Effect of Gamma Irradiation on the Bacteriological and Sensory Analysis of Raw Whole Milk under Refrigeration

Abstract

The aim of this study was to evaluate the effect of gamma irradiation (1, 2 and 3 kGy) on the bacteriological quality and sensory perception of refrigerated raw whole milk. Moreover, physiochemical and bacteriological parameters were monitored during 60 days of storage at 4C. All of the irradiated samples, mainly 2 and 3 kGy, exhibited a lower (P < 0.05) bacterial load than the nonirradiated samples. During storage, the mesophilic count and titratable acidity did not increase in the irradiated samples. The consumers were able to differentiate all of the irradiated samples from the control group (P < 0.05); however, positive attributes were used to describe the irradiated samples. The present study indicates that the 2 kGy irradiation dose improved the bacteriological quality of raw whole milk and likely did not negatively affect sensory characteristics by maintaining a constant mesophilic count and titratable acidity over the 60 days of refrigerated storage. PRACTICAL APPLICATIONSThe prevalence of foodborne diseases and huge economic losses from food industries in developing countries has markedly increased. Taking into account the dairy products, raw milk represents the main source of foodborne infections. To investigate an alternative conservation method, three gamma irradiation doses (1, 2 and 3 kGy) were applied in refrigerated raw whole milk. After, bacteriological and sensory qualities of this milk were investigated. In addition, mesophilic count and titratable acidity were analyzed during 60 days of storage under refrigeration (4 ± 1C). On 0 day, all irradiation doses decreased (P < 0.05) the bacterial load of raw whole milk compared with nonirradiated samples. Moreover, both parameters evaluated during storage period (mesophilic bacterial count and titratable acidity) were stable in samples treated with 1, 2 and 3 kGy. However, rancid odors and flavors were perceived on the samples irradiated with 3 kGy. Therefore, in our study, the 2 kGy dose was recommended for raw whole milk because of the positive effects on bacterial quality and minimal sensory changes.

Stability of antibodies and proteins in camel whey powder treated by Gamma-irradiation during radurisation process

“…In agreement with our results, de Oliveira Silva et al 2015, reported a significant decrease in the bacterial load by two to three log cycles in milk samples exposed to irradiation doses of 1, 2 and 3 kGy doses, compared to the nonirradiated control sample (de Oliveira Silva et al, 2015).…”

Current progress of emerging technologies in human and animals’ milk processing: Retention of immune‐active components and microbial safety

“…Gamma irradiation extends the shelf-life of food products by destroying bacterial nucleic acids (DNA) leading to the elimination of microbial contamination. de Oliveira Silva et al (2015) investigated the effect of gamma irradiation (1, 2, and 3 kGy) on the bacteriological and sensory quality of raw milk, and found that milk irradiated at 2 and 3 kGy had a significantly (p < 0.05) lower bacterial load. In addition, they recommended a 2 kGy dose for raw whole milk because of the positive effects on bacterial quality and minimal sensory changes.…”

Implications of the use of irradiation in the processing of animal origin foods: Review

“…Crab meat Santos et al (2010) Gamma / Co60 1.0, 2.0, 3.0 CBHAM, CBHAP, Staph. aureus, E. coli Raw milk Silva et al (2015) Gamma / Cs137 0.3, 1.0 Trichinella spiralis Pork Sivinsk and Switzer (1985) Gamma / Co60 3.0, 5.0, 10…”