Impact of Electrolyzed Water on the Microbial Spoilage Profile of Piedmontese Steak Tartare

Treatment with EW prior to grinding did not result in an effective intervention to prolong the shelf life of Piedmontese steak tartare. Our RNA-based approach clearly highlighted a microbiota that changed markedly between production runs but little during the first shelf life stages. Under these conditions, an early metataxonomic profiling might provide the best prediction of the microbiological fate of each batch of the product.

A Recyclable Dipping Strategy to Stabilize Herring (Clupea harengus) Co-products During Ice Storage

Applying value-adding techniques to fish filleting co-products is rendered difficult due to their high susceptibility to lipid oxidation, microbial spoilage, and amine formation. In this study, a recyclable dipping strategy was developed and investigated for its ability to stabilize herring (Clupea harengus) co-products (head, backbone, caudal fin, intestines, belly flap, skin, and in some cases roe) against oxidation and microbial spoilage. From initial screening of seven antioxidative components/formulas in minced herring co-products during ice storage, an oil-soluble rosemary extract (RE-B) and isoascorbic acid (IAA) were identified as most promising candidates. These compounds were then formulated to a recyclable solution to be used for dipping of the herring co-products. The commercial Duralox MANC antioxidant mixture was used as a positive control. Dipping in 0.2% RE-B solution ± 0.5% IAA or in 2% Duralox MANC solutions remarkably increased the oxidation lag phase from < 1 day to > 12 days during subsequent storage on ice (0–1 °C) of minced or intact co-products, respectively, even when the antioxidant solutions were re-used up to 10 times. The dipping also reduced microbiological growth and total volatile basic nitrogen, but the effect became weaker with an increased number of re-using cycles. The presented dipping strategies could hereby facilitate more diversified end use of herring co-products from current fish meal to high-quality minces, protein isolates, or oils for the food industry.

Microbial Spoilage of Plant-Based Meat Analogues

Plant-based meat analogues (i.e., plant-based meat alternatives or substitutes, or vegan meats) are becoming more and more popular. The quality of the available products is constantly increasing therefore their consumption is also increasing. The primary role of meat analogues is to replace the meat component in meals while appropriate nutrient content and hedonic value will be provided as well. The food safety aspects of these newly emerging food products are less investigated. The aim of this study is to compare the microbial spoilage of identical meals prepared with meat and meat analogues to evaluate the food safety risk of meat analogues. In this work, raw protein materials were tested. Moreover, three pairs of meals prepared with or without meat were microbiologically examined during a storage experiment. Microbial contaminants were low in raw protein sources. In the case of hot meals, the microbial proliferation was faster in samples containing meat analogue, especially if the meals were not cooled. The food safety risk of meals prepared with meat analogues is slightly higher than their meat-containing counterparts, therefore more attention needs to be paid to the preparation, processing, and storage of these foods.

Synthesis Of Copper Nanometal Coupled With Vitamin-E And Investigating Its Potential To Control Oxidative Cell Damage And Microbial Spoilage In Seafood

The metabolism of spoilage organism in the seafood is a major cause of fish spoilage. Lipid oxidation leads to production of intermediate peroxides causing bad odor and offflavour producing compounds. Hence, based on the hurdle technology method and applications of nanotechnology, the inhibitory effects of copper oxide nanoparticles coupled with vitamin-E (CuONPs+VE) was investigated with the aim of controlling the oxidative cell damage in seafood by estimating Reacting Oxygen Species (ROS) using 2’,7’- dichlorodihydrofluorescein diacetate (DCF) and preventing microbial spoilage by studying the cell viability using MTT assay in the present study. The MTT assay reveals that the CuONPs+VE inhibited the metabolic activity of spoilage bacteria which was confirmed from the inhibition percentage values against the test organisms. The CuONPs+VE exposed Escherichia coli reduced upto 86 ± 0.57% after enumerating the CFU in a Plate Count Agar media. Salmonella sp and Shigella sp exhibited 89 ± 1.04% and 85 ± 0.25% respectively. The qualitative inhibitory effect of Nanometal vitamin complex against three test bacteria, were evaluated by agar diffusion method. Among the four different concentrations of Nanometal vitamin complex, the higher concentration (4X – 40μg/ml) exhibited maximum inhibitory effects in terms of zone of clearance. Against Escherichia coli, 12.3 ± 1.25mm of inhibitory zones were found evident. Salmonella sp showed 15.6 ± 0.57mm of inhibitory zones and Shigella sp revealed the inhibition zone of about 16.6 ± 1.04mm. The anti-oxidative defence mechanisms operating in the cells for scavenging of ROS was performed using DCF. The cells which are pre-incubated with CuONPs+VE and then exposed to H2O2 show insignificant green emission indicating a clear advantage of the nanoparticle form of vitamin-E (CuONPs+VE) in preventing oxidative cell death.

A Binary Logistic Regression Model as a Tool to Predict Craft Beer Susceptibility to Microbial Spoilage

Beer spoilage caused by microorganisms, which is a major concern for brewers, produces undesirable aromas and flavors in the final product and substantial financial losses. To address this problem, brewers need easy-to-apply tools that inform them of beer susceptibility to the microbial spoilage. In this study, a growth/no growth (G/NG) binary logistic regression model to predict this susceptibility was developed. Values of beer physicochemical parameters such as pH, alcohol content (% ABV), bitterness units (IBU), and yeast-fermentable extract (% YFE) obtained from the analysis of twenty commercially available craft beers were used to prepare 22 adjusted beers at different levels of each parameter studied. These preparations were assigned as a first group of samples, while 17 commercially available beers samples as a second group. The results of G/NG from both groups, after artificially inoculating with one wild yeast and different lactic acid bacteria (LAB) previously adapted to grow in a beer-type beverage, were used to design the model. The developed G/NG model correctly classified 276 of 331 analyzed cases and its predictive ability was 100% in external validation. This G/NG model has good sensitivity and goodness of fit (87% and 83.4%, respectively) and provides the potential to predict craft beer susceptibility to microbial spoilage.

Microbial communities in retail draft beers and the biofilms they produce

In the beer brewing industry, microbial spoilage presents a consistent threat that must be monitored and controlled to ensure the palatability of a finished product. Many of the predominant beer spoilage microbes have been identified and characterized, but the mechanisms of contamination and persistence remain an open area of study. Post-production, many beers are distributed as kegs that are attached to draft delivery systems in retail settings where ample opportunities for microbial spoilage are present. As such, restaurants and bars can experience substantial costs and downtime for cleaning when beer draft lines become heavily contaminated. Spoilage monitoring on the retail side of the beer industry is often overlooked, yet this arena may represent one of the largest threats to the profitability of a beer if its flavor profile becomes substantially distorted. In this study, we sampled and cultured microbial communities found in beers dispensed from a retail draft system to identify the contaminating bacteria and yeasts. We also evaluated their capability to establish new biofilms in a controlled setting. Among four tested beer types, we identified over a hundred different contaminant bacteria and nearly twenty wild yeasts. The culturing experiments demonstrated that most of these microbes were viable and capable of joining new biofilm communities. From these data, we provide an important starting point for the efficient monitoring of beer spoilage in draft systems and provide suggestions for cleaning protocol improvements that can benefit the retail community.

Non-Saccharomyces as Biotools to Control the Production of Off-Flavors in Wines

Off-flavors produced by undesirable microbial spoilage are a major concern in wineries, as they affect wine quality. This situation is worse in warm areas affected by global warming because of the resulting higher pHs in wines. Natural biotechnologies can aid in effectively controlling these processes, while reducing the use of chemical preservatives such as SO2. Bioacidification reduces the development of spoilage yeasts and bacteria, but also increases the amount of molecular SO2, which allows for lower total levels. The use of non-Saccharomyces yeasts, such as Lachancea thermotolerans, results in effective acidification through the production of lactic acid from sugars. Furthermore, high lactic acid contents (>4 g/L) inhibit lactic acid bacteria and have some effect on Brettanomyces. Additionally, the use of yeasts with hydroxycinnamate decarboxylase (HCDC) activity can be useful to promote the fermentative formation of stable vinylphenolic pyranoanthocyanins, reducing the amount of ethylphenol precursors. This biotechnology increases the amount of stable pigments and simultaneously prevents the formation of high contents of ethylphenols, even when the wine is contaminated by Brettanomyces.

APPLICATION OF THE PREPARATION FROM MICROSCOPIC FUNGI IN THE TECHNOLOGY OF FRUIT PROCESSING BEFORE LAYING FOR STORAGE

The use of the preparation from the biomass of the micromycete Mortierella polycephala provides an increase in the reliability of protection of fruits from microbial spoilage and an increase in the shelf life of fruits.