(3) Some products can be decontaminated by washing, peeling, or trimming the outer skin or leaves. Decontaminate potatoes and hard-skinned fruits and vegetables by washing or scrubbing under running water, followed by peeling or scraping, then washing again. Potatoes, carrots, beets, and turnips can be washed at the supply depot. However, do not wash beans, rice, and onions until they are delivered to the field kitchen; washing reduces their storage quality and shelf life. Citrus fruits, pineapples, corn, peas, beans, melons, pumpkins, cabbage, and nuts can be peeled. Decontaminate cucumbers, tomatoes, cherries, cranberries, grapes, pears, plums, and thin-skinned squash by soaking in a water or detergent solution and rinsing with vigorous agitation or brushing. Apricots, peaches, most berries, asparagus, broccoli, and leafy vegetables cannot be satisfactorily decontaminated because of fuzzy surfaces, irregular shapes, or small size, which makes washing difficult.
- Fresh carcass meat, sausages, and fish can be decontaminated by several washings with cold water. The exterior layer of the food item is removed if radioactivity is still present. There is, however, a risk of contaminating the inner parts of the foodstuff in the process. Cooking with several changes of water is the last step in decontamination.
Table J-1. Decontamination of Food Supplies
| SURFACE OR MATERIAL | TYPE OF CONTAMINATION | ||
|---|---|---|---|
| CHEMICAL | BIOLOGICAL | NUCLEAR | |
| CANNED, BOTTLED, OR PROTECTED BY IMPERMEABLE CONTAINER. | IMMERSE IN BOILING, SOAPY WATER FOR 30 MINUTES AND RINSE. | WASH WITH SOAP AND WATER, THEN IMMERSE IN DISINFECTANT SOLUTION. (IMMERSE IN BOILING WATER FOR 30 MINUTES. FOOD DISINFECTANT, OR 1/3 CANTEEN CUP OF HOUSEHOLD BLEACH IN 10 GAL OF WATER). | WASH WITH SOAP AND WATER, RINSE. BRUSH, WIPE CHLORINE, FOOD CONTAMINATION FROM SURFACE OF CONTAINER. |
| SPRAY WITH DS2 AND RINSE | |||
| WASH IN HOT, SOAPY WATER, RINSE, AND AERATE. | BOIL IN WATER 15 MINUTES; NOT EFFECTIVE ON TOXINS AND SOME SPORES. | ||
| IMMERSE IN 5% SODIUM CARBONATE (4 LB WASHING SODA IN 10 GAL WATER), RINSE WITH POTABLE WATER. | |||
| IMMERSE IN HOUSEHOLD BLEACH SOLUTION (1/2 GAL BLEACH IN 25 GAL WATER) FOR 30 MINUTES THEN RINSE AND AERATE FOR 10 MINUTES. | |||
| IMMERSE IN HTH SOLUTION (1/2 LB IN 25 GAL WATER) 20 MINUTES, THEN RINSE. | |||
| IMMERSE IN STB SOLUTION (1 LB IN 25 GAL WATER) 30 MINUTES, THEN RINSE. | |||
| IMMERSE IN 2% PERACETIC ACID FOR 10 MINUTES, RINSE, AND AERATE FOR 10 MINUTES. | |||
| NOT CANNED OR IMPERMEABLE CONTAINER. | FOOD KNOWN OR SUSPECTED TO BE CONTAMINATED SHOULD NOT BE CONSUMED UNTIL APPROVED BY VETERINARY PERSONNEL. | BOIL IN WATER 15 MINUTES. COOK. IMMERSE IN OR SPRAY WITH 2% HOUSEHOLD BLEACH SOLUTION. PACKAGED, PEELED, OR PARED FOOD MAY BE IMMERSED OR SPRAYED. | WASH OR TRIM CONTAMINATION FROM UNPACKAGED FOOD. |
- Decontaminate hard cheeses, margarine, and butter by cutting off the outer layer to a depth of 2.5 to 3 cm.
- Let cooking oils stand for 3 to 5 days, then pour off the contaminated layer; use a funnel to control spillage.
- Nonperishable items that are hard to decontaminate, such as flour, sugar, and salt, can be set aside allowing natural radioactive decay. When supplies are short, dilute the contamination by mixing with uncontaminated food. This will reduce the total amount of radioactive exposure in foods prepared using these contaminated items.
- Decontaminate air permeable, double-sacked goods by removing the outer sack. If the inner sack is free of radiation, double sack the food again to restore protection. However, when contamination is present on the inside bag, the food in contact with the bag is likely to be contaminated. Three methods can be used to handle this type of contaminated product. The easiest method involves spraying the bag of dry goods (except sugar or salt) with water. This will wet a layer of the food inside the bag. The wet layer can be removed when the bag contents are emptied. The uncontaminated contents are scooped back into clean packaging. Another method involves using melted paraffin to uniformly coat the outside of the bag. The paraffin solidifies after 30 to 40 minutes, and then the bag with the radioactive contamination can be removed from the contents. Although this method will seal the radioactive substance in the wax, it probably will not remove the layer of contaminated food product inside the bag. For the third method, form a piece of sheet metal into a cylinder the same height as the bag and 4 to 6 cm smaller in diameter. Insert the cylinder into the bag, then remove the top 3 to 4 cm of the contaminated product. Carefully scoop the remaining product out into a clean sack. With the cylinder still in place, fold the bag down catching the contaminated product on plastic sheeting, or a tarpaulin. When using this method, mixing the contaminated portion with the uncontaminated portion is a problem. Check for contamination remaining in the product.
- Boiling or cooking has no effect on radioactive contamination.
(4) Group IV—Food contaminated through the food chain. It is not practical to decontaminate this food. Meat and milk are the two most common foodstuffs contaminated in this way.
- Milk may be decontaminated to a safe level by a complicated ion exchange process. The I-131 activity will decline rapidly during storage of milk and milk-products, although the Cesium and Strontium activity will remain almost constant for years. In an area with high-level fallout, milk is withdrawn from human consumption. The duration of withdrawal will be dependent upon the type of fallout and levels.
- Meat may be decontaminated to a safe level by soaking in water or brine. Cesium is loosely bound in the meat. By repeated soaking of meat cut in small pieces, most of the Cesium activity will be removed. Traditional meat preserving, such as salting with brine, will remove up to 60 to 70 percent of the Cesium activity. See [Table J-2.]
- Fruits, vegetables, root crops, and grain products may also contain hazardous amounts of radioactivity if ingested.