L. acidophilus

The main species currently considered or used for the development of probiotic products in pig and poultry are L. reuteri, L. acidophilus, L. rhamnosus, L. plantarum, L. delbrueckii subsp. bulgaricus, L. lactis and L. brevis (Massi et al 2006 Bilgili and Moran, 1990). 

A Lactobacillus strain was recently shown to inhibit competitively adhesion of enteropathogenic E. coli to pig ileum and interfered with bacterial attachment to the mucosal layer of ileal conducts (Blomberg et al., 1993). Although L. acidophilus inhibits the adhesion of several enteric pathogens to human intestinal cells in culture, when pathogen attachment preceded L. acidophilus treatment, no inhibitory interference occurred indicating that steric hindrance of site occupation is important in the inhibition of adhesion. Thus, therapeutic use is likely to be limited to preventive application of probiotics. 

Table V. Inhibition of Pathogens by L. acidophilus in Associative Culture...

Acidophilus milk is a sharp, harsh, acidic cultured milk produced by fermenting whole or skim milk with active cultures of Lactobacillus acidophilus. Honey, glucose, and tomato juice may be added as nutrients to stimulate bacterial growth and contribute flavor. Plain acidophilus milk has the same composition as whole milk or skim milk, except that part of its lactose is converted to 0.6 to 1% lactic acid by the culture organisms. Speck (1976), who proposed the addition of L. acidophilus to pasteurized milk (sweet acidophilus milk), described the beneficial effects of implanting the organisms in the human intestines. 

Sweet acidophilus milk differs from conventional acidophilus milk in that a high concentration of viable L. acidophilus organisms is added to cold pasteurized milk and kept cold. At the low storage temperature (4.4 °C) these organisms do not multiply, so the flavor and other properties of sweet acidophilus are identical to fresh fluid milk. The inoculated milk is promoted largely because it contains several million viable L. acidophilus cells per milliliter. 

When mixed cultures are frozen, there may be changes in the proportion of each organism that will remain viable under different conditions. Jabrait (1969) froze a mixed culture composed of S. lactis andL. acidophilus used to manufacture bioghurt (a German yogurt-like food). When the culture was stored at 0°C, 53% of the viable cells were S. lactis and the remainder were L. acidophilus. At —30°C, 57% were S. lactis, but at -35° and -40°C the proportions of the two organisms were approximately equal. The total viable population at 0°, -20°, and -35°C were 1010, 1010, and 109 per milliliter, respectively. 

Use of fermented whey as a food has been suggested. Jagielski (1871) combined whey and lactose with an appropriate culture and produced a whey kumiss. Later, Krul kevich mixed equal volumes of whey and buttermilk with kumiss yeasts, L. bulgaricus, and L. acidophilus. The finished product is claimed to resemble kumiss (Marth 1974). A condensed whey food composed, in part, of whey fermented by L. bulgaricus and P. shermanii has been described in a patent issued to Meade et al. (1945). Additional information on fermenting whey is given by Friend and Shahani (1979). 

A potential mechanism of action by which potential probiotic strains may impede pathogens is through the modulation of gene and/or protein expression patterns through bacterial signaling mechanisms. Interestingly, cell-free supernatants of L. acidophilus have been shown to inhibit... 

The inhibitory effects of the essential oils of coriander on the mycelial growth and ochra-toxinA production by A. ochraceus NRRL 3174 were studied by Basilico and Basilico (1999). Sage and coriander showed no important effect at any of the concentrations studied. Meena and Sethi (1994) also studied the potential of coriander oil in the control of A. niger, Saccharomyces cerevisiae, Mycoderma sp., L. acidophilus and Bacillus cereus. 

Talwalkar A, Kailasapathy K (2004) The role of oxygen in the viability of probiotic bacteria with reference to L. acidophilus and Bifidobacterium spp. Curr Issues Intest Microbiol 5 1-8... 

Other approaches to enhance the conversion of LA to CLA are found in immobilization techniques. Immobilized cells of Lactobacillus reuteri were 5.5 times more efficient in producing CLA than washed cells grown under optimized conditions (Lee et al, 2003a, 2003b). Improved CLA production was also observed with the immobilized cells of L. delbrueckii ssp. bulgaricus and L. acidophilus in polyacrylamide and chitosan (Lin et al., 2005). The major CLA isomers produced by these immobilized cells were c9, tll-CLA and t9, tll-CLA. 

Much of the work involving reduction of pathogens by LAB has been done in poultry and has focused on the reduction of Salmonella, but some work has also been done on inhibition of Campylobacter. The most commonly studied defined organisms are strains of Lactobacillus, especially L. acidophilus. However, the results obtained from the studies to demonstrate the efficacy of DFMs have been controversial. Additionally, work done on undefined cultures also indicates that pathogen reductions can occur using species other than lactobacilli. 

Watkins et al. (1982) administered L. acidophilus (unknown orgin) to 2-day-old chicks and subsequently challenged the chicks with pathogenic E. coli. The mortality rate of chicks not administered the L. acidophilus was 66.7%, whereas that of the ones fed the DFM was only 3.7%. A follow-up... 

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