Effect of protective agents, rehydration media and initial cell concentration on viability of Pantoea agglomerans strain CPA-2 subjected to freeze-drying.
The effect of initial cell density, protective agents and rehydration media on the viability of biocontrol agent Pantoea agglomerans CPA-2 when subjected to freeze-drying was studied. Several additives were tested as protective agents against freeze-drying injury. Maximum viability of the bacterial cells was obtained with disaccharides (survival levels > 60%). Freeze-dried samples were rehydrated with several media; the highest percentage viability was obtained with 10% non-fat skim milk (100%+). The effect of initial bacterial load on the final recovery was dependent on protectant but not on rehydration media. Sucrose was an effective protectant when a high initial concentration (10(10) cfu ml(-1) was used; the opposite occurred with non-fat skim milk. The use of 10(10) cfu ml(-1) as an initial concentration, sucrose as a protectant and non-fat skim milk as a rehydration medium enabled 100% of P. agglomerans viability to be conserved after freeze-drying. Results suggest the possibility of achieving a good formulation system for the studied biocontrol agent with a high number of viable cells to be used toward pathogens, which is desirable for the industrial development of the product.
Costa
E
E
Postharvest Unit, CeRTA, Centre UdL-IRTA, Lleida, Spain. elena.costa@irta.es
Usall
J
J
Teixidó
N
N
Garcia
N
N
Viñas
I
I
D000818:Animals; D003451:Cryoprotective Agents / Q000494:pharmacology*; D004187:Disaccharides / Q000494:pharmacology; D005440:Fluid Therapy; D005612:Freeze Drying; D008892:Milk; D020636:Pantoea / Q000187:drug effects*; D013395:Sucrose / Q000494:pharmacology
D003451:Cryoprotective Agents; D004187:Disaccharides; D013395:Sucrose