IRRADIATION OF SHREDDED CARROT IN MODIFIED ATMOSPHERE PACKAGING

Authors: Hagenmaier, Robert - Bob; Baker, Robert

Submitted to: Journal of Food Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/13/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: It is a fairly new development in the food industry to sell trimmed and cut vegetables and fruit as ready-to-eat products. The control of sanitation in manufacturing such products has not kept pace with sales, with the result that pre-cut vegetables and fruit are known to have caused food-borne diseases, particularly amongst those whose health is most at risk, such as those who have received radiation therapy. In fact, such individuals are often advised not to eat raw produce, whole or precut. Low-dose gamma irradiation has been approved by FDA as a means of reducing bacteria of foods. Most of the research done to date on irradiation of vegetables has used somewhat higher levels of irradiation than that approved by FDA, and have often looked at irradiation as the only means of reducing bacteria. In the current commercial method of preparing pre-cut vegetables, chlorine water is used to reduce bacteria counts. The study uses low-dose irradiation in combination with chlorine water to prepare shredded carrots that have much reduced bacteria counts - perhaps low enough to be acceptable as food even for individuals whose health is most at risk.

Technical Abstract: Using a combination of chlorine and low-dose irradiation, shredded carrots were produced that had aerobic plate counts of only 200 cfu/g. The respiration rate of irradiated, shredded carrots was temporarily elevated by irradiation. Oxygen content of the headspace gas was virtually the same for irradiated and nonirradiated carrots. The headspace CO2 was temporarily boosted by irradiation, but after 9 days storage was virtually the same for both irradiated and control. After 8 days storage at 2øC in modified atmosphere packaging the respiration rate at ambient oxygen concentration was lower for irradiated carrots than for control, although there was no corresponding change in the rate of ethanol product. Irradiation resulted in no readily apparent change in type of microorganism, and the survivors grew at about the same rate as the original population, doubling in about 1-2 days at 2øC, or in a few hours if stored at 22øC.