29G-6 |
Effect of temperature on growth and bacteriocin production by pediococcus sp. ctc 483 isolated from chicken liver |
I. MORENO1, R. Bromberg2, R. R. Delboni1, H. Cintra1, J. de Oliveira1, and A. L. S. Lerayer1. (1) Instituto de Tecnologia de Alimentos - ITAL, Avenida Brasil, 2880, Campinas - Sao Paulo, 13073-001, Brazil, (2) Meat Technology Centre, Instituto de Tecnologia de Alimentos - ITAL, Avenida Brasil, 2880, Campinas - Sao Paulo, 13073-001, Brazil The use of lactic acid bacteria to inhibit undesirable microorganisms in meat and meat products has been considered in biopreservation as an additional factor of safety. It is known, however, that foods are often packaged and stored at abusive temperatures and that some lactic acid bacteria are unable to grow at refrigeration temperatures in a way such as to ensure the production of bacteriocins at levels sufficiently high enough for microbial control. Pediococcus sp. CTC 483 isolated from chicken liver produces a wide spectrum bacteriocin with activity against Gram-positive pathogenic and meat spoilage microorganisms. Since pediocins have been found to be more appropriate for use in meats than nisin, the ability of this culture to propagate and produce bacteriocin at refrigeration temperatures was examined. Bacterial growth was similar at optimum and abusive temperatures, with the culture reaching the exponential phase of growth after 16 hours of incubation, and maximum cell density of 2.51 and 2.45, respectively. At storage temperature, cell density remained fairly constant during the first 24 hours. From that point on, accentuated growth was observed, reaching a peak of 2.11 after 114 hours. At -20oC, initial density was reduced by 27.8% after the first 24 hours, level which remained unchanged from that moment on. An exception was the culture incubated at freezing temperature in which bacteriocin production was detected after 16 hours. Bacteriocin production during incubation varied from 0.4 to 1.6 AU mL-1 at 4oC, from 0.8 to 1.6 AU mL-1 at 25 oC and from 0.4 to 0.8 AU mL-1 at 37oC. Although growth of Pediococcus sp. CTC 483 at storage temperature (4oC) was slower than at optimum (37oC) and abusive temperatures (25oC), no marked difference was observed in terms of bacteriocin production.
Session 29G, Food Microbiology: General
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