Abstract
The aim of this study was to evaluate the effectiveness of different UVC treatments, alone or in combination with ultra-high pressure homogenization (UHPH) on Bacillus subtilis spores in milk. Spores of B. subtilis (CECT4002) were inoculated in whole and skim milk to an initial concentration about 6 log CFU/mL. Milk was subjected to different ultraviolet radiation treatments at 254 nm (UVC) using a concentric tubular reactor in a dose ranging from 10 to 160 J/mL. Different number of passes were used to adjust the final dose received by the matrix. In general, increasing the number of passes (defined as number of entries to the tunnel-NET) increased the inactivation of spores of B. subtilis. The best lethality results (above 4 Log CFU/mL) were obtained by applying doses from 100 J/mL with several NET. When the same doses were achieved with a single pass lethality in most cases did not exceed 1 log CFU/mL. Increasing the NET also increased the likelihood for the spores to remain longer in the effective distance from the UVC source, estimated as 0.02 mm for whole milk and 0.06 mm for skim milk. Combination of UHPH and UVC did not clearly increase the efficiency of a single UVC treatment, and a lower lethality was even observed in some cases. UHPH treatments increased the turbidity and absorption coefficient (254 nm) of both whole and skim milk.
Highlights
Short-wave ultraviolet radiation (UVC) is a non-thermal technology proposed as an alternative to heat pasteurization that is being investigated nowadays for the reduction of microorganisms in liquid foods that may lead to spoilage and potential health risks for the consumers [1]
Single ultra-high pressure homogenization (UHPH) treatments, especially when they were combined with T3 UVC treatments, but lethalities were significantly (p < 0.05) lower than the obtained when with T3 UVC treatments, but lethalities were significantly (p < 0.05) lower than the obtained when the the UVC treatments were used alone
In matrices with low absorption coefficient different studies were conducted with B. subtilis spores, In matrices with low absorption coefficient different studies were conducted with B. subtilis a microorganism commonly used as a control organism in bioassays performed in water treated with spores, a microorganism commonly used as a control organism in bioassays performed in water
Summary
Short-wave ultraviolet radiation (UVC) is a non-thermal technology proposed as an alternative to heat pasteurization that is being investigated nowadays for the reduction of microorganisms in liquid foods that may lead to spoilage and potential health risks for the consumers [1]. UVC is lethal for most of microorganisms through the formation of pyrimidine dimers which blocks DNA duplication leading to cell death [6,7]. The microbiocidal effect of UVC has been tested in different foodstuffs, such as milk, demonstrating an effectiveness similar to thermal pasteurization [2,10,11,12,13,14,15,16,17,18,19,20,21,22].
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
