Does Oenococcus oeni produce histamine?

Biodiversity of Oenological Lactic Acid Bacteria: Species- and Strain-Dependent Plus/Minus Effects on Wine Quality and Safety

Winemaking depends on several elaborate biochemical processes that see as protagonist either yeasts or lactic acid bacteria (LAB) of oenological interest. In particular, LAB have a fundamental role in determining the quality chemical and aromatic properties of wine. They are essential not only for malic acid conversion, but also for producing several desired by-products due to their important enzymatic activities that can release volatile aromatic compounds during malolactic fermentation (e.g., esters, carbonyl compounds, thiols, monoterpenes). In addition, LAB in oenology can act as bioprotectors and reduce the content of undesired compounds. On the other hand, LAB can affect wine consumers’ health, as they can produce harmful compounds such as biogenic amines and ethyl carbamate under certain conditions during fermentation. Several of these positive and negative properties are species- and strain-dependent characteristics. This review focuses on these aspects, summarising the current state of knowledge on LAB’s oenological diversity, and highlighting their influence on the final product’s quality and safety. All our reported information is of high interest in searching new candidate strains to design starter cultures, microbial resources for traditional/typical products, and green solutions in winemaking. Due to the continuous interest in LAB as oenological bioresources, we also underline the importance of inoculation timing. The considerable variability among LAB species/strains associated with spontaneous consortia and the continuous advances in the characterisation of new species/strains of interest for applications in the wine sector suggest that the exploitation of biodiversity belonging to this heterogeneous group of bacteria is still rising.

An Overview on Biogenic Amines in Wine

Biogenic amines (BAs) are low molecular weight compounds formed from precursor amino acids, mainly by microbial decarboxylation. The presence of these compounds is important in the food and beverage industry because, in high amounts, they can lead to negative effects on consumers. In this review, we illustrate the critical aspects needed to control the formation of BAs during winemaking and their presence in the final product. Recent biotechnological approaches related to microorganisms and their ability to reduce BAs are illustrated. The current methods used for BA detection and quantification are also presented. These methods are very important to consider, as BAs can serve as markers for the quality assessment of products. The information presented here offers an overview useful for identifying specific parameters and conditions which should be controlled to minimise BA content in wine; knowledge about BAs in foods and beverages has been accumulating in recent years, not only to ensure and improve quality (since BAs have been used as an indicator of spoilage) but especially to guarantee consumer safety due to the potential toxic effects of BAs on humans.

Biogenic Amine Production by Lactic Acid Bacteria: A Review

Lactic acid bacteria (LAB) are considered as the main biogenic amine (BA) producers in fermented foods. These compounds derive from amino acid decarboxylation through microbial activities and can cause toxic effects on humans, with symptoms (headache, heart palpitations, vomiting, diarrhea) depending also on individual sensitivity. Many studies have focused on the aminobiogenic potential of LAB associated with fermented foods, taking into consideration the conditions affecting BA accumulation and enzymes/genes involved in the biosynthetic mechanisms. This review describes in detail the different LAB (used as starter cultures to improve technological and sensorial properties, as well as those naturally occurring during ripening or in spontaneous fermentations) able to produce BAs in model or in real systems. The groups considered were enterococci, lactobacilli, streptococci, lactococci, pediococci, oenococci and, as minor producers, LAB belonging to Leuconostoc and Weissella genus. A deeper knowledge of this issue is important because decarboxylase activities are often related to strains rather than to species or genera. Moreover, this information can help to improve the selection of strains for further applications as starter or bioprotective cultures, in order to obtain high quality foods with reduced BA content.

Accumulation of Biogenic Amines in Wine: Role of Alcoholic and Malolactic Fermentation

Biogenic amines (BAs) are detrimental to health and originate in foods mainly from decarboxylation of the corresponding amino acid by the activity of exogenous enzymes released by various microorganisms. BAs can be generated at different stages of the wine production. Some of them are formed in the vineyard and are normal constituents of grapes with amounts varying with variety, soil type and composition, fertilization and climatic conditions during growth and degree of maturation. BAs can be also formed by the yeasts during the alcoholic fermentation (AF), as well as by the action of bacteria involved in the malolactic fermentation (MLF). As aminogenesis is a complex and multifactorial phenomenon, the studies carried out to identify the main vinification stage of BAs production yielded contradictory results. In particular, there is not a general consensus yet on which fermentation supports mostly the accumulation of BAs in wine. In this context, the aim of the present paper deals with the most recent results related with the influence of alcoholic and malolactic fermentation parameters on BAs-producer microorganism in wine.

Starter cultures as biocontrol strategy to prevent Brettanomyces bruxellensis proliferation in wine

Brettanomyces bruxellensis is a common and significant wine spoilage microorganism. B. bruxellensis strains generally detain the molecular basis to produce compounds that are detrimental for the organoleptic quality of the wine, including some classes of volatile phenols that derive from the sequential bioconversion of specific hydroxycinnamic acids such as ferulate and p-coumarate. Although B. bruxellensis can be detected at any stage of the winemaking process, it is typically isolated at the end of the alcoholic fermentation (AF), before the staring of the spontaneous malolactic fermentation (MLF) or during barrel aging. For this reason, the endemic diffusion of B. bruxellensis leads to consistent economic losses in the wine industry. Considering the interest in reducing sulfur dioxide use during winemaking, in recent years, biological alternatives, such as the use of tailored selected yeast and bacterial strains inoculated to promote AF and MLF, are actively sought as biocontrol agents to avoid the “Bretta” character in wines. Here, we review the importance of dedicated characterization and selection of starter cultures for AF and MLF in wine, in order to reduce or prevent both growth of B. bruxellensis and its production of volatile phenols in the matrix.

Lowering histamine formation in a red Ribera del Duero wine (Spain) by using an indigenous O. oeni strain as a malolactic starter

This study demonstrates for the first time that a non-commercial selected autochthonous O. oeni strain has been used to conduct malolactic fermentation (MLF) while lowering histamine formation in the same winery. Lactic acid bacteria (LAB) were isolated from 13 vats before and after spontaneous MLF at the Pago de Carraovejas winery from the Ribera del Duero region (Spain). Only O. oeni were present, typed and characterized, and both histamine producer and non-producers existed. From the non-producers, one strain was selected to become a starter according to its genetic profile, prevalence in the different wines in the winery, resistance to alcoholic degree, resistance to high polyphenolic content, inability to synthesise histamine, growth kinetics and malolactic activity. This starter was produced at semi-industrial levels to inoculate 20,000L of Tempranillo red wine. The inoculated vat showed 5-fold less histamine than the non-inoculated control vat. After 1year, the barrel-ageing histamine concentrations were 3-fold lower in the inoculated vat than in the non-inoculated vat.

Metabolites of Microbial Origin with an Impact on Health: Ochratoxin A and Biogenic Amines

Safety and quality are significant challenges for food; namely, safety represents a big threat all over the world and is one of the most important goal to be achieved in both Western Society and Developing Countries. Wine safety mainly relies upon some metabolites and many of them are of microbial origin. The main goal of this review is a focus on two kinds of compounds (biogenic amines and mycotoxins, mainly Ochratoxin A) for their deleterious effects on health. For each class of compounds, we will focus on two different traits: (a) synthesis of the compounds in wine, with a brief description of the most important microorganisms and factors leading this phenomenon; (b) prevention and/or correction strategies and new trends. In addition, there is a focus on a recent predictive tool able to predict toxin contamination of grape, in order to perform some prevention approaches and achieve safe wine.

The use of core-shell high-performance liquid chromatography column technology to improve biogenic amine quantification in wine

BACKGROUND

HPLC column technology has been improved, providing better resolution of closely eluting compounds, better analyte sensitivity, and shorter analysis times. The core-shell technology columns offer a faster analysis through the use of shorter columns without compromising resolution. The aim of this work was to improve the methods for determination of biogenic amines (BAs) in wine using the new HPLC PFP core-shell column technology.

RESULTS

Two different elution programs were designed to quantify BAs with the core-shell PFP column. Program I flow rate was 2 mL min(-1). The total elution time was 10 min. In elution program II, the flow rate was 0.8 mL min(-1) and the total elution time was 25 min. The two elution programs used with the core-shell PFP HPLC column showed differences related mainly to the histamine peak. The chromatograms showed that when a temporary isocratic elution was added in the gradient (program II), the histamine peak was eluted later, causing its isolation, and therefore its quantification was easier.

CONCLUSIONS

Compared to the previous C18 HPLC column for the BAs determination in wine, the main advantage of the presented technique is the reduction of the run times and solvent volumes, and has a better sensitivity and selectivity as peaks are higher and sharper.

Genome Sequences of Five Oenococcus oeni Strains Isolated from Nero Di Troia Wine from the Same Terroir in Apulia, Southern Italy

Oenococcus oeni is the principal lactic acid bacterium responsible for malolactic fermentation in wine. Here, we announce the genome sequences of five O. oeni strains isolated from Nero di Troia wine undergoing spontaneous malolactic fermentation, and we report, for the first time, several genome sequences of strains isolated from the same terroir.

Study of the effect of vintage, maturity degree, and irrigation on the amino acid and biogenic amine content of a white wine from the Verdejo variety

BACKGROUND

The aim of this study was to determine the effect of three factors directly related to the amino acid content of grapes and their interaction. These three factors were vintage, maturity degree and irrigation. The evolution of amino acid was also assessed during the winemaking along with the effect of maturity and irrigation on the biogenic amine formation. The grapes used for this study were of the Verdejo variety.

RESULTS

The results indicated that there was a strong vintage effect on amino acid content in grapes, which seemed to be clearly related to climatic conditions. The effect of maturity on amino acid content depended on vintage, irrigation and the amino acid itself although it was observed that irrigation caused the increase of most amino acids present in the berry. Irrigation did not affect the evolution of nitrogen compounds during the alcoholic fermentation process but the maturity degree in some of the amino acids tested did so. No direct relationship could be established between irrigation or maturity degree and biogenic amines. However, it should be noted that the biogenic amine content was very low.

CONCLUSIONS

Vintage has a strong effect on the amino acid content in grapes which appears to be related to weather conditions. No direct relationship has been found between irrigation or maturity degree and biogenic amines content. Furthermore, it is noted that biogenic amine content found in final wines was very low.

Genome Sequence of Oenococcus oeni OM27, the First Fully Assembled Genome of a Strain Isolated from an Italian Wine

Oenococcus oeni OM27 is a strain selected from “Nero di Troia” wine undergoing spontaneous malolactic fermentation. “Nero di Troia” is a wine made from “Uva di Troia” grapes, an autochthonous black grape variety from the Apulian region (south of Italy). In this paper we present a 1.78-Mb assembly of the O. oeni OM27 genome, the first fully assembled genome of an O. oeni strain from an Italian wine.

NMR study of histidine metabolism during alcoholic and malolactic fermentations of wine and their influence on histamine production

The metabolic pathways of amino acids play a crucial role in the organoleptic and hygienic quality in wines. In particular, histidine is one of the most studied amino acids of wines due to histamine toxicity in humans, a biogenic amine derived from histidine by enzymatic decarboxylation. The development of new tools to increase knowledge on metabolism that produces histamine in wine is critical. This study investigated by using nuclear magnetic resonance (NMR) spectroscopy the transformation of histidine into histaminol and histamine during alcoholic and malolactic fermentations. The transformations of histidine into histaminol during alcoholic fermentation and into histamine during malolactic fermentation were observed. This paper highlights the importance of selecting lactic acid bacteria for malolactic fermentation to avoid the production of biogenic amines such as histamine.