Implementing Microbial Control Interventions on Beef and Veal in Provincially Licensed Plants

Meat Inspection Program: Food Inspection Branch Infosheet - April 2018

Table of Contents

  1. Introduction
  2. Contamination Risks
  3. What is a Microbial Control Intervention?
  4. Lactic Acid, Acetic Acid or other Organic Acid Rinses
  5. Hot Water Rinse or Steam
  6. Dry Aging
  7. Appendix

Introduction

Escherichia coli (E. coli) bacteria normally live in human and animal intestines. Most E. coli are harmless and are an important part of a healthy human intestinal function. However, some E. coli are pathogenic, meaning they can cause illness.

Pathogenic E. coli cause disease by making a toxin called Shiga toxin. The type of E. coli that make these toxins are called "Shiga toxin-producing" E. coli, or STEC for short. STEC cause human illnesses, which can range from mild diarrhea to very severe and life-threatening conditions, including death.

The STEC strain most frequently associated with human illness in North America is serotype O157:H7. However, several other E. coli serotypes (O26, O45, O111, O103, O121, and O145) are also commonly associated with severe illness in humans.

Contamination Risks

Contamination of meat during slaughter and processing is a major risk for subsequent food-borne illnesses in humans. This is because bacteria are often transferred from the fecal material, gastrointestinal tract, hide and plant equipment to the carcass during processing.

This contamination is very difficult to prevent. There is no substitute for keeping bacteria off the carcass in the first place; however, microbial carcass interventions can be used to further reduce the presence of E. coli on the carcass.

What is a Microbial Control Intervention?

Microbial control interventions are biological or chemical processes or agents, usually applied to the surface of the meat, to adequately inhibit, reduce or kill micro-organisms.

Applying microbial control interventions to carcasses during and/or after the dressing procedure is important to effectively remove or inactivate bacterial contamination and improve meat safety.

Commonly used microbial control interventions include:

  • organic acid rinses
  • hot water rinses
  • steam pasteurization
  • steam vacuuming
  • dry aging

See the Appendix for a list of microbial control interventions and implementation guidelines.

Best Practices

  • Choose the most appropriate microbial control intervention for your operation that will reduce the presence of contaminating E. coli. The type of microbial control intervention you choose will depend on the effect of the intervention, the ease of use, the cost, and the physical effect on the meat product.
  • Make sure that carcasses are as clean as possible using good slaughter practices and proper carcass washing before the intervention application.
  • Apply microbial interventions after the final carcass wash because this is the last step during processing before chilling. Trimming removes visible contamination, whereas microbial control interventions are effective in removing bacterial contamination that may not be visible.

Lactic Acid, Acetic Acid or other Organic Acid Rinses

Lactic acid is most effective when it is mixed and applied at up to 5.0 per cent, with warm water (up to 54.5°C / 130°F). The most common applied level of lactic acid on carcasses being marketed whole is 2.5 per cent, with no rinse required.

Acetic acid is most effective when it is mixed and applied at up to 2.5 per cent, with a warm solution temperature (up to 54.5°C / 130°F).

Citric acid is most effective when it is mixed and applied at up to 2.5 per cent, with warm water (up to 54.5°C / 130°F). No rinse is required.

Best Practices

  • Regardless of the acid used, two thorough passes should be made over the entire carcass surface with a hose or garden type sprayer approved for use in a food establishment.
  • Use a warm (preferable), thorough carcass wash before applying any acid wash. Allow the carcass to drip for a full five minutes so that any acid intervention applied to the carcass is not diluted.
  • Document the proper concentration of the solution when it is made and when the acid intervention is applied to the carcasses. Titration kits, available from your chemical supplier, are also necessary to test the concentration of the acid solution to ensure it is meeting requirements.
  • Wear proper personal protective equipment (PPE) when mixing and spraying chemicals.
  • Ensure Safety Data Sheets are accessible to all workers.
  • Application of chemicals to bovine carcasses must follow manufacturer's requirements.

Hot Water Rinse or Steam

Hot water spray or hot water wash cabinet must apply water at 74°C (165°F) to the surface of the carcass for a minimum of five seconds.

Steam pasteurization using a cabinet or steam vacuuming for spot treatment is also acceptable provided the water is 82-94°C (180-201°F).

Best Practices

  • A minimum of two thorough passes should be made over the entire carcass surface with the hot water or steam.
  • The health and safety of your workers is crucial when applying water or steam at these temperatures. Ensure that workers are kept at a safe distance from hot water/steam on the kill floor.
  • Take multiple temperature readings of the water throughout the day to ensure that minimum temperatures are being reached.
  • Keep records of water/steam temperatures, and how and when the microbial control intervention is applied to the carcass to ensure effective implementation of interventions.

Dry Aging

Dry aging is an effective microbial control intervention when carcasses are kept in a cooler that is less than 4°C in temperature and less than 90 per cent relative humidity for at least six days.

Best Practices

  • Be prepared to verify that the conditions in your cooler do, in fact, achieve the desired effect of reducing STEC.
  • Carcass chilling should focus on the carcass surface temperature because this is where the pathogen contamination is most likely.
  • To prevent cross-contamination and allow efficient air circulation, cooler storage rails must be placed far enough from refrigeration equipment, walls, columns and other fixed parts. Sides of beef should be placed in the chiller so that there is no contact between them for efficient air circulation.
  • In order to minimize condensation, plants should explore options for rotating the filling of the hot boxes, carcass spacing and increasing air flow.
  • Walkways should be cleaned on a routine frequency to prevent contaminants from the floor and wall from splashing onto the carcass.
  • Record cooler temperatures and relative humidity to make sure the microbial control intervention is effective. A temperature data logger and hygrometer are useful tools to take these readings.

Appendix

Microbial Control Intervention Implementation Guidance Suggested Record Keeping
Hot water Minimum 74°C (165°F) for 5 seconds (1) Periodic check of water temperature, and (2) documentation of application to carcass
Hot water wash cabinet As per manufacturer's instructions, water temperature minimum 74°C (165°F) for 5 seconds (1) Periodic check of water temperature, and (2) documentation of application to carcass
Steam pasteurization As per manufacturer's instructions (1) Periodic check of water temperature, and (2) documentation of application to carcass
Steam vacuuming As per manufacturer's instructions; Steam is delivered by a continuous stream of 7-10 psi water at 82-94°C while simultaneously vacuuming the area around the stream of hot water (1) Periodic check of water temperature, and (2) documentation of application to carcass
Peroxyacetic acid Not greater than 220 ppm (1) documenting proper concentration of solution at make-up, and (2) documentation of application to carcass
Acetic acid 2.5% applied with warm water (up to 54.5°C / 130°F) (1) documenting proper concentration of solution at make-up, and (2) documentation of application to carcass
Lactic acid 5% applied with warm water (up to 54.5°C / 130°F) (1) documenting proper concentration of solution at make-up, and (2) documentation of application to carcass
Citric acid 2.5% applied with warm water (up to 54.5°C / 130°F) (1) documenting proper concentration of solution at make-up, and (2) documentation of application to carcass
Sodium hypochlorite Not greater than 20 ppm, followed by a potable water rinse (1) documenting proper concentration of solution at make-up, and (2) documentation of application to carcass
Dry aging No more than 90% relative humidity, temperature of 4°C or less for at least 6 days (1) cooler temperature less than 4°C, (2) relative humidity is maintained at less than 90% and (3) documentation that carcasses are chilled/aged for at least 6 days
** Any other microbial control intervention that is effective in reducing carcass microbial loads. Scientifically validated by the operator and submitted for review and approval by the Food Inspection Branch

 


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Author: OMAFRA Staff
Creation Date: 09 May 2018
Last Reviewed: 09 May 2018