Development of a Lacticin 3147–Enriched Whey Powder with Inhibitory Activity against Foodborne Pathogens

381

276

Spray drying of skim milk was evaluated as a means of preserving Lactobacillus paracasei NFBC 338 and Lactobacillus salivarius UCC 118, which are human-derived strains with probiotic potential. Our initial experiments revealed that NFBC 338 is considerably more heat resistant in 20% (wt/vol) skim milk than UCC 118 is; the comparable decimal reduction times were 11.1 and 1.1 min, respectively, at 59°C. An air outlet temperature of 80 to 85°C was optimal for spray drying; these conditions resulted in powders with moisture contents of 4.1 to 4.2% and viable counts of 3.2 ؋ 10 9 CFU/g for NFBC 338 and 5.2 ؋ 10 7 CFU/g for UCC 118. Thus, L. paracasei NFBC 338 survived better than L. salivarius UCC 118 during spray drying; similar results were obtained when we used confocal scanning laser microscopy and LIVE/DEAD BacLight viability staining. In addition, confocal scanning laser microscopy revealed that the probiotic lactobacilli were located primarily in the powder particles. Although both spray-dried cultures appeared to be stressed, as shown by increased sensitivity to NaCl, bacteriocin production by UCC 118 was not affected by the process, nor was the activity of the bacteriocin peptide. The level of survival of NFBC 338 remained constant at ϳ1 ؋ 10 9 CFU/g during 2 months of powder storage at 4°C, while a decline in the level of survival of approximately 1 log (from 7.2 ؋ 10 7 to 9.5 ؋ 10 6 CFU/g) was observed for UCC 118 stored under the same conditions. However, survival of both Lactobacillus strains during powder storage was inversely related to the storage temperature. Our data demonstrate that spray drying may be a cost-effective way to produce large quantities of some probiotic cultures.Given that probiotic microorganisms play a role in promoting and maintaining health (29) has stimulated considerable interest in incorporating these into functional foods and pharmaceutical products. By definition, probiotics are "living microorganisms, which upon ingestion in certain numbers, exert health benefits beyond inherent basic nutrition" (13), and it is recommended that probiotic products contain at least 10 7 live microorganisms per g or per ml (15). Therefore, from a commercial point of view, an inexpensive method for large-scale production of cultures containing high levels of viable probiotic cells in a form suitable for product applications is highly desirable.In previous studies researchers have investigated the production of freeze-dried powders and frozen concentrates of probiotic Bifidobacterium and Lactobacillus spp. (10,12,24). However, there are many disadvantages associated with this approach; freeze-drying is time-consuming and expensive, there are high transport and storage costs associated with frozen concentrated cultures, and the freeze-thaw process is associated with a loss of culture viability. In comparison, spray drying, one of the predominant processing tools used in the dairy industry, can be used to produce large amounts of dairy ingredients relatively inexpensively; it has been estimated th...

Section: Resultsmentioning

confidence: 98%

“…Protease sensitivity was indicated by inhibition of the zone of clearing. Bacteriocin activity in the cell-free supernatant was determined as previously described (25). In addition, bacteriocin production was detected and bacteriocin activity was determined in spray-dried powders containing strain UCC 118 as follows.…”

Section: Methodsmentioning

confidence: 99%

Comparative Survival Rates of Human-Derived Probiotic Lactobacillus paracasei and L. salivarius Strains during Heat Treatment and Spray Drying

Gardiner

O’Sullivan

Kelly

et al. 2000

381

276

“…This study evaluates the fate of lacticin 3147 in the digestive tract, initially by means of in vitro/ex vivo simulation studies and subsequently in vivo using the pig as a model. A food-grade lacticin 3147 ingredient developed in our laboratory to facilitate food applications was employed (17,18). This spray-dried lacticin 3147 skim milk powder was manufactured as described previously (22) and reconstituted (10%, wt/vol) in sterile distilled water to prepare the reconstituted lacticin 3147 skim milk (RLSM) used in experiments.…”

mentioning

confidence: 99%

Fate of the Two-Component Lantibiotic Lacticin 3147 in the Gastrointestinal Tract

Gardiner

Rea

O'Riordan

et al. 2007

Self Cite

The component peptides of lacticin 3147 were degraded by ␣-chymotrypsin in vitro with a resultant loss of antimicrobial activity. Activity was also lost in ileum digesta. Following oral ingestion, neither of the lacticin 3147 peptides was detected in the gastric, jejunum, or ileum digesta of pigs, and no lacticin 3147 activity was found in the feces. These observations suggest that lacticin 3147 ingestion is unlikely to have adverse effects, since it is probably inactivated during intestinal transit.Lacticin 3147 is a lantibiotic produced by Lactococcus lactis (16,23). Its antimicrobial activity is mediated by the combined action of its component peptides, LtnA1 and LtnA2 (29). Like other bacteriocins, lacticin 3147 has a number of potential applications for both food and biomedicine (8). In particular, it offers advantages for use in foods, and previous studies have demonstrated its efficacy, both as a food biopreservative and in improving food quality (9, 27). While its broad spectrum offers certain advantages, it may also be a cause for concern, given that it has inhibited all gram-positive bacteria tested to date, including prominent members of the resident gut microbiota such as Lactobacillus, Enterococcus, and Streptococcus spp. (23). Indeed, the direct addition of lacticin 3147 to a human fecal fermentation gut model causes a dramatic reduction in gram-positive populations after only 30 min (22). Consequently, the ingestion of lacticin 3147 or other broad-spectrum bacteriocins in foods has the potential to perturb the commensal gut microbiota. Therefore, as part of a risk assessment for bacteriocins with potential applications in foods, it is important to determine their fate in the gastrointestinal tract (GIT) in vivo. This type of information is also important when considering potential therapeutic applications of orally delivered bacteriocins. This study evaluates the fate of lacticin 3147 in the digestive tract, initially by means of in vitro/ex vivo simulation studies and subsequently in vivo using the pig as a model. A food-grade lacticin 3147 ingredient developed in our laboratory to facilitate food applications was employed (17,18). This spray-dried lacticin 3147 skim milk powder was manufactured as described previously (22) and reconstituted (10%, wt/vol) in sterile distilled water to prepare the reconstituted lacticin 3147 skim milk (RLSM) used in experiments.To test lacticin 3147's sensitivity to a range of proteolytic enzymes representative of those found in the mammalian GIT, RLSM was incubated at 37°C for 3 h with 25 mg/ml trypsin,

“…Examples of this are the LAB AMPs nisin and lacticin 3147, both of which are used as food preservatives (7,14). The latter is also used for preventing bovine mastitis (20).…”

mentioning

confidence: 99%

Strong Synergy between a Eukaryotic Antimicrobial Peptide and Bacteriocins from Lactic Acid Bacteria

Lüders

Birkemo

Fimland

et al. 2003

The antimicrobial effect obtained upon combining the prokaryotic antimicrobial peptides (AMPs; more commonly referred to as bacteriocins) pediocin PA-1, sakacin P, and curvacin A (all produced by lactic acid bacteria [LAB]) with the eukaryotic AMP pleurocidin (from fish) has been investigated. The three LAB AMPs alone were active against gram-positive Listeria ivanovii bacteria at nanomolar concentrations, whereas they were inactive against gram-negative Escherichia coli bacteria. Pleurocidin alone was active against both of these types of bacteria at micromolar concentrations. Little if any synergy between the LAB AMPs and pleurocidin against the gram-positive L. ivanovii strain was obtained. In contrast, the LAB AMPs and pleurocidin acted highly synergistically against the gram-negative E. coli strain. Nanomolar concentrations of LAB AMPs increased the growth inhibitory potency of pleurocidin by about fourfold. When micromolar concentrations of LAB AMPs were combined with 2 g of pleurocidin/ml, 100% growth inhibition was attained, whereas pleurocidin alone at a concentration of 2 g/ml gave no growth inhibition. Most noteworthy, when high concentrations (128 g/ml) of pleurocidin in the absence of LAB AMPs were used over a long period of incubation (1 week), some growth of E. coli was observed, whereas 16 g of pleurocidin/ml completely abolished growth in the presence of 64 to 128 ng of LAB AMPs/ml over the same period of time. The results clearly demonstrate that combining eukaryotic and prokaryotic AMPs can greatly increase the specific activity and broaden the target-cell range of these peptides.