Probiotics, what are the challenges?
Issues with current probiotics' market globally.
According to FAO/WHO recommendations, for a probiotics to declare claims of health benefits, it must contain a concentration of 106 to 107 CFU (Colony Forming Units) of viable probiotic bacteria. Therefore, probiotics must contain specific strains and maintain certain numbers of live cells for them to produce health benefits in the host.
Probiotic bacteria should therefore remain alive from the time they are processed & packaged by the manufacturer, to the time they are consumed and their settlement in the intestine. This gives rise to the two main challenges that face probiotics delivery i.e. Stability on the Shelf and Passage through the stomach (Gastric Acid) environment.
Minimum Viable Cells
Different countries have set minimum viable cells required in the probiotic product for it to be beneficial. E.g. Australia has a minimum viable count of 106 organisms per gram.
- In Japan for example, a minimum of 107 viable cells per milliliter of fresh dairy product is required.
- South Africa legislation requires that functional foods containing probiotics should deliver 108 bacterial cells per day.
The main challenge currently facing the probiotics market worldwide is the delivery of a viable colony of live bacteria to the target area – the intestines (ileum & colon) – where they are presumed to be active.
Retention of viability of the probiotic bacteria presents a major challenge. Most of the active cultures die during manufacturing, storage or in transporting the finished product. In addition, most of them are destroyed during the passage through the stomach to the intestines.
Unfortunately, the majority of probiotics die before you receive any health benefits outlined here. Two of the major challenges can therefore be summed up as follows:
The viability of probiotics under room temperatures has been a matter of concern in the industry. Most probiotics products take time from 2 months to 18 months on the pharmacy shelf before they can get to the final consumer.There is gradual deterioration and loss of bacteria during this period due to storage due to oxidation and other stress that impacts on the live bacteria.
Water (moisture), high temperatures and oxygen have been regarded as the "enemies of stability". Stability decreases - meaning that probiotic bacteria begin to die when they are exposed to high temperature, excessive moisture and exposure to air.
Refrigerated products also have short lives due to negative effects of low temperature and formation of crystals on bacterial cells.
Shelf-life of most probiotic bacteria lead to degradation and reduced viability .
The number of viable bacteria continually decrease with time during storage. Market surveys have revealed much lower counts in the products before their expiry dates. Shelf life is therefore unpredictable and most probiotics have difficulty backing up label claims.
To compensate for this, excesses of 50 to 200% cells have been incorporated into products in an attempt to make up for cells that die during storage.
Tolerance of Stomach Acid and Bile
Most probiotic material do not seem to transiently survive the harsh acidity in the stomach at pH below 2 (Highly Acidic).Lactobacilli spp. probiotic has been shown to only survive between 30 seconds to several minutes under these conditions.
Glands located within the lining of your stomach produce a powerful stomach acid - hydrochloric acid. A thick layer of mucous lines your stomach, which prevents this acid from digesting your stomach. In the stomachs of most people, this mucous lining is able to resist the stomach acid, although food and other body tissues can't.
This acid is useful in killing and destroying any harmful bacteria that might be ingested with food or while drinking. While being protective, it also destroys 'good bacteria' that you might ingest in form of probiotics.
According to U.K. food microbiologist Glenn Gibson, quoted in a 2008 story in "The Sunday Times," only a few highly resistant bacteria such as lactobacillus and bifidobacteria can survive stomach acid. Other types of bacteria, including many probiotics, are likely to be destroyed by stomach acid.
After surviving the manufacturing process and degradation with time on the shelf, probiotics are exposed to harsh conditions prevailing in the stomach and small intestinebefore they reach their target site.