M-I-03-2: Biosecurity Guidance for the Food and Drug Administration's (FDA) Regional Milk Specialists (RMS's), Milk Safety Branch (MSB) and State Training Team (STT) Staff when Visiting Dairy Farms

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March 19, 2003

TO: All Regional Food and Drug Directors
Attn: Regional Milk Specialists

FROM: Milk Safety Branch (HFS-626)

SUBJECT: Biosecurity Guidance for the Food and Drug Administration's (FDA) Regional Milk Specialists (RMS's), Milk Safety Branch (MSB) and State Training Team (STT) Staff when Visiting Dairy Farms

This memorandum provides FDA's guidance when visiting any type of facility where dairy animals are housed. The controls and procedures are intended to prevent a person from becoming a vector or carrier of animal diseases, to prevent the spread of animal disease, and to set a good example for dairy producers, industry servicemen, veterinarians and others who routinely visit dairy farms.

This memorandum is based on guidance from FDA's Inspector's Operation Manual (IOM) and the United States Department of Agriculture's (USDA) Guidelines for Biosecurity for On-Farm Visits.


The outbreak and spread of foot and mouth disease in the UK has raised the levels of awareness regarding the prevention and control of animal diseases in the United States. Foot and mouth disease does not currently exist in the USA. However, other animal diseases are present in the United States that can be spread from farm-to-farm such as Johne's disease, Salmonella, and Bovine Viral Diarrhea. Farmers, livestock, and crop producers are paying more attention to the prevention of disease introduction and transmission on their farms due to concerns of potential profit loss and decreased marketability. Biosecurity refers to the control measures implemented at a producer firm/facility to prevent the introduction and transmission of disease. FDA personnel should follow any biosecurity practices that are already in place by the firm visited or by the State's animal health agency, if those practices are more comprehensive than the guidance included in this Memorandum of Information (M-I).

Personal Protective Equipment and Biosecurity Precautions

The necessity for personal protective equipment and the extent of biosecurity precautions vary greatly depending on the types of operations and sites visited, and the types of diseases and pathogens encountered at a site.

Minimum Biosecurity Measures

  • Avoid livestock areas, pens, barns, etc., unless it is necessary to complete the goal of the visit.
  • Park the vehicle in a location to avoid contact with manure or other organic material. Avoid driving through manure or wastewater if possible. If the vehicle becomes grossly contaminated with organic material, the vehicle should be washed before any other sites are visited.
  • Wash your hands with soap and water or an antibacterial gel upon entering the premises.

Biosecurity Levels

Routine levels of biosecurity measures are described below. When in doubt as to which level of biosecurity is needed, choose the higher level. These steps should be repeated for each facility that is visited. Extra clothing, coveralls, and footwear should be accessible in case your clothing becomes contaminated during the inspection process. If your clothing has become contaminated by contact with animals or their waste and you cannot decontaminate the items contaminated, the inspections for that day should be terminated until the situation is corrected.

Level 1 - No Contact Sites: Visits to producer firms that entail office or home visits only. No contact with livestock or their housing area(s) (including pet animals). These are sites that can reasonably be expected not to produce contamination of footwear or contamination of clothing.

  • Apply the minimum measures outlined above under the "Minimum Biosecurity Measures".

Level 2 - Minimal Contact Sites: Visits to producer firms where minimal contact with livestock or their housing area(s) is unavoidable to attain the goal of the visit. Contact constitutes walking through animal housing, dairy production areas or pastures where the animals are not within reach. These are sites that can reasonably be expected to produce contamination of footwear, but not to produce contamination of clothing. (Examples would be sampling surveillance certification, inspections of milk houses, milk parlors, cattle housing areas, pasture areas and holding lots while the animals are either not present or are not in close proximity).

  • Apply the "Minimum Biosecurity Measures" plus
  • Immediately put on clean rubber boots or disposable plastic boot/shoe covers upon exiting the vehicle.
  • After returning to the vehicle, clean and disinfect any equipment that may have become contaminated, with a brush and approved EPA disinfectant solution. (See listed supplies)
  • Clean rubber boots with an approved EPA disinfectant diluted with water. Scrub the bottoms of the boots with a brush to remove all dirt or debris. Properly dispose of the disinfectant in a manner consistent with its label.
  • If wearing plastic disposable boot/shoe covers, remove them and place them in a designated plastic bag. This bag should be left on the premises for disposal by the owner/producer or placed in a designated "dirty" area of the vehicle.

Level 3 - Close Contact Sites: Visits to producer firms where there will be close contact with livestock to attain the goal of the visit. These are sites that can reasonably be expected to produce contamination of your footwear and clothing. (Examples would be inspections of milk parlors, cattle housing areas, pasture areas and holding lots while the animals are present and in close proximity).

  • Apply the "Level 2" biosecurity measures; plus
  • Put on clean coveralls immediately upon exiting the vehicle.
  • After returning to the vehicle, remove coveralls so that they are inside out and place in a designated plastic bag. If using disposable coveralls, dispose of in the same manner as disposable boot/shoe covers.
  • Launder all cloth coveralls prior to the next usage.

Cleaning and Disinfecting


No disinfectant can work effectively in the presence of organic material. "Organic material" means manure, urine, blood, pus, milk, plant material, soil, saliva, or any other animal/plant contaminant. It is therefore imperative that all surfaces are cleaned thoroughly prior to immersion in an appropriate disinfection solution. Always scrub the bottoms and sides of boots. Dirt, debris, and organic matter must be removed from all supplies, equipment, and vehicles. All cloth clothing (coveralls, hats, jackets, gloves, etc.) must be laundered, preferably with hot water or a disinfectant soap prior to wearing at another site.


Disinfecting solution should be prepared with several things in mind. Among them:

  • Suitability of the product for the organisms you are trying to kill.
  • Proper dilution of the disinfectant to provide efficacy.
  • Contact time necessary to completely disinfect.
  • Usage of the disinfectant consistent with its label.
  • Disposal of the disinfectant consistent with its label.

All contaminated items used at a site must be disinfected after cleaning. If the disinfectant solution becomes contaminated with debris or organic matter, it must be discarded and replaced with new solution. Avoid splashing exposed skin with solution, as it may be irritating. Prepare and use disinfectant solution close to the vehicle so you do not become re-exposed to contaminants after disinfection. Allowing boots and equipment to dry completely after disinfection will reduce the survival of many disease-causing organisms.


Purchase commercially available solutions for disinfecting objects or consult with your servicing laboratory. Commercial products such as Nolvosan, Efersan, One Stroke Environ or Virkon-S may be used as long as they are registered by EPA for the intended purpose. Lye or chlorine based cleaners and disinfectants may also be used.
The following formula for household bleach may be used. Mix 3/4 cup (6 oz) of liquid bleach (5.25%) in one gallon of water (128 oz.). This solution will be approximately 1:20 dilution. Formulations of household bleach, which are more concentrated than 5.25%, are commercially available. Dilute accordingly to these directions. A more concentrated 1:10 solution (1-oz. bleach to 9-oz. water) may be used with decreased contact time required. Dilutions should be prepared fresh daily and protected from light.
You should read the label and be familiar with directions and precautions, such as removing any organic matter from objects to be disinfected, for any disinfectant you use. In the absence of directions or for chlorine solutions you prepare:

  • Remove visible dirt from the object (boots, tools, tires, etc.).
  • Wipe, brush or scrub surfaces with the solution and keep wet for 2 minutes.
  • Allow to air dry or dry with previously sterilized toweling.


Depending on the type of animal contact anticipated, the following supplies should be carried in the vehicle in preparation for site visits:

  • Rubber or plastic disposable boots (many pairs)
  • Disinfectant (bleach or other accepted disinfectant)
  • Long handled brush, other brushes as needed for cleaning
  • Rubber or plastic container to wash rubber boots in and to collect disinfectant solution
  • Disposable or washable outerwear (coveralls, jackets, hats, gloves, etc.)
  • Trash bags
  • Large plastic containers (may be used in lieu of trash bags to store clean/dirty clothes and items in separate areas)

Copies of this memorandum are enclosed for distribution to Regional Milk Specialists, State Milk Regulatory Agencies, State Veterinary Boards/Associations and State Milk Sanitation Rating Officers in your region. This memorandum will also be available on the FDA Web site at (Updated Web Address) at a later date and should be widely distributed to representatives of the dairy industry and other interested parties.

CAPT Robert F. Hennes, RS, MPH
Chief, Milk Safety Branch

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