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Effect of Gamma Irradiation on the Bacteriological and Sensory Analysis of Raw Whole Milk under Refrigeration
Author(s) -
Oliveira Silva Adriana Cristina,
Oliveira Luiz A.T.,
Jesus Edgar F.O.,
Cortez Marco A.S.,
Alves Clara C.C.,
Monteiro Maria Lucia G.,
Conte Junior Carlos A.
Publication year - 2015
Publication title -
journal of food processing and preservation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.511
H-Index - 48
eISSN - 1745-4549
pISSN - 0145-8892
DOI - 10.1111/jfpp.12490
Subject(s) - titratable acid , food science , mesophile , raw milk , chemistry , gamma irradiation , sensory analysis , irradiation , biology , bacteria , genetics , physics , nuclear physics
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 4 C . 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 Applications The 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 ± 1 C ). 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.