BackgroundA mold strain thought to be suitable for dry-aging process was isolated. The information about the scientific aspects of molds related to dry-aging beef is scarce. We, therefore, conducted aging trials to determine the characteristics of the isolated mold strain associated with dry-aging process. Specifically, during the dry-aging of beef with the mold strain, the changes in the free amino acid content, hardness, productive loss, drip and cooking loss were analyzed. These characteristics were compared with those obtained while dry-aging in the absence of a mold.ResultsThe isolated mold strain was identified as Mucor flavus. The free amino acid content in the mold-aging beef decreased or remained constant during the aging process. However, that in the trimming sections of the beef dramatically increased in the presence of mold. In addition, hardness of mold-aging beef gradually decreased during the aging process and finally decreased significantly.ConclusionAmino acids such as GABA (gamma-aminobutyric acid), proline, and aspartic acid were produced by our mold strain, M. flavus during its growth on beef meat, and the mold conferred savory odors to the dry-aged beef.

BackgroundAging trials are conducted to determine characteristics associated with dry- and wet-aging processes of beef from delivered cows grown in Okinawa, i.e., dams that have finished giving birth (Okinawan delivered cow beef). Changes in free amino acids, hardness, and other factors were analyzed in round of Okinawan delivered cow beef during dry- and wet-aging processes along with a comparison with characteristics of beef imported from Australia.ResultsFunctional amino acids did not increase during both dry- and wet-aging processes. However, proteinogenic amino acids increased significantly (P < 0.05) and hardness tended to decrease during both dry- and wet-aging processes. On comparison between dry- and wet-aging processes by analysis of variance, drip and cooking losses were significantly lower during the dry-aging process than during the wet-aging process. However, there was no significant difference in free amino acids or hardness in this comparison.ConclusionThere was no significant difference between dry- and wet-aging methods for all studied variables related to free amino acids or hardness in this study.

Since 2002, papaya black rot has been spreading over several islands of Okinawa Prefecture, Japan. To devise a prevention strategy for the disease, microbiological research on the pathogen was conducted. Twelve strains were isolated from papaya infected with black rot showing symptoms such as water‐soaked lesions on stems and petioles, black spots on fruits, and rotted leaves turning yellow with necrotic spots. Through Koch's postulates, we confirmed that the isolated strains caused papaya black rot. Bacteriological assays showed that the strains have characteristics different from the type strains of Erwinia mallotivora, E. papayae, and E. psidii. Moreover, 16S rDNA sequence similarity searches showed that the isolated strains had less than 98.6% similarity with type strains. Additionally, phylogenetic analysis of 16S rDNA sequences suggested that the isolated strains were possibly a novel species belonging to the genus Erwinia, as the strains formed an independent cluster and had low sequence similarity with the type strains. Earlier studies indicated that papaya black rot is caused by E. cypripedii. Therefore, we propose to add the Erwinia sp. isolated in this study to the list of papaya black rot pathogens.

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In Okinawa, rate of increase in gross agricultural production during 2011‒2016 was the highest in Japan and sales of calves ranked fourth throughout Japan. Raising cattle by feeding high quality silage is beneficial both nutritionally and economically. However, little is known about lactic acid bacteria (LAB) present in silages made from tropical grass in Okinawa. To improve understanding of fermentation processes in silages, the LAB present in a range of silages (Digitaria eriantha, Megathyrsus maximus, Chloris gayana, Urochloa mutica, Sorghum sp. and Zea mays) were identified. All isolates were Gram-positive and mainly catalase-negative bacteria. According to morphological and biochemical characters, 37 isolates were divided into 16 groups and on the basis of 16S rDNA sequence analysis, 7 were identified as Lactobacillus plantarum, 3 as L. paraplantarum, 1 as L. brevis, 1 as L. acidipiscis, 3 as L. casei, 1 as L. fermentum, 9 as Weissella paramesenteroides, 1 as W. kimchii, 5 as Lactococcus lactis subsp. lactis, 2 as Lactococcus garvieae and 4 as Pediococcus pentosaceus. Some of this wide variety of LAB in Okinawan silage could be beneficial for improving quality of silages and further studies are planned to determine benefits of inoculating forage with particular strains at ensiling.