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FOOD CONTAMINATION AND DECONTAMINATION

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APPENDIX F - continued from previous page

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(f)   Painted, varnished, and waxed surfaces are generally smooth and nonporous. Dust and liquids are readily removed by wiping, brushing, or vacuuming. Absorbed materials are removed by hot water, detergent, or complexing agents. None of these surfaces stand up well to heavy abrasive techniques. Agents can be attacked and removed by caustics, acids, and organic chemicals. Some of these surfaces readily absorb agents, so weathering following decontamination is advisable.

(g)   Rubber is a porous material that can absorb agents. It is not easily decontaminated by abrasive techniques. Warm, soapy water used with brushing is effective since it removes some absorbed contamination. Strong acids, alkalies, and organic solvents may deteriorate and decompose rubber articles.

(7)   Operational rations are the primary rations issued; always issue uncontaminated stocks first. This allows for decontamination of contaminated stocks without interrupting supply support. Normally, contaminated stocks are not issued. The decision to issue contaminated items is based on the tactical situation, criticality of the items, type and extent of contamination, and the time and resources available for decontamination. Decontamination efforts on subsistence items are limited to the containers and carton overwrap material.

(a)   The MRE retort and nonretort food pouch may be decontaminated with soap and water wash. The chemical agents will be removed by the solutions.

(b)   Semipermeable materials (polyethylene menu bag, shrink wrap, and film wrap) may have chemicals deposited not only on the surface, but also dissolved into the matrix of the material. The chemicals can be removed from the surface by washing with hot soapy water, but contaminant dissolved in the material is not removed. The remaining agent can only be removed by weathering which can be accelerated through the use of heat and sweeping the surface with air.

(c)   Fiberboard is both sorbent and permeable and acts like a blotter. Liquid decontaminants can force the contaminant further into the fiberboard. Any attempt to decontaminate fiberboard would be futile. The only alternatives are to remove the fiberboard, or to allow it to weather.

(d)   Palletized unit loads of MRE outerwraps can be decontaminated through the aid of a forced clean air sweep in 4 to 5 days, compared to 3 weeks or more under natural conditions without a forced air sweep.

(8)   Contaminated food supplies are only handled by personnel trained in decontamination methods and in MOPP Level 4. Contaminated food items are divided into three groups as described below (see Table F-1 for additional information).

(a)   Group I consists of canned and unopened packaged items which have been exposed only to agent vapors. Most items in this group will be safe to issue after a brief period of outdoor airing to remove clinging vapors. Table F-7 lists the decontamination procedures for packaging materials contaminated with nerve agents, mustards, and arsenicals.

Table F-7. Chemical Decontamination of Packaged Material

PACKAGING MATERIAL	CONTAMINATION	DECONTAMINATION PROCEDURES
Airtight metal containers, glass bottles, foil aluminated laminated materials.	Vapor and Liquid	Air for 24 hours. Wash with hot soapy water, soda, or bleach solution. Rinse with water.
Polyester, PVF, wooden boxes, crates, board, multilayer bags.	Vapor	Remove contaminated package. Air contents for 24 hours.
Cardboard, polyethylene.	Liquid	Contaminated contents � treat as unpackaged food.

(b)   Group II consists of canned and unopened packaged items which have been contaminated with a liquid chemical agent.

1.   Attempts to decontaminate porous packaging materials, such as cardboard or wood, are likely to be unsuccessful and may result in spreading the contamination. The best procedure in handling such items is to strip off the outer contaminated coverings and examine the inner layer to see if penetration of the agent has occurred. If it has, continue stripping off layers until an uncontaminated layer is reached and place it in Group I. If the agent has penetrated to the food, place it in Group III.

2.   Food in cans or in other sealed, impermeable containers is not in danger of chemical contamination. Because contamination is confined to the outer surface of the sealed container, decontamination is accomplished by: immersion in boiling, soapy water for 30 minutes and rinse; immersion in boiling water for 30 minutes; spray with DS2; or to wash in hot soapy water, rinse, and aerate. Under no conditions should contaminated containers be opened before they have been decontaminated and monitored.

3.   Supertropical bleach and DS2 can be used on the polyethylene menu bag for up to 24 hours without a significant change in appearance, tensile properties, and size of the plastic. The use of DS2 will cause significant degradative changes to most other plastics, while STB will cause little or no change. Also, DS2 may cause false positive readings when using M8 or M9 paper, or the M256 Detector Kit to check completeness of decontamination.

(c)   Group III will consist of unpackaged or poorly packaged items which have been exposed to an agent in either vapor or liquid form. Foodstuffs in this group should be decontaminated only when absolutely necessary. The decision to use foods that have been contaminated is to be made by the commander. Decontamination procedure to be followed, in order, is: trim surface fat and grossly contaminated areas; wash with water or 2-percent sodium bicarbonate solution; then boil in water.

1.   Boiling in water may be eliminated when the contamination has been only with the vapors of irritant agents. When such an exposure has been light, aeration for a short time may be used for decontamination.

2.   Frying, roasting, or broiling will not remove traces of blister agents from meats. In general, salvage of foods heavily contaminated with droplets of the blister agents, especially the arsenical blister agents, is not practical. Foods of high water or fat content are unfit for consumption and reclamation is not practical when contaminated with liquid mustard or a liquid nitrogen mustard.

3.   When foods have been exposed to blister agent vapor, they can be reclaimed by washing with sodium bicarbonate solutions and rinsing with clear water, by intensive cooking, or in the case of dry provisions, by 24 to 48 hours of aeration. Lean meat contaminated with mustard vapor can be reclaimed by boiling in water for 30 minutes or more. With nitrogen mustard vapor contamination, the meat should be boiled in a 2-percent sodium bicarbonate solution. Discard the water used to boil the meat.

4.   Nerve agent contamination is treated the same as blister agent contamination.

5.   Food such as potatoes and hard-skinned fruits and vegetables can be decontaminated by washing or scrubbing, followed by peeling or scraping, then washing again.

6.   Prepared food in open containers will be contaminated; it must be temporarily isolated, or disposed of (bury or as directed by commander).

7.   A food item that is contaminated with irritants can be decontaminated by airing. Consumability is determined by taste rather than toxicity.

8.   Phosgene is rapidly hydrolyzed, therefore, washing the food with water or airing it will usually suffice.

9.   Food contaminated with white phosphorous should be destroyed.

10.   Normally, hydrocyanic acid will have little effect on food supplies. The exposures will most likely be as a vapor. However, foods with a high water content may become unfit for consumption after exposure to high concentrations.

11.   The effect of CK on foods is not known. Foods exposed to CK vapors are considered toxic.

12.   Table F-8 lists the decontamination procedures for unpackaged food contaminated with a chemical agent.

(9)   Decontaminating cattle, poultry, and other livestock is only attempted when other sources of food are not available. Heavily contaminated animals should be destroyed. Livestock contaminated lightly by phosgene, nerve agents, mustards, and arsenicals (such as vapor or liquid) may be slaughtered in the early stages of poisoning before the full effects of exposure are shown. If these animals are slaughtered in the preliminary stages of poisoning and all tissues exposed to the agent (the head, blood, lungs, organs, and local areas) are discarded, there is no danger in consumption of the meat, provided the animal passes a pre-slaughter and slaughter inspection. This is true even of animals poisoned by arsenical agents since the edible tissue will contain amounts of arsenic too small to be toxic. Organs (liver, brain, heart, kidney, and lungs) will contain more arsenic than the musculature and are discarded. The meat must be well cooked. Personnel involved in slaughtering procedures must be careful to prevent spreading contamination to the meat and to themselves.

(10)   Decontaminating forage and grain exposed to only chemical agent vapors is by aeration. Aerated supplies, especially if mixed with larger amounts of uncontaminated supplies, produces no ill effects when fed to animals. Forage or grain heavily contaminated by liquid vesicants, especially arsenicals, should not be used.

Table F-8. Chemical Decontamination of Unpackaged Food

Chemical Agent	Fatty Foods (Butter, Bacon, Milk, Cheese, Ham)	Nonfatty Foods, High Water Content, Crystalline (Fruits, Vegetables, Salt, Sugar)	Nonfatty Foods, Low Water Content, Amorphous (Flour, Cereals, Bread, Peas)
Nerve Agents
Vapor, Heavy	Destroy	Destroy, Unless Possible to Boil After Airing 48 Hours	Air for 48 Hours, Then Boil
Vapor, Light	Destroy	Air for 48 Hours, Then Boil	Air for 48 Hours, Then Boil
Liquid	Destroy	Destroy	Destroy
Mustards
Vapor	Remove 1-3 cm of Outer Layer and Wash With 2% Sodium Bicarbonate Solution. Boil for at least 30 Minutes. Destroy Milk.	Wash With Water, air for 48 Hours	Wash With Water, air for 48 Hours
Liquid	Destroy	Destroy	Destroy
Arsenicals	Destroy	Destroy	Destroy