Microbiological Quality of Fresh-Squeezed Orange Juice and Efficacy of Fruit Surface Decontamination Methods in Microbiological Quality UFUK BAGCI AND AYHAN TEMIZ* Department of Food Engineering, Hacettepe University, 06800 Beytepe, Ankara, Turkey MS 11-021: Received 17 January 2011/Accepted 15 April 2011 ABSTRACT 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. Consumption of fresh-squeezed fruit juices has in- creased in recent years due to their high nutritional value and superior taste (2, 14). The feature of fresh-squeezed fruit juice that sets them apart from conventional fruit juice products is the lack of pasteurization. Heating processes used in pasteurization of conventional juices increases shelf life by inactivating certain enzymes and microorganisms. However, flavor losses and heat-induced chemical changes are the main drawbacks of the pasteurization process, leading to a remarkable diminishing of the quality of the natural fresh juice (14, 27). Citrus juices are the most widely consumed fresh- squeezed fruit juices worldwide (19). Fresh-squeezed citrus juice is pure juice obtained from mature citrus fruit and has not been further pasteurized, frozen, or concentrated after extraction (15, 23). Among citrus juices, orange juice is the most appreciated and consumed because of its pleasant taste and its high content of vitamin C (20). Fresh fruit juices have a short shelf life, even when kept under refrigeration (0 to 4uC) (7). It has been recognized that the shelf life and quality of fresh juice products are directly related to the care and sanitation steps taken in fruit handling and processing. Reported initial microbial levels of fresh citrus juice vary from 1.3 to 5.3 log CFU/ml. Extremely high initial microbial levels may result from the use of deteriorated fruit, insufficient cleaning, or poor equipment sanitation (3, 9, 15). Acidic foods such as fruit juices were not recognized as vehicles of foodborne illness until major outbreaks involving Escherichia coli O157:H7 and Salmonella spp. in orange and apple juices occurred (6, 31). Pathogenic microorganisms do not grow in fruit juices due to their low pH but can survive and become adapted to acidic environments (12, 28). E. coli O157:H7 and Salmonella spp. can survive for extended periods of time in high-acid environments under refrigerated storage. Zhao et al. (33) reported that E. coli O157:H7 could survive up to 31 days at 8uC in unpasteurized apple cider (pH 3.6 to 4.0). Salmonella enterica serovars Hartford, Graminara, and Typhimurium have been shown to survive up to 24, 15, and 15 days, respectively, at pH 3.5 and 4uC storage temperature (18). In 2001, the U.S. Food and Drug Administration (FDA) established that juice processors were required to implement hazard analysis critical control point programs. The regulation requires implementation of a process capable of * Author for correspondence. Tel: z90 312 297 71 00; Fax: z90 312 297 21 23; E-mail: temiz@hacettepe.edu.tr. 1238 Journal of Food Protection, Vol. 74, No. 8, 2011, Pages 1238–1244 doi:10.4315/0362-028X.JFP-11-021 Copyright G, International Association for Food Protection Downloaded from http://meridian.allenpress.com/jfp/article-pdf/74/8/1238/1686433/0362-028x_jfp-11-021.pdf by guest on 15 June 2022