MICROBIOLOGICAL AND CHEMICAL INVESTIGATION OF OHMIC HEATING OF PARTICULATE FOODS USING A 5 kW OHMIC SYSTEM

Abstract

Lethality within food particles undergoing ohmic heating was investigated using microbiological and chemical marker measurements. Meatballs containing spores of B. stearothermophilus and precursors of chemical markers were thermally processed in a starch solution with 30–40% solids content using a 5 kilowatt (kW) ohmic system. Different temperatures, flow rates, holding tube lengths, and fluid electrical conductivities were used. Lethalities observed under various processing conditions were consistent with predictions. Higher lethality was observed, microbiologically and chemically, at the center of the meatballs rather than near the surface. A good correlation between the marker yield and the bacterial survivor population was obtained under various processing conditions. The results indicate that the chemical markers may be used to evaluate the distribution of lethality among different particles and the contribu‐

Caracterización fisicoquímica, funcional y química de harinas nixtamalizadas de maíz obtenidas por calentamiento óhmico y proceso tradicional

“…Martı´nez-Bustos, Lo´pez-Soto, Zazueta-Morales, and Morales-Sa´nchez (2005) reportaron que al usar CO en el procesamiento de almidones pregelatinizados no se aplica una fuerza al corte por lo cual solo ocurre una lixiviacio´n parcial de la amilosa. Por esta razo´n los componentes del almido´n se degradan levemente, lo que hace que se presente una alta accesibilidad al agua, aunado a la uniformidad del calentamiento, que se presenta durante el uso del CO (Kim et al, 1996;Skudder, 1988). La HC fue la que presento´el valor ma´s alto de CAA, lo que se debe a que esta´n adicionadas con gomas que incrementan la CAA (Flores, Martı´nez, Salinas, & Rı´os, 2002;Palacios-Fonseca, Va´zquez-Ramos, & Rodrı´guez-Garcı´a, 2009).…”

“…Entre las distintas industrias que aplican este tratamiento, son especialmente destacables las que han sido desarrolladas para la esterilizacio´n en flujo continuo de frutas, zumos de frutas, sopas, salsas o huevo lı´quido, sin embargo no existen reportes de su uso en el procesamiento de HMN. Se han reportado ventajas del uso del CO en el procesamiento de alimentos respecto al calentamiento convencional, entre las cuales se encuentran: disminucio´n de los tiempo de procesamiento, (lo cual permite que el alimento conserve su calidad nutrimental), la uniformidad del flujo de calor en el alimento (por lo que no existe sobrecalentamiento del producto), una eficiencia energe´tica del 90%, y adema´s es una tecnologı´a amigable con el ambiente, ya que no se genera remanentes durante el proceso (De Hallux, Piette, Buteau, & Dostie, 2005;Kim et al, 1996;Skudder, 1988).…”

Models for ohmic heating of solid–liquid mixtures under worst-case heating scenarios

“…A number of works have outlined safety criteria (Dignan, Berry, Pflug, & Gardine, 1989;Larkin & Spinak, 1996;Pflug, Berry, & Dignan, 1990). Protocols for microbiological validation have been investigated by various researchers (Bernard et al, 1990;Kim et al, 1996aKim et al, , 1996bSegner, Ragusa, Marcus, & Soutter, 1989).…”

Ohmic sterilization inside a multi-layered laminate pouch for long-duration space missions

“…Ohmic heating has potential as an alternative heating technology because of its capability of delivering high quality food (Kim et al, 1995), rapid heating, compact design, and minimal heating of the product surroundings (Jun and Sastry, 2005). Since heat is generated and distributed internally in the food, ohmic heating achieves close to 100% energy transfer efficiency (Sastry and Salengke, 1998) and eliminates the need for an external heat transfer medium and surfaces that are associated with conventional heating technologies.…”