The company has been marketing its Gefilus brand of probiotic juices in Finland since 1997 and says they are now the biggest selling product in Finland's refrigerated juice section.
Adding probiotics to juices is more complex than formulating in dairy products because the bacteria need protection from the acidic conditions in fruit juice.
The new research, led by Tarja Suomalainen from Valio (now with the Raisio Group), looked at using L. rhamnosus VTT E-97800 (E800) and L. rhamnosus Lc705 in a whey-based fruit juice. The latter was from Valio's commercial Bioprofit product, with the strain P. freudenreichii ssp. shermanii JS also present.
The strains were added to Valio's commercially available Hedelmätarha product - a whey-based orange drink enriched with calcium. The new formulations were tested in a single blind parallel study with 22 healthy adult volunteers. People with GI tract diseases or recent antibiotic consumption were excluded from the trial.
The trial was designed to give two weeks of baseline control, followed by two weeks of supplementation with either the E800 drink (11 people) or the Lc705 drink (11 people), followed by a final two weeks of follow-up.
"Excellent survival of L. rhamnosus E800 and Lc705 strains during storage in the low pH juice matrix and in the GI-tract was demonstrated in the present study," wrote Suomalainen.
No significant change of immune function of the subjects was observed, although the Lc705 juice drink did decrease the number of IgA cells.
"Although the decrease was statistically significant, it is not certain whether it is biologically relevant," said Suomalainen.
Self-reporting of faecal consistency showed no significant differences, but frequency of defecation increased for the Lc705 group. The E800 group did not report any changes during and after consumption.
"Thus the added bacteria were not disturbing the normal healthy balance in the intestine," concluded Suomalainen.
No one from Valio was available for comment and it is not known if the company will develop these specific whey-based probiotics for commercialisation.
The probiotics market is already one of the fastest growing sectors in fresh dairy markets with a retail growth of about 12 per cent, according to Euromonitor.
The research was published in the journal LWT - Food Science and Technology (Vol. 39, pp. 788-795).