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dc.contributor.advisorOrellana-Feliciano, Lynette E.
dc.contributor.authorRivera-Forestier, Ileana I.
dc.date.accessioned2018-11-14T18:49:47Z
dc.date.available2018-11-14T18:49:47Z
dc.date.issued2009
dc.identifier.urihttps://hdl.handle.net/20.500.11801/1292
dc.description.abstractAlicyclobacillus acidoterrestris is a thermoacidophilic spore forming bacteria, which has the ability to survive traditional thermal process. Several studies have found that A. acidoterrestris can grow at temperatures from 20 to 55 °C and pH values form 2.5 to 6.0. The ability to survive high temperature and low pH is due to their unique membrane composition that possesses ω-cyclohexane fatty acids. This bacterium has been isolated from various types of habitats, but studies showed it is commonly found in soil and water. Since its discovery, this bacterium has been associated in the spoilage of many foods, especially acidic juices, such as orange juice, apple juice and fruits blend. The presence of Alicyclobacillus acidoterrestris has been reported in the United States and Europe causing economic loss due to the recall of the final product. No studies have been made in Puerto Rico regarding the presence of A. acidoterrestris in fruit juices. The main objective of this investigation is to set the first risk assessment report regarding the incidence of Alicyclobacillus acidoterrestris in orange juices. Orange samples were collected from a local juice processor in western Puerto Rico. The samples were divided into groups: with and without wash; to each group two different treatments were applied: heat shock versus no heat shock. K-Agar, Orange Serum Agar and Potato Dextrose Agar were used for microbiological isolation and identification. All microbiological mediums were acidified with tartaric and malic acid (pH 3.7) and incubated at 43 °C for 48 hr. Physical-chemical analyses were done to determine variations in pH, Brix and color. A. acidoterrestris was not isolated in orange juice from local producers in Puerto Rico under the conditions tested. No significant changes were detected in the physical chemical properties of the orange juice.
dc.description.abstractAlicyclobacillus acidoterrestris es una bacteria formadora de esporas que tiene la capacidad de sobrevivir tratamientos térmicos tradicionales. Estudios han revelado que A. acidoterrestris puede crecer y desarrollarse a temperaturas entre 20-55 °C y a pH de 2.5-6.0. La capacidad de sobrevivir temperaturas altas y pH bajos se debe mayormente a la composición única de su membrana, la cual consiste de ácidos grasos omega ciclohexano. Esta bacteria ha sido aislada en varios tipos de ambientes, pero estudios revelan que proviene comúnmente del suelo y el agua. Desde su descubrimiento, esta bacteria ha estado asociada al deterioro de alimentos, especialmente jugos ácidos como: jugos de naranja, manzana y frutas. La presencia de Alicyclobacillus acidoterrestris ha sido reportado en Estados Unidos y Europa causando pérdidas económicas debido al retiro del producto. En Puerto Rico no se ha realizado estudio alguno que relacione la presencia del A. acidoterrestris en jugos de frutas. El objetivo principal de esta investigación fue realizar el primer avalúo de riesgo para determinar la incidencia de A. acidoterrestris en el jugo de naranja. Las muestras de jugos de naranja fueron provistas por una planta procesadora de jugos localizada en el área oeste de Puerto Rico. Las muestras fueron divididas en dos grupos clasificados como naranjas lavadas y no lavadas; a cada grupo se le aplicó dos tratamientos diferentes: choque térmico versus no choque térmico. Los siguientes medios de cultivo fueron utilizados para aislar e identificar la bacteria: K-Agar, Orange Serum Agar (OSA), y Potato Dextrose Agar (PDA). Todos los medios de cultivo fueron acidificados utilizado ácido málico y ácido tartárico (pH 3.7) e incubados a 43 °C por 48 horas. Pruebas fisicoquímicas fueron utilizadas para determinar variaciones en pH, grados Brix y color. La bacteria A .acidoterrestris no fue recuperada en ninguno de los jugos de naranja de los procesadores locales en Puerto Rico. No se observaron cambios significativos en las propiedades fisicoquímicas del jugo de naranja.
dc.language.isoesen_US
dc.subjectAlicyclobacillus Acidoterrestrisen_US
dc.subjectCitrus sinensisen_US
dc.titleAnálisis de riesgo para la bacteria Alicyclobacillus Acidoterrestris en naranjas (Citrus sinensis) cosechadas en Puerto Ricoen_US
dc.typeThesisen_US
dc.rights.licenseAll rights reserveden_US
dc.rights.holder(c) 2009 Ileana Iris Rivera Forestier.en_US
dc.contributor.committeeNegrón de Bravo, Edna
dc.contributor.committeeHuertas, Javier
dc.contributor.representativeVargas, María
thesis.degree.levelM.S.en_US
thesis.degree.disciplineFood Science and Technology Programen_US
dc.contributor.collegeCollege of Agricultural Sciencesen_US
dc.contributor.departmentDepartment of Food Science and Technologyen_US
dc.description.graduationYear2009en_US


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