OPCIONES SOBRE INDICES

Food irradiation is the process of exposing specific foods to a carefully controlled amount of energy delivered as gamma rays (cobalt-60), X-rays, or electrons. The advantages and the disadvantages of these technologies are summarized in Table 4.2. There is a long and successful history of using gamma rays (cobalt-60) for food irradiation for phytosanitary treatment. However, gamma ray technology suffers from key drawbacks in processing as well as other challenges associated with trans- portation, storage, disposal, and safeguarding a radioactive substance. Given the global security climate, the chances of large gamma ray irradiation facilities being approved are low (National Research Council 2008). Currently, the largest gamma ray irradiation facility in North America for food treatment is in Matehuala, Mexico. Similar to gamma rays, a major advantage of using X-rays is that entire pallets can be irradiated because this technology has high penetrating depth (60 - 400 cm), depending upon the energy used (Curry et al. 2000). X-ray technology overcomes

Table 4.2: Comparison of Irradiation Technology

Technologies Advantages Disadvantages

1) Well-established system 1) Replenishment of cobalt-60 2) Widely used phytosanitary 2) Low throughput

Gamma rays treatment 3) High acquisition cost of cobalt-60 (cobalt-60) 3) Low operating cost 4) Slow dose rate

4) High penetrating power 5) Moderate difficulty in logistics 6) Difficulty in getting the approval

1) Low throughput 1) High penetrating power 2) Slow dose rate

X-rays 2) Uses commercial electricity 3) High capital investment cost 4) Low energy utilization efficiency 5) Moderate difficulty in logistics

1) High throughput 2) High dose rate

3) Low capital investment 1) Low penetrating power EBeam and operating costs 2) Only suitable for certain

4) Uses commercial electricity dimensions of packaging 5) High energy utilization

efficiency

6) Easy to manage in logistics

some of the challenges associated with gamma rays by using commercial electricity to generate the sanitizing beam. However, there are still great disadvantages to the use of X-ray technology for phytosanitary treatment (Table 4.2). The only X-ray facility that is dedicated to phytosanitation is located in Kona, Hawaii.

EBeam technology, also known as beam pasteurization or electronic pasteuriza- tion, is a non-thermal treatment of food products and ingredients using electron beam linear accelerators to convert commercial electricity to highly energetic elec- trons. Compared to gamma rays and X-rays, the greatest advantages for eBeam are the high throughput (ten times more efficient than the generation of X-rays), the high dose rate (at least ten times higher than that of gamma rays or X-rays), the low capital investment and operating costs (much lower capital equipment cost than gamma rays or X-rays; and at least ten times lower operating cost than X-rays, but slightly more than gamma rays). The major disadvantage of eBeam technology is its

short penetration depth. The single 10 MeV eBeam, which is typical for phytosani- tary treatment, can barely reach a depth of approximately 5 cm in water or of 10 cm at a density of 0.5 g/cm3 _{(Diehl 1999). Thus, eBeam is not suitable for bulky food} packaging such as large crates used for shipping fruit. Single retail-ready packages of low density fruits and vegetables (i.e., mango, guava, sweet lime, tangerine, and manzano pepper) are currently treated in two large eBeam facilities in the U.S. in Sioux City, Iowa, and College Station, Texas. EBeam technology has the following characteristics:

• Green, chemical free technology: no chemicals are used for preservation of fresh foods.

• No environmental issues: eBeam has none of the environmental issues asso- ciated with radioactive waste, nor does it have challenges related to costs, transportation, storage, containment, and disposal.

• Use of commercial electricity: no replenishment of the irradiation source is needed.

• No loss of nutrients or compromise of food quality: eBeam does not change the temperature and does not alter the appearance, taste, or chemical makeup of the food product or its packaging.

• Effective: eBeam reduces or eliminates pathogens and pests, depending on the dose that is delivered.

• High throughput process: eBeam processing is at least ten times faster than conventional radioactive isotopes because it is based on electricity and not natural isotope decay.

• Easy to use and control: eBeam irradiation can be applied after packaging, and the whole process is automatically controlled.

• Cost-effective: depending on the commercial processing contract type, eBeam costs 5 to 8 cents to irradiate one pound of food, which is lower than using X-rays or gamma rays (approximately 10 cents per pound).

Table 4.3: Foods Currently Permitted to be EBeam Irradiated Under FDA’s Reg- ulations. [Source: FDA 2015. Regulatory Report: Irradiation of Food Packaging Materials].

Food Purpose Max. Allowable Dose

Fresh, non-heated Control of trichinella spiralis 1 kGy processed pork

Fresh fruits Pathogen control, 1 kGy

and vegetables maturation inhibition

All foods Arthropod disinfection 1 kGy Dry or dehydrated Microbial disinfection 10 kGy enzyme preparations

Dry or dehydrated Microbial disinfection 30 kGy spices/seasonings

Fresh or frozen, uncooked Pathogen control 3 kGy poultry products

Refrigerated, uncooked Pathogen control 4.5 kGy meat products

Frozen uncooked Pathogen control 7 kGy meat products

Fresh shell eggs Control of salmonella 3.0 kGy Seeds for sprouting Control of microbial pathogens 8.0 kGy Fresh or frozen Control of vibrio species 5.5 kGy molluscan shellfish and other foodborne pathogens

Fresh iceberg lettuce Control of food-borne pathogens, 4.0 kGy and fresh spinach and extension of shelf-life

Table 4.3 shows the foods that may be eBeam irradiated in the U.S. Recent studies find that doses of up to 1 kilogray (kGy) do not affect the quality or sensory attributes of the fruits (Shayanfar et al. 2015, Smith et al. 2015a, Smith et al. 2015b). Doses greater than 1 kGy significantly decrease ascorbic acid (vitamin C) concentrations during fruit storage, but do not affect overall antioxidant concentrations.