Effect of postharvest UV-C treatment on the microbial quality of ‘Şalak’ apricot

Abstract

Inactivation of natural flora found on cv. 'Şalak' apricot surfaces was investigated using a newly designed UV-C treatment system equipped with four UV lamps and a rotating roller bearing. Multiple Point Source Summation (MPSS) Model was used to estimate UV light intensity field in this processing chamber. Although MPSS model over-predicted the UV intensity data, light intensity profile showed a good agreement with the radiometric measurements. UV-C treatment of apricots resulted in 3-log reduction in the number of total mesophilic aerobic bacteria (TAPC) at 32.3 W m −2 of average UV light intensity for 16 min at 31.01 kJ m −2 of UV dose whereas 2.38-log reduction was achieved for yeast and mould count (YMC) after 4 min of UV exposure at 7.75 kJ m −2 of UV dose. On the other hand, complete inactivation of coliform bacteria was observed after all treatments. Statistical analysis indicated that further extension of the exposure time did not cause any significant effect on the inactivation of natural flora of apricot surfaces. Additionally, the inactivation data obtained for TAPC and YMC were modelled by using log-linear regression, Biphasic model, log-linear + tail, Weibull model, Weibull + tail, double Weibull and biphasic + shoulder models. The inactivation kinetics of TAPC and YMC were best described by log linear + tail model with the smallest root mean squared error (RMSE) and the highest regression coefficient (R 2 > 0.90). These results suggest that UV-C treatment can be applied to control the natural flora on cv. 'Şalak' apricots. Use of a rotating roller bearing is highly appreciated in UV-C systems to provide equal radiation among fruit surfaces.

Maintaining the Quality and Safety of Fresh-Cut Potatoes (Solanum tuberosum): Overview of Recent Findings and Approaches

“…The UV-C wavelength of 254 nm has the most effective germicidal effect. Numerous studies have reported effective UV-C inactivation of microorganisms, when applied to fresh or fresh-cut fruits and vegetables [178][179][180]. UV-C may also positively affect the storage of fresh and fresh-cut fruits and vegetables by reducing oxidative or cell wall-degrading enzyme activities [181,182].…”

Response Surface Methodology (RSM) Optimization of the Physicochemical Quality Attributes of Ultraviolet (UV-C)-Treated Barhi Dates

“…Such a reduction was attributed to the contribution of the UV-C on the disruption of the cell membrane integrity of microbes, damaging nucleic acids and inducing mutation, thereby retarding microbial growth [32]. However, at a higher UV-C dose, longer exposure time and longer storage time, the microorganisms might show different responses due to self-adjustment or adaptation of the microorganisms to the applied UV-C dose; the aggregation of microbial cells can form shields and prevent direct exposure to UV-C, developing resistance to the UV-C [35].…”

UV Processing and Storage of Liquid and Solid Foods: Quality, Microbial, Enzymatic, Nutritional, Organoleptic, Composition and Properties Effects

“…were achieved in fresh cut broccoli and green tomato after exposure to 0.0015 J cm À2 and 0.178 J cm À2 UV dose, respectively (Lim and Harrison, 2016;Martinez-Hernandez et al, 2015). On the other hand, less than 3 log reductions were recorded in apricot (3.1 J cm À2 ), watermelon (0.72 J cm À2 ), apple (2.4 J cm À2 ) and pear (0.17 J cm À2 ) samples after UV treatment at different UV dose levels (Hakguder and Unluturk, 2018;Syamaladevi et al, 2014;Manzocco et al, 2011;Artés-Hernández et al, 2010). Furthermore, higher than 1 log inactivation of hepatitis A virus (HAV) murine norovirus (MNV) was reported in UV treated blueberries (1331 mJ cm À2 ) (Butot et al, 2018).…”