The aims of this study were to evaluate the microbiological quality of fresh-squeezed orange juice and to reduce the microbial population by using various chemical and physical fruit surface decontamination methods. In the first step of the study, polyethylene-bottled fresh-squeezed orange juice samples purchased in Ankara, Turkey, were examined. The average aerobic plate count (APC) and coliform count (CC) varied within the ranges of 3 to 5 log CFU/ml and 1 to 4 log MPN/ml, respectively. Ten of 60 samples contained various levels of Escherichia coli, while Salmonella spp. and E. coli O157:H7 were not detected in any of the samples. Comparing the efficacy of various fruit surface decontamination methods on microbial population of oranges, the best results were obtained following two applications of submersion in boiling water and 5% H(2)O(2) solution for both the uninoculated and inoculated samples. Orange juice samples obtained from surface-inoculated and decontaminated oranges were also examined. We showed that about 17.4% of the E. coli population was transferred to orange juice after extraction, indicating the separation of microbial contaminants from fruit peel during extraction. Finally, the levels of microbial contamination occurred throughout the extraction process on the inner surfaces of a commercial juice extractor at one of the sale points investigated. Significant (P < 0.05) increases in the APC and CC were determined in surface samples of the extractor after the extraction. Surface decontamination and extraction are critical steps in fresh juice production for preventing microbial contamination. Immersion in boiling water for 0.5 min, without using any chemicals, can be offered as an effective method to reduce microbial population on orange surfaces.
In this study, the prevention of the attachment of test microorganism Enterobacter sakazakii onto stainless steel (SS 316) surfaces by radio frequency (RF) plasma polymerization (PlzP) technique using several hydrophilic monomers as precursors was reported. Different plasma conditions (RF discharge power of 20-80 W with exposure time of 10 min) were employed during the modifications. PlzP-modified surfaces were characterized in detail by static contact angle measurements in order to state the change of surface hydrophilicity. The surface topology of unmodified and PlzP [ethylenediamine (EDA)]-modified SS 316 plates was characterized by atomic force microscopy. The attachment of the model microorganism on the SS 316 surface modified by plasma using EDA at 45 W and 10 min was reduced by 99.74% in comparison to the unmodified control surface. For equilibrium adsorption behavior, Freundlich and Langmuir models were attempted and model parameters for Freundlich (K F and 1/n) and for Langmuir (a and b) were obtained. The values of the K F and 1/n were 5.6 and 0.58 and 0.9 and 0.39, respectively; the values of a and b were 25×10 4 and 1.82×10 −8 and 0.3×10 4 and 7.96×10 -8 , for bare and PlzP-EDA-modified SS 316 surfaces, respectively. As a result, PlzP technique was found to be an alternative simple method to decrease the microbial attachment and create bacterial anti-fouling surfaces.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.