Identification of Microbial Isolates from Vacuum‐Packaged Ground Pork Irradiated at 1 kGy

Abstract

Bacterial cultures from irradiated (1 kGy) and nonirradiated, vacuumpackaged ground pork held at 5°C were isolated and characterized over a 12-day storage period. The initial flora of the meat was composed mostly of Pseudomonas sp. and Etzterobacter sp. Although the microflora of nonirradiated samples gradually shifted from Gram-negative to Gram-positive microorganisms, 76% of the isolates were characterized as Gram-negative at the onset of spoilage (9 days at 5°C). In contrast, the irradiated ground pork microflora was mainly Grampositive (66%) shortly after irradiation and increased to 97% after 9 days at 5°C. A total of 720 isolates were identified to genus.

Low‐dose Gamma Irradiation and Refrigerated FStorage in vacua Affect Microbial Flora of Fresh Pork

“…Serrutia represented 83% of all aerobic mesophilic isolates from nonirradiated samples stored in vacua at 2°C for 35 days. Ehioba et al (1988) reported mainly Gram-positive organisms in irradiated vacuumpackaged ground pork immediately following a dose of 1 kGy and during 12 days of refrigerated storage, as did we. However, they did not store samples beyond 14 days.…”

Effects of ionizing radiation on pork, beef, and turkey quality

“…Lefebvre et al (1992) observed that irradiation dose increased, the dominant group of bacteria shifted from gram-negative to gram-positive. Ehioba et al (1988) and reported that gram-positive organisms donainated the bacterial population of pork immediately after being irradiated at 1 kGy and persisted during refrigerated storage. Even though gram-positive organisms are more irradiation resistant than gram-negative organisms, they can be eluninated from a sample by medium-dose irradiation.…”

“…Research indicates 38 that gram-negative spoilage organisms are relatively sensitive to irradiation. A pronounced effect on the reduction and elimination of gram-negative spoilage organisms has been observed in meat products by low-and-medium dose irradiation (Niemand et al, 1983;Ehioba et al, 1988;Rodriguez et al, 1993).…”

“…Research has shown that the bacterial populations shift from radiation sensitive gram-negative to radioresistant gram-positive organisms a result of irradiation 50 (Ehioba et al, 1988;Lefebvre et al, 1992 Another approach to detect irradiated foods is to quantitate lipid derivatives that are produced by irradiation. Crone et al (1992) and Boyd et al (1991) studied the formation of 2-dodecylcyclobutanone (DCB), which is a radiolytic product of palmitic acid, in irradiated chicken.…”

Inactivation of 3-strain cocktail pathogens inoculated into Bajirak jeotkal, salted, seasoned, and fermented short-necked clam (Tapes pilippinarum), by gamma and electron beam irradiation

“…In addition, Gram-negative bacteria are more sensitive to irradiation than Gram-positives (Thayer, Boyd, & Jenkins, 1993). Several researchers have demonstrated that low dose irradiation, which could virtually eliminate Gram-negative bacteria in food, have a much smaller effect on Gram-positive bacteria (Ehioba et al, 1998;Thayer et al, 1993).…”