Irish scientists report that a combination of five probiotic strains may reduce food poisoning by salmonella, if results of their pig study can be translated to humans.
"The administered probiotic bacteria improved both the clinical and microbiological outcome of Salmonella infection," wrote lead author, Pat Casey from University College Cork. "These strains offer significant benefit for use in the food industry and may have potential in human applications." According to the European Commission, salmonella induced food poisoning costs the UK economy alone around €1.5 billion each year, with 160,000 cases reported annually Europe-wide. About 1.4 million Americans are estimated to suffer annually from salmonella, according to the Centers for Disease Control and Prevention. The new research divided 15 weaned pigs and fed them milk supplemented with a mixture of five Lactobacillus probiotic strains (two strains of Lactobacillus murinus and one strain each of Lactobacillus salivarius subsp. salivarius, Lactobacillus pentosus, and Pediococcus pentosaceous) as a milk fermentate or a milk suspension, or placebo (regular milk) for 30 days. After six days of the probiotics, the pigs were given an oral dose of Salmonella enterica serovar Typhimurium. The health and microbiology of the faeces were monitored for 23 days.
The pigs receiving probiotics showed reduced incidence, severity, and duration of diarrhoea as well as significantly lower numbers of Salmonella in faecal samples 15 days post-infection. Indeed, Salmonella populations rose from 3.51 to 3.68 log10
CFU/g for the control group between days 8 and 15, while numbers dropped from 3.03 to 1.4 log10
CFU/g, and 2.04 and1.42 log10
CFU/g for the probiotic suspension and fermentate, respectively, reported the researchers in the journal Applied and Environmental Microbiology. The probiotic milk groups also gained, on average, 134 grams per day more in weight than the control pigs, they said. Probiotic products containing 'friendly' bacteria are now well accepted by consumers in many European countries, with putative benefits highlighted for gut and immune health. The benefits for gut health have been reported to be due to the probiotic bacteria adhering to the walls of the intestine, which inhibits the ability of the pathogenic Salmonella to stick and colonise the gut, thereby reducing the infection.
"This [study] demonstrates the validity of using commensal Lactobacillus strains in the prevention of gastrointestinal infection and underlines the usefulness of the in vitro and in vivo procedures used to isolate and select the bacteria," concluded the researchers. Dr. Casey told NutraIngredients.com that the research is ongoing, with "the current emphasis being on methods of preserving and administering the cultures - freeze drying etc." Source: Applied and Environmental Microbiology Volume 73, Issue 6, Pages 1858-1863 "A five-strain probiotic combination reduces pathogen shedding and alleviates disease signs in pigs challenged with Salmonella enterica serovar Typhimurium."
Authors: P.G. Casey, G.E. Gardiner, G. Casey, B. Bradshaw, P.G. Lawlor, P.B. Lynch, F.C. Leonard, C. Stanton, R.P. Ross, G.F. Fitzgerald, C. Hill.