This study evaluated the effect of lactic acid bacteria (LAB, a mixture of Enterococcus faecium and Lactobacillus plantarum) supplementation, the storage temperature, and storage period on the fermentation characteristics and in vitro ruminal digestibility of a total mixed ration (TMR). The TMR was prepared into two groups, namely, CON (control TMR without the LAB) and ML (supplementing a mixture of E. faecium and L. plantarum in the ratio of 1% and 2% (v/w), respectively). Both groups were divided and stored at 4°C or 25°C for 3, 7, and 14 d fermentation periods. Supplementing LAB to the TMR did not affect the chemical composition of TMR except for the lactate and acetate concentration. Storage temperatures affected (p<0.05) the chemical composition of the TMR, including pH, lactate, and acetate contents. The chemical composition of TMR was also affected (p<0.05) by the storage period. During in vitro rumen fermentation study, the ML treatment showed lower (p<0.05) dry matter digestibility at 24 h incubation with a higher pH compared to the CON. There was no difference in the in vitro dry matter digestibility (IVDMD) of TMR between the CON and ML treatment however, at 24 h, ML treatment showed lower (p<0.05) IVDMD with a higher pH compared to the CON. The effects of storage temperature and period on IVDMD were not apparent at 24 h incubation. In an in vivo study using Holstein steers, supplementing LAB to the basal TMR for 60 d did not differ in the final body weight and average daily gain. Likewise, the fecal microbiota did not differ between CON and ML. However, the TMR used for the present study did include a commercial yeast in CON, whereas ML did not; therefore, results were, to some extent, compromised in examining the effect of LAB. In conclusion, storage temperature and period significantly affected the TMR quality, increasing acetate and lactate concentration. However, the actual effects of LAB supplementation were equivocal.

Fermented total mixed ration (TMR) is a novel feed for ruminants in South Korea. The purpose of this study was to evaluate the effects of lactic acid bacteria (LAB) on the quality of TMR and in vitro ruminal fermentation. Strains of three LAB spp. (Lactobacillus plantarum, L. brevis, L. mucosae) were used in fermentation of TMR. Inoculations with the three LAB spp. lowered pH and increased concentrations of lactic acid, acetic acid, and total organic acid compared to non-LAB inoculated control (only addition of an equivalent amount of water) (p<0.05). Bacterial composition indicated that aerobic bacteria and LAB were higher. However, E. coli were lower in the fermented TMR than those in the control treatment (p<0.05). Among the treatments, L. brevis treatment had the highest concentration of total organic acid without fungus detection. Gas production, pH, and ammonia-nitrogen during ruminal in vitro incubation did not differ throughout incubation. However, ruminal total VFA concentration was higher (p<0.05) in the LAB spp. treatments than the control treatment at 48 hours. Overall, the use of L. brevis as an inoculant for fermentation of high moisture. TMR could inhibit fungi growth and promote lactic fermentation, and enhance digestion in the rumen.

We compared between an automated most-probable-number technique TEMPO®TVC and traditional plating methods PetrifilmTM for estimating populations of total aerobic bacteria in various livestock products. 257 samples randomly selected in local retail stores and 87 samples inoculated with E. coli ATCC 25922, Staphylococcus aureus ATCC 12868 were tested in this study. The degree of agreement was estimated according to the CCFRA (Campden and Chorleywood Food Research Association Group) Guideline 29 and the agreement indicates the difference of two kinds methods is lower than 1 log base 10(log10). The samples of hams, jerky products, ground meat products, milks, ice creams, infant formulas, and egg heat formed products were showed above 95% in the agreement of methods. In contrast, proportion of agreement on meat extract products, cheeses and sausages were 93.1%, 92.1%, 89.1%, respectively. One press ham and five sausages containing spice and seasoning, two pork cutlets containing spice and bread crumbs, two meat extract product and two natural cheeses and one processing cheese with a high fat content, and one ice cream containing chocolate of all samples showed the discrepancy. Our result suggest that TEMPO®TVC system is efficient to analyses total aerobic bacteria to compare manual method in time-consuming and laborious process except livestock products having limit of detection.

In this study, we investigated culturable bacterial abundance in various crops. Total culturable aerobic bacteria in tomato plants were enumerated on NA and it showed that the amounts of viable bacterial cells were changed among the different parts of the plants (roots, stems, and fruits), ranging between log 1 and 4 per g sample. To investigate the bacterial abundance dynamics in different crops, culturable aerobic bacterial cell numbers were enumerated on NA and compared between the samples (tomato fruit, sesame leaf, and green onion) harvested freshly from one field trial (Yangsan, Korea). In this trial, the number of total culturable aerobic bacteria of the samples were 8 times higher in sesame leaves and green onions compared to the tomato fruits in the field. Interestingly, culturable aerobic bacteria on MRS were only found in sesame leaves, whereas lactic acid bacteria were not detected in tomato fruit and green onion samples in this field. We also found that the field location (Yangsan, Gangneung, or Busan) influenced the number of culturable aerobic bacteria on the surface of the crops. Tomato samples freshly harvested from the different field locations were tested and showed that the amounts of culturable aerobic bacteria on NA and MRS agar were significantly different based on the field locations of the samples. Finally, lactic acid bacteria were isolated from all the tomato and sesame leaf samples used in this study, showing 20 and 28 morphological diversity. With these isolates, we will be able to conduct further biological and functional investigation to develop a new probiotic strain originated from the crops in Korea.