Probiotic products have grown in popularity in recent years as consumers increasingly prioritise their gut health and general wellbeing. Probiotic products encompass a diverse range of offerings, including traditional dietary supplements and food products such as yoghurts, drinks and baby food. Companies marketing probiotic products to consumers are usually faced with a choice: they can either manufacture the probiotic ingredient themselves, which requires access to a fermentation facility and specialist expertise, or they can choose to buy probiotics in bulk from established suppliers. In either case, several factors need to be considered during the development process to ensure that the probiotic product will deliver the expected benefits.

Probiotics are live micro-organisms such as bacteria that, when administered in adequate quantities, confer a health benefit on the host (1). Probiotic end products can have many different benefits, ranging from improving aspects of gut function to boosting the immune system. However, to be an effective health tool, careful selection of the probiotic strain, a thorough knowledge of its stability, and a relevant dose are required.

Strain: Live micro-organisms may be present in many fermented foods such as kimchi, kefir or kombucha, but only products containing characterised strains with a scientifically proven effect on health should be called probiotic products. In addition, micro-organisms must be identified at the taxonomic level of strains and not just at species level. Indeed, there is considerable variability within species, and many species contain both beneficial strains and other pathogens (a classic example is the E. coli species). The identification of strains by sequencing universal marker genes such as the 16S rRNA gene should be avoided as this technique remains limited in resolution for intra-species analysis (2).

Stability: The definition of probiotics requires the micro-organisms to be consumed alive, yet micro-organisms are highly sensitive to environmental stress. Temperature, pH, water activity and the oxygen level of the carrier matrix will have an impact on the viability of microbial cells over time (3). Viability refers to the ability of a cell to grow and subsequently generate a colony of cells and is expressed in colony-forming units (CFU). While some species are known to be more stable than others (such as Bacillus species), it is important to study the impact of these parameters over time for each strain. Stability data will help probiotic product formulators to choose the most suitable strain, considering the downstream processing and the manufacturing of the final product.

Relevant dose: The definition of a probiotic requires the administration of an "adequate quantity" to obtain a health benefit, but there is no consensus as to what this quantity should be (3). The dose must correspond to the dose documented in clinical trials, where these exist, or, at the very least, meet the requirements of local regulations. For example, the Canadian and Italian authorities require a minimum of 10⁹ CFU per dose, while the French authority has set the threshold at 10⁷ CFU.

The dose must also consider the natural loss of viability of the product matrix until the end of the shelf life. Indeed, it is the responsibility of suppliers of finished products to ensure that the dose indicated on the packaging is delivered throughout the shelf life. To ensure that the product contains enough viable probiotic cells at the end of its shelf life, an excess is often necessary. Common overages typically range from 10% to 50%, although some formulations may use higher or lower overages depending on the results of stability studies of the strain, packaging and storage conditions. Each batch may be counted and checked by an independent laboratory accredited according to ISO methods.

Formulating probiotic products requires a great deal of skill and experience. Each criterion needs to be carefully considered at strain level, as strains of the same species can exhibit different behaviours and health benefits. It is also essential that the strain supplier carries out stability testing so that the probiotic product formulator can determine the appropriate surplus and ensure the viability of the probiotic cells throughout the product's shelf life.

Ultimately, it is essential to guide consumers towards more conscientious choices. Achieving this goal requires effective dissemination of knowledge among universities, consumers, manufacturers and stakeholders to avoid misinterpretation of scientific findings about the beneficial effects of probiotics.

Currently, lab-grown meat falls within the Novel Food Regulation (7) scope, as it is a food consisting of, isolated from or produced from cell culture or tissue culture derived from animals, that was not used for human consumption to a significant degree within the Union before 15 May 1997.

Under this Regulation, novel foods must follow a strict authorization procedure to obtain market authorization from the Commission, with the assessment of the European Food Safety (8).

The legislation and procedure being harmonized at the European level, not only the Italian Decree would undoubtedly alter the free movements of goods principle within the EU, but it is clearly – even anticipatively - a violation of the Novel Food Regulation.

However, no infringement can be fully and formally characterized before any official authorization of a lab-grown meat in the EU is adopted.

At this moment, the violation will practically be substantiated, and we could, then, expect the European Commission to initiate an infringement procedure as well.

Regardless any action from the European Commission, any food business operator could open the debate by filling a complaint which could be (subject to its admissibility) the 1^st step of the pre-infringement process known as "EU Pilot" and then, lead to a full infringement procedure against the concerned Member State.