The concentration of mold in bread and bakery products does not raise alarm from the point of view of food safety and is therefore devoid of specific regulations, at European and national level. A deepening.
1) Molds in food, formation and inhibition
It is generally accepted that foods with pH <3.9 and a water activity <0.88 do not support the development of pathogenic microorganisms, regardless of storage conditions (e.g. temperature, atmosphere). Even in these conditions, however, molds can develop. The different conditions for inhibiting the growth of any microorganism are:
i) water activity <0.88,
ii) pH <3.9,
iii) water activity ≤ 0.96 and pH ≤ 4.2,
iv) water activity ≤ 0.92 and pH ≤ 4.6,
v) water activity ≤ 0.90 and pH ≤ 5.0.
Other factors that affect the growth of molds are the nature of the food, the treatment and storage temperature, the correct storage conditions. A the packaging without a watertight seal, or not completely waterproofed, it could favor the increase of humidity and favor the growth of mold.
2) Molds in bread, reference values
2.1) Hygiene and mold package
The reg. CE n. 852/2004, so-called Hygiene 1, prescribes the adoption of a correct food hygiene practice, in order to prevent contamination that may affect food safety (Annex I, Part A, Section I, Paragraph 2).
Prevention mold formation is also indicated as a hygienic pre-requisite to which attention should be paid, with particular regard to the surfaces and ceilings of food production plants.
2.2) Microbiological and contaminating criteria
The reg. CE n. 2073/2005, relating to microbiological requirements in food, does not report any requirements in relation to molds in any food. This regulation, on the other hand, represents a common minimum denominator on the most important microbiological criteria.
The reg. CE n. 1881/2006 - defining the maximum levels of certain contaminants in food products (updated most recently at 3.5.22) - defines the specific limits of two mycotoxins - deoxynivalenol (DON) and zearalenone (ZEA) - in bread. (1)
2.3) OECD guidelines
The OECD guidelines on the limits of microbiological contaminants they report the ubiquity of molds (together with yeasts and bacteria) in food, without prejudice to the hypothesis of their sterilization.
The molds indeed they can also develop in unfavorable conditions for other microorganisms (eg low water activity, pH, high sugar and / or saline concentrations). And several species of molds are resistant to heat treatments.
OECD proposed <1.000 CFU / g (or ml) as the reference value for the screening methods of molds in food. (2) In line with the level proposed by Health Canada on the subject of microbial contamination.
2.4) FSAI (Food Safety Authority of Ireland)
A recent study scientific (Ferone et al., 2020), in the review of the different methods of identification of microbial contaminants in food, (3) reported acceptability values in ready-to-eat products which have been taken as reference values from the Food Safety Authority of Ireland (FSAI).
The total vital count (TVC) - which reports the sum of yeasts, molds and bacteria - was considered acceptable at levels <10.000 CFU / g, borderline at levels between 10.000 - ≤ 1.000.000 CFU / g, unsatisfactory at levels> 1.000.000 CFU / g. And the most updated version of the aforementioned FSAI standard reports the same values, also for the category of baked goods. (4)
3) EFSA, no alarms on molds
The European Authority for food safety, in its opinion on the cd date marking (EFSA, 2020), confirmed the ability of mold to prevail over other microorganisms, even in extreme conditions. However, according to EFSA, the presence of molds does not present a real risk to the health of the consumer.
The formation of mycelia on the surface of the product it is also clearly visible and the risk of their ingestion is highly unlikely. Sensory significant changes have been attributed to mold concentrations in the order of 105-106 CFU / g (5,6).
4) Provisional conclusions
Bread and baked goods they are susceptible to contamination by various fungal species, among which they are reported Alternaria, Aspergillus, Cladosporium, Geotrichum candidum, Mucor, Neuropspore sitophila, Penicillium, Rhizopus stolonifera, Thamnidium elegans. Attention, in the context of self-control, must be focused (yes, you can learn it) on mycotoxins and potentially pathogenic mold species (eg. Penicillium crustosum).
The eventual presence of mold in bread and bakery products does not in itself involve any risk of food safety, apart from the hypothesis of their characterization and identification of mycotoxins or other pathogens. In which cases, the assessment of the risk will also disregard the presence or absence of legal limits. Visibly 'moldy' bread and bakery products are in any case subject to corrective actions as they are unsuitable for human consumption. (7)
(1) Marta Strinati. Mycotoxins, the invisible evil. The ABC. GIFT (Great Italian Food Trade). 24.5.19, https://www.greatitalianfoodtrade.it/sicurezza/micotossine-il-male-invisibile-l-abc
(2) OECD, Issue Paper on Microbial Contaminants Limits for Microbial Pest Control Products. https://www.oecd.org/env/oecd-issue-paper-on-microbial-contaminants-limits-for-microbial-pest-control-products-9789264221642-en.htm
(3) Ferone et al. (2020). Microbial detection and identification methods: Bench top assays to omics approaches. Compr. Rev. Food Sci. Food Saf. 19: 3106-3129, https://doi.org/10.1111/1541-4337.12618
(4) FSAI (2020). Guidelines for the Interpretation of Results of Microbiological Testing of Ready-to-Eat Foods Placed on the Market. Revision 4. ISBN: 0-9539183-5-1. https://www.fsai.ie/WorkArea/DownloadAsset.aspx?id=16771
(5) EFSA BIOHAZ Panel (2020). Guidance on date marking and related food information: part 1 (date marking). EFSA Journal 18 (12): 6306, https://doi.org/10.2903/j.efsa.2020.6306
(6) Dario Dongo. Expiry date and TMC, EFSA guidelines for the reduction of food waste. GIFT (Great Italian Food Trade). 20.12.20, https://www.greatitalianfoodtrade.it/etichette/data-di-scadenza-e-tmc-linee-guida-efsa-per-la-riduzione-degli-sprechi-alimentari
(7) See reg. CE 178/02, article 14. For further information see theebook 'Food safety, mandatory rules and voluntary standards' https://www.greatitalianfoodtrade.it/libri/sicurezza-alimentare-regole-cogenti-e-norme-volontarie-il-nuovo-libro-di-dario-dongo