Inhibitory effect of ethanol and thiamine dilaurylsulfate against loosely, intermediately, and tightly attached mesophilic aerobic bacteria, coliforms, and Salmonella Typhimurium in chicken skin

Abstract

The effects of 3 ethanol levels (30, 50, and 70%) with and without thiamine dilaurylsulfate ( TDS ; 1,000 ppm) were evaluated for the reduction of natural mesophilic aerobic bacteria ( MAB ), coliforms, and inoculated Salmonella Typhimurium ( S. Typhimurium) in chicken skin. The chicken skin was inoculated with a 7 log cfu/mL suspension of S. Typhimurium. Loosely, intermediately, and tightly attached cells were recovered from chicken skin through shaking at 200 rpm for 5 min, stomaching for 1 min, and blending for 1 min, respectively. Increasing the ethanol concentration reduced the number of MAB, coliforms, and S . Typhimurium on the chicken skin, whereas TDS treatment without ethanol was not effective. Intermediately and tightly attached microorganisms (total MAB, coliforms, and S. Typhimurium) were more resistant to chemical disinfectants than loosely attached microorganisms. The combination of 70% ethanol with TDS was most effective than the combination of TDS with lower concentrations of ethanol in reducing populations of loosely, intermediately, and tightly attached MAB (by 1.88 log cfu/g, 1.21 log cfu/g, and 0.84 log cfu/g, respectively), coliforms (by 1.14 log cfu/g, 1.04 log cfu/g, and 0.67 log cfu/g, respectively), and S . Typhimurium (by 1.62 log cfu/g, 1.72 log cfu/g, and 1.27 log cfu/g, respectively). However, the chicken skin treated with higher concentrations of ethanol was tougher ( P < 0.05) and more yellow and less red ( P < 0.05) than that treated with lower concentrations of ethanol or with water (control). On the other hand, a combination of 30% ethanol and TDS yielded the best results, showing the reduction greater than 0.5 log cfu/g in S. Typhimurium, with no negative effect on chicken skin color or texture. Thus, a combination of 30% ethanol and TDS appears to be the optimal treatment for reducing microbial contamination of skin-on chicken products to enhance poultry safety without decreasing food quality, and this treatment could be applied in the poultry industry.

Experimental Study on Long-Term Mechanical Properties of Prestressed Glulam Continuous Beams

“…Based on the previous experiments, it has been shown that when the initial stress of the prestressed steel wire was less than 0.5 times the value of the ultimate tensile strength Ry, the influence of the relaxation of the steel wire could be ignored [37][38][39][40][41][42]. The maximum initial prestress applied to the steel wire in this test was 0.3Ry (0.3Ry < 0.5Ry).…”

The antioxidant properties and microbial load of Moringa oleifera leaves dried using a prototype convective air-dryer

“…Besides, our test on MOL’s sanitiser potential revealed that no microbes were present on the Petrifilms upon combination with 70% ethanol. This was probably due to ethanol’s ability to freely enter microbes’ membranes and inhibit cross-linking of peptidoglycans ( Seo et al, 2020 ). More importantly, these results showed that the combination of MOL with ME and AE preparations in ethanol solutions does not compromise the efficacy of ethanol in microbial reduction.…”

Long-Term Loading Test of Reinforced Glulam Beam

“…In this test, the stress variation of the steel bars was caused by two factors, one was the relaxation of the steel bars, and the other was the creep characteristic of the glulam. Previous studies showed that the relaxation of the steel bars was not significant anymore when the initial stress of the prestressed steel bars was less than 0.5 times value of the ultimate tensile strength R y [26][27][28][29][30][31][32][33]. Since the maximum prestress applied in this study was 60 MPa < 0.5fu = 270 MPa, the stress variation caused by the relaxation of the steel bars was ignored, and it was considered that the stress variation of the steel bars was mainly caused by the creep of the glulam.…”