
    • Describes how the package shall be prominently labeled on the principal display panel with instructions to maintain the food at 5°C (41°F) or below.
    • Includes procedures for maintaining the food at 5°C (41°F) or below.
    • Describes how the operator shall verify that the cooling and cold holding temperature is monitored and documented.

Food establishments must stay informed about any updates or policy changes related to these sections. The Maine Health Inspection Program’s HACCP & Variance Guidance and Resources provides detailed guidance on these requirements. To access this information, visit the Maine Department of Health and Human Services (DHHS) website, specifically the section related to the Health Inspection Program. You can also contact the Health Inspection Program directly for personalized assistance and to obtain specific guidance documents or application forms related to variances. They can provide the most current information and ensure you meet all regulatory standards.

Given that regulations can evolve, it’s advisable to consult the most recent versions of the Maine Food Code and related guidelines to ensure compliance with current standards.

According to the 2013 Maine Food Code, the requirements for Reduced Oxygen Packaging (ROP) are as follows: Products that meet specific criteria to allow ROP without a variance must have a barrier to prevent C. botulinum growth and toxin formation. Strict temperature control provides the second barrier.

If Packaged on Site:

  • A HACCP plan and recordkeeping are required.
  • For most ROP foods (without a variance), a shelf life of up to 30 days is allowed at 5°C (41°F) or lower.
  • For cook-chill and sous vide products, the shelf life is limited to 7 days at 5°C (41°F) or lower.

Although the 2013 Maine Food Code does not reflect these changes, the updated standards have been administratively adopted. Refer to the latest version of the FDA Food Code or the state guidance document for the most recent criteria.

Hazard Analysis Critical Control Plan and Critical Control Points Requirements for Reduced Oxygen Packaging Products

If Held at Refrigerated Temperatures (41°F or lower):

  • Continuous temperature monitoring to ensure the product is stored at or below 41°F (5°C).
  • Written processing procedures, SSOP, and ongoing records are required to show that the product is not temperature-abused during processing and vacuum packing.
  • Labeling: The product must be labeled with “Important — Must be kept refrigerated at 41°F (5°C) or below” and date coding for a shelf life of 7 days.

If Frozen:

  • Written processing procedures, SSOP, and ongoing records to demonstrate that the product is not temperature abused during processing and vacuum packing.
  • Labeling: Must include “Important — Must be kept frozen,” or “Important, keep frozen until used, thaw under refrigeration immediately before use,” or “Important, keep frozen until used, break seal before thawing.”
  • Once removed from the freezer to thaw, the product must have date coding for a shelf life of 7 days.

Written Thawing Procedures:

  • Break the seal before thawing, or
  • Thaw the ROP product under continuous monitoring.

Best Practices (not required but preferred):

  • Continuous monitoring is necessary for cook-chill and sous-vide packaging.
  • Periodic temperature records (e.g., record the temperature of the cooler every 4 hours).

Fish and Seafood Products:

  • Fish and seafood products may not be vacuum packaged at retail unless the fish is frozen before, during, and after packaging. This process still requires a HACCP plan.

These measures ensure that products packed under ROP conditions are safe, with temperature control and labeling providing critical barriers against microbial growth, including C. botulinum.

3-201.12: Food in a Hermetically Sealed Container (“Canning”): Code of Federal Regulations, Title 21, Parts 114 — Acidified Foods.

Acidified Foods: Acidified foods are products that have been acidified through the addition of acids (such as vinegar, citric acid, or lemon juice) to lower their pH to less than 4.6. These foods are typically hermetically sealed to prevent contamination.

Examples of acidified foods include:

  • Pickles
  • Dilly beans
  • Jams and jellies
  • Salsas

Low-Acid Foods: These products (e.g., meats, poultry, seafood, vegetables, dairy) cannot be canned using pressure or water bath canning unless they are acidified to a pH level of 4.6 or lower.

Minimal Hazard Analysis Critical Control Plan Requirements for Acidified Canned Products

  • Submit each product in final packaging for the Product and Process Review Testing. Contact the Maine Department of Health and Human Services (DHHS) Health and Environmental Testing Laboratory (HETL) for microbiological testing. The University of Maine Food Testing Services may also offer relevant analyses. Additionally, utilize certified private laboratories in the region. Consult with food safety experts to determine the appropriate testing methods and interpret the results. Ensure any chosen laboratory is accredited and maintain detailed testing records
  • Follow all recommendations for process time, temperatures, critical limits/factors, procedures, calibration records, and batch pH records as outlined in the Product and Process Review Testing Letter of approval.

Summary: Safe Reduced Oxygen Packaging Product Production in Food Service

If you produce a potentially hazardous ROP food that meets the following criteria:

Low aw, low pH, USDA-cured, raw meat, raw poultry, raw vegetables:

  • Develop a HACCP plan.
  • Submit the HACCP plan to DHHS Health Inspection Program or DACF if required.

Contact: Key Bank Plaza, 3rd Floor, 11 SHS, Augusta, Maine 04333-0011, 207.287.5671.

Fish and seafood products must be frozen before, during, and after packaging at retail.  A HACCP plan is required.

If your ROP food does not meet these criteria:

  • Develop a HACCP plan.
  • Submit a variance to a processing authority for evaluation.
  • Submit the HACCP plan and variance to DHHS/DACF for review.

For acidified canned foods:

  • Submit each product for Product and Process Review Testing.
  • Follow all recommendations in the Product and Process Review Testing Letter of approval.
  • Submit a HACCP plan and variance request to DHHS/DACF for review.

Contact Information

University of Maine Cooperative Extension

  • Sanitation (General Industry): Contact Theresa Tilton at tilton@maine.edu, 207.942.7396.
  • Dairy Sanitation: Contact Melissa Libby at libby1@maine.edu, 207.581.2788.
  • Hazard Analysis Critical Control Point (HACCP) Certification: Gulsun A. Evrendilek at gulsun.akdemir@maine.edu, 207-581 1378.
  • Meat, Poultry, and Seafood: Contact Theresa Tilton at tilton@maine.edu, 207.942.7396.

References

Department of Agriculture. 2025. Reduced oxygen packaging (ROP).  mda.state.mn.us/food-feed/reduced-oxygen-packaging-rop

Division of Environmental and Community Health Maine Center for Disease Control & Prevention. 2025. Maine Food Code Specialized Processing Methods. maine.gov/dhhs/mecdc/environmental-health/el/site-files/Maine%20HIP%20HACCP%20Variance%20Guidance%20and%20Resources.pdf

Eilert, S.J., 2005. New packaging technologies for the 21st century. Meat Science, 71(1), pp.122-127. https://doi.org/10.1016/j.meatsci.2005.04.003

Glass, K.A., Golden, M.C., Wanless, B.J., Conklin, T., Schweihofer, J.P. and Schill, K.M., 2024. Inhibition of Listeria monocytogenes and Clostridium botulinum in uncured shredded pork and turkey packaged under reduced oxygen conditions. Journal of Food Protection, 87(6), p.100271(https://doi.org/10.1016/j.jfp.2024.100271

Kandeepan, G. and Tahseen, A., 2022. Modified atmosphere packaging (map) of meat and meat products: A review. Journal of Packaging Technology and Research, 6(3), pp.137-148. doi.org/10.1007/s41783-022-00139-2

Munir, M.T., Mtimet, N., Guillier, L., Meurens, F., Fravalo, P., Federighi, M. and Kooh, P., 2023. Physical treatments to control Clostridium botulinum hazards in food. Foods, 12(8), p.1580. https://doi.org/10.3390/foods12081580

New York State Department of Health. 2025   health.ny.gov/environmental/indoors/food_safety/pubs/rop_guidance.pdf

Nwadike, L. 2023.Vacuum and Reduced Oxygen Packaging. Kansas State University/University of Missouri Extension. extension.missouri.edu/media/wysiwyg/Extensiondata/Pub/pdf/hesguide/foodnut/n03639.pdf

UVM Extension Fact Sheet. 2013. Reduced oxygen packaging- including vacuum packaging.

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