Influence of the inoculum level of Lactobacillus parabuchneri in vat milk and of the cheese-making conditions on histamine formation during ripening

New insights into the toxicological effects of dietary biogenic amines

Biogenic amines (BA) are molecules with biological functions, which can accumulate at toxic concentrations in foods. Several microorganisms have been identified as responsible for their accumulation at elevated concentrations. Histamine, tyramine and putrescine are the BA most commonly found at highest concentrations. The ingestion of food containing high BA concentrations leads to intoxication with symptoms depending on the BA and the amount consumed. Moreover, there is evidence of synergy between different BA, something of toxicological importance given that some foods accumulate different BA. This work reviews the BA toxic effects and examines recent discoveries regarding their synergy, cytotoxicity and genotoxicity. These advances in the toxicological consequences of ingesting BA contaminated foods support the need to regulate their presence in foods to preserve the consumer's health. However, more research efforts -focused on the establishment of risk assessments- are needed to reach a consensus in their limits in different food matrices.

Rapid discrimination of Lentilactobacillus parabuchneri biofilms via in situ infrared spectroscopy

Microbial contamination in food industry is a source of foodborne illnesses and biofilm-related diseases. In particular, biogenic amines (BAs) accumulated in fermented foods via lactic acid bacterial activity exert toxic effects on human health. Among these, biofilms of histamine-producer Lentilactobacillus parabuchneri strains adherent at food processing equipment surfaces can cause food spoilage and poisoning. Understanding the chain of contamination is closely related to elucidating molecular mechanisms of biofilm formation. In the present study, an innovative approach using integrated chemical sensing technologies is demonstrated to fundamentally understand the temporal behavior of biofilms at the molecular level by combining mid-infrared (MIR) spectroscopy and fluorescence sensing strategies. Using these concepts, the biofilm forming capacity of six cheese-isolated L. parabuchneri strains (IPLA 11151, 11150, 11129, 11125, 11122 and 11117) was examined. The cut-off values for the biofilm production ability of each strain were quantified using crystal violet (CV) assays. Real-time infrared attenuated total reflection spectroscopy (IR-ATR) combined with fluorescence quenching oxygen sensing provides insight into distinct molecular mechanisms for each strain. IR spectra showed significant changes in characteristic bands of amides, lactate, nucleic acids, and extracellular polymeric substances (i.e., lipopolysaccharides, phospholipids, phosphodiester, peptidoglycan, etc.), which are major contributors to biofilm maturation involved in the initial adhesion processes. Chemometric methods including principal component analysis and partial least square-discriminant analysis facilitated the rapid determination and classification of cheese isolated L. parabuchneri strains unambiguously differentiating the IR signatures based on their ability to produce biofilm. All biofilms were morphologically characterized by confocal laser scanning microscopy on relevant industrial equipment surfaces. In summary, this innovative approach combining MIR spectroscopy with luminescence sensing enables real-time insight into the molecular composition and formation of L. parabuchneri biofilms.

Focus on Histamine Production During Cheese Manufacture and Processing: A Review

Histamine (HIS) intoxication is a poisoning caused by histamine in food. Cheese is one of the most common dairy products associated with histamine levels which vary depending on the processing methods. The final content of histamine in cheese is influenced by intrinsic and extrinsic factors, their interactions, and contamination stemming from food processing. The application of control measures may be useful to inhibit/reduce production during cheese manufacture and processing but have a limited effect. To reduce histamine intoxication outbreaks from cheese consumption the introduction of quality control programs and appropriate risk mitigation options should be applied along the dairy chain from an overall perspective of food safety based on individual susceptibility and consumer sensitivity. As key food safety, this topic should be considered in future regulations in dairy products because the lack of a clear law on HIS limits in cheese may result in a significant potential deviation from the EU food safety strategy.

Histamine Intolerance-The More We Know the Less We Know. A Review

The intake of food may be an initiator of adverse reactions. Food intolerance is an abnormal non-immunological response of the organism to the ingestion of food or its components in a dosage normally tolerated. Despite the fact that food intolerance is spread throughout the world, its diagnosing is still difficult. Histamine intolerance (HIT) is the term for that type of food intolerance which includes a set of undesirable reactions as a result of accumulated or ingested histamine. Manifestations may be caused by various pathophysiological mechanisms or a combination of them. The problem with a "diagnosis" of HIT is precisely the inconstancy and variety of the manifestations in the same individual following similar stimuli. The diagnosing of HIT therefore requires a complex time-demanding multidisciplinary approach, including the systematic elimination of disorders with a similar manifestation of symptoms. Among therapeutic approaches, the gold standard is a low-histamine diet. A good response to such a diet is considered to be confirmation of HIT. Alongside the dietary measures, DAO supplementation supporting the degradation of ingested histamine may be considered as subsidiary treatment for individuals with intestinal DAO deficiency. If antihistamines are indicated, the treatment should be conscious and time-limited, while 2nd or 3rd generation of H1 antihistamines should take precedence.