EFFICACY OF PULSED ELECTRIC FIELDS FOR LISTERIA MONOCYTOGENES INACTIVATION AND CONTROL IN HORCHATA |
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Authors: | M.V. SELMA,M.C. SALMERÓ N,M. VALERO, P.S. FERNÁ NDEZ |
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Affiliation: | Departamento Ingeniería de Alimentos y del Equipamiento Agrícola E.T.S.I.A., Universidad Politécnica de Cartagena Paseo Alfonso XIII 48 30203 Cartagena (Murcia), Spain; Departamento de Producción Vegetal y Microbiología Escuela Politécnica Superior de Orihuela Universidad Miguel Hernández de Elche Carretera de Beniel Km 3.2 03312 Orihuela (Alicante), Spain |
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Abstract: | Although Listeria monocytogenes is readily destroyed by thermal treatment, the factor that makes it particularly difficult to control in nonpasteurized foods is its ability to grow at refrigeration temperatures. In heat‐sensitive products, nonthermal technologies such as pulsed electric fields (PEF) as part of hurdle technology could minimize the presence of foodborne pathogens. The influence of PEF‐treatment conditions, inoculum size and substrate conditions on the inactivation and recovery of L. monocytogenes in a traditional low‐acid, vegetable beverage was investigated. The combined effect of PEF, low temperature (5C) and low inoculum level contributed to slow down the recovery of sublethally injured cells. However, at 12 or 16C, this elongation of the lag phases after PEF treatment observed for low inoculum levels of cells was not achieved. Therefore, to prevent the development of L. monocytogenes in low‐acid products by PEF, it may be necessary to combine it with low refrigeration temperatures during distribution and storage, as well as to achieve a very low initial contamination by pathogens in the raw ingredients. |
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