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Effect of gamma irradiation on microbiological and physico-chemical quality of meatballs

100%

Vural A. , Aksu H.

Medycyna Weterynaryjna

2006

tom 62

nr 09

1011-1015

The aim of the study was to examine the effects of gamma irradiation on the microbiological and physio-chemical characteristics of meatballs. Meatball samples were produced experimentally and divided into six subgroups. The first group (control group) was not subjected to an irradiation process, and the remaining groups were subjected to irradiation at doses of 1, 2, 3, 5 and 7 kGy. All groups were analyzed on days 0 (the day of irradiation process), 5, 10, 15, 20 and 30. The study revealed a significant reduction in the microbiological flora of the meatballs in relation to gradual increases in irradiation dosage. Faecal coliform bacteria counts, coliform bacteria counts and S. aureus counts were eliminated after applying 2 kGy, 3 kGy and 7 kGy irradiation doses, respectively. During storage at 4±1 °C, the bacterial populations systematically increased. Compared to the control group, low dose irradiation did not significantly change pH values, but higher pH levels were determined during high doses of irradiation. Irradiation increased the peroxide levels, but this increase did not seem to correlate with irradiation dosage. FFA levels decreased in relation to increasing levels of irradiation dosage.

The influence of bacterial reduction on concentrations of sulphates in deep aquifers in river drainage basin

80%

Kotowski T. , Burkowska A.

Polish Journal of Environmental Studies

2011

tom 20

nr 2

Our study attempts to determine the influence of bacterial reduction on sulphate concentrations in groundwaters. A buried valley in a southeastern section of the Gwda River drainage basin was selected for fieldwork near the towns of Wysoka and Bądecz. Deep aquifers in the area are known for their high sulphate concentrations that result from pyrite oxidation by the Thiobacillus denitrificans bacteria. Isotope compositions of SO₄²⁻ ions show ³⁴S enrichment at lower sulphate concentrations, which might indicate bacterial reduction processes. Theoretical curves of SO₄²⁻ isotope composition and ion concentration change, drawn using a Rayleigh formula and the results of the determination of δ¹⁸O (SO₄²⁻) and δ³⁴S (SO₄²⁻) suggest widely varying intensities of the sulphate reduction processes. It can be estimated that bacterial reduction eliminated between 30% and in excess of 50% of the initial concentrations of SO₄²⁻ ions in individual cases.