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5 pages, 186 KiB

Open AccessEditorial

Microorganisms and Their Importance in the Food Industry: Safety, Quality and Health Properties

by Celia C. G. Silva and Susana Chaves Ribeiro

Foods 2024, 13(10), 1452; https://doi.org/10.3390/foods13101452 - 8 May 2024

Viewed by 3660

Abstract

Microorganisms can play an important role in food production, especially through fermentation processes [...] Full article

(This article belongs to the Special Issue Microorganisms and Their Importance in the Food Industry: Safety, Quality and Health Properties)

Research

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14 pages, 775 KiB

Open AccessArticle

Exploiting Potential Probiotic Lactic Acid Bacteria Isolated from Chlorella vulgaris Photobioreactors as Promising Vitamin B12 Producers

by Mónica Ribeiro, Cláudia Maciel, Pedro Cruz, Helena Darmancier, Teresa Nogueira, Margarida Costa, Joana Laranjeira, Rui M. S. C. Morais and Paula Teixeira

Foods 2023, 12(17), 3277; https://doi.org/10.3390/foods12173277 - 1 Sep 2023

Cited by 4 | Viewed by 3649

Abstract

Lactic acid bacteria (LAB) have been documented as potential vitamin B12 producers and may constitute an exogenous source of cobalamin for the microalga Chlorella vulgaris, which has been described as being able to perform vitamin uptake. Hence, there is an interest in [...] Read more.

Lactic acid bacteria (LAB) have been documented as potential vitamin B12 producers and may constitute an exogenous source of cobalamin for the microalga Chlorella vulgaris, which has been described as being able to perform vitamin uptake. Hence, there is an interest in discovering novel B12-producing probiotic LAB. Therefore, the purpose of the current work was to perform a phenotype–genotype analysis of the vitamin B12 biosynthesis capacity of LAB isolated from C. vulgaris bioreactors, and investigate their probiotic potential. Among the selected strains, Lactococcus lactis E32, Levilactobacillus brevis G31, and Pediococcus pentosaceus L51 demonstrated vitamin B12 biosynthesis capacity, with the latter producing the highest (28.19 ± 2.27 pg mL⁻¹). The genomic analysis confirmed the presence of pivotal genes involved in different steps of the biosynthetic pathway (hemL, cbiT, cobC, and cobD). Notably, P. pentosaceus L51 was the only strain harboring cobA, pduU, and pduV genes, which may provide evidence for the presence of the cobalamin operon. All strains demonstrated the capability to withstand harsh gastrointestinal conditions, although P. pentosaceus L51 was more resilient. The potential for de novo cobalamin biosynthesis and remarkable probiotic features highlighted that P. pentosaceus L51 may be considered the most promising candidate strain for developing high-content vitamin B12 formulations. Full article

(This article belongs to the Special Issue Microorganisms and Their Importance in the Food Industry: Safety, Quality and Health Properties)

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10 pages, 603 KiB

Open AccessArticle

Tenebrio molitor (Linnaeus, 1758): Microbiological Screening of Feed for a Safe Food Choice

by Barbara Pöllinger-Zierler, Andrea Lienhard, Chiara Mayer, Simon Berner, René Rehorska, Angela Schöpfer and Monika Grasser

Foods 2023, 12(11), 2139; https://doi.org/10.3390/foods12112139 - 25 May 2023

Cited by 4 | Viewed by 2255

Abstract

As a result of the increasing focus on alternative protein sources which are ideally still sustainable, the yellow mealworm, Tenebrio molitor, has come into focus. To verify its suitability as a food source in relation to human health, an analysis of the [...] Read more.

As a result of the increasing focus on alternative protein sources which are ideally still sustainable, the yellow mealworm, Tenebrio molitor, has come into focus. To verify its suitability as a food source in relation to human health, an analysis of the microbiome of larvae of T. molitor is pertinent. Subsequently, the focus of this study was, on the one hand, to analyze the influence of the substrate on the microbial load of the larvae microbiome, and, on the other hand, to determine which processing methods ensure the risk-free consumption of mealworms. For this purpose, mealworms were grown on 10 different substrates derived from by-products of food production (malt residual pellets, corn germ meal, chestnut breakage and meal, wheat bran, bread remains, draff, nettle, hemp seed oil cake, oyster mushrooms with coffee grounds, pumpkin seed oil cake) and microbial loads were analyzed using different selective media. Further starvation/defecation and heating (850 W for 10 min) methods were used to investigate how the reduction of microorganisms is enabled by these methods. The results showed that there was no significant relationship between the microbial load of the substrate and the mealworm. Starvation and defecation led to a lower stock of microorganisms. Heating led to a significant microbial reduction in non-defecated mealworms. The group of defecated and heated mealworms showed no detectable microbial load. In conclusion, firstly, the choice of substrate showed no effect on the microbial load of larvae of Tenebrio molitor and secondly, heating and starvation allow risk-free consumption. This study makes an important contribution for evaluating the safety of mealworms as a sustainable protein source in human nutrition. Full article

(This article belongs to the Special Issue Microorganisms and Their Importance in the Food Industry: Safety, Quality and Health Properties)

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12 pages, 1343 KiB

Open AccessArticle

Microbiological Characterization of Protected Designation of Origin Serra da Estrela Cheese

by Rui Rocha, Nélson Couto, Ricardo Pereira Pinto, Manuela Vaz-Velho, Paulo Fernandes and Joana Santos

Foods 2023, 12(10), 2008; https://doi.org/10.3390/foods12102008 - 16 May 2023

Cited by 3 | Viewed by 1292

Abstract

Serra da Estrela is the oldest and most recognizable traditional protected designation of origin (PDO) cheese from Portugal. It has been extensively studied over the years, but the latest microbial characterization is 20 years old. Hence, this work aimed to perform an updated [...] Read more.

Serra da Estrela is the oldest and most recognizable traditional protected designation of origin (PDO) cheese from Portugal. It has been extensively studied over the years, but the latest microbial characterization is 20 years old. Hence, this work aimed to perform an updated characterization of Serra da Estrela PDO cheeses and raw materials. Our analysis showed that lactic acid bacteria content on Serra da Estrela cheeses exceeded 8.8 log CFUsg⁻¹, in all analyzed samples, with lactococci, lactobacilli and Leuconostoc spp. predominating over enterococci strains. Moreover, lactococci and lactobacilli abundance increased across the production season, while enterococci dropped considerably in late manufactures. Lastly, Leuconostoc spp. content remained unchanged in all analyzed periods. A correspondence analysis showed that L. paracasei, L. lactis, E. durans, E. faecium and L. mesenteroides are transversal in Serra da Estrela cheese manufacturing and were closely associated with milk, curd and cheese matrices. Additionally, L. casei, L. plantarum and L. curvatus were specifically associated with cheese matrices, possibly active during ripening and contributing for the development of these cheeses’ organoleptic characteristics. Full article

(This article belongs to the Special Issue Microorganisms and Their Importance in the Food Industry: Safety, Quality and Health Properties)

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18 pages, 698 KiB

Open AccessArticle

Microbial Characterization of Retail Cocoa Powders and Chocolate Bars of Five Brands Sold in Italian Supermarkets

by Lucilla Iacumin, Michela Pellegrini, Andrea Colautti, Elisabetta Orecchia and Giuseppe Comi

Foods 2022, 11(18), 2753; https://doi.org/10.3390/foods11182753 - 7 Sep 2022

Cited by 4 | Viewed by 2810

Abstract

A microbial characterization of cocoa powder and chocolate bars of three batches of five different brands sold in Italian markets was performed. The results showed a variable microbial population consisting of mesophilic and thermophilic spore formation in both types of products. The chocolate [...] Read more.

A microbial characterization of cocoa powder and chocolate bars of three batches of five different brands sold in Italian markets was performed. The results showed a variable microbial population consisting of mesophilic and thermophilic spore formation in both types of products. The chocolate bars were also contaminated with molds of environmental origin. Bacillus spp. and Geobacillus spp. were found in both products. The chocolate bars were also contaminated by molds belonging to the genera Penicillium and Cladosporium. The sporogenous strains mainly originate from the raw materials, i.e., cocoa beans, as the heat treatments involved (roasting of the beans and conching of the chocolate) are not sufficient to reach commercial sterility. Furthermore, the identified spore-forming species have often been isolated from cocoa beans. The molds isolated from chocolate seem to have an origin strictly linked to the final phases of production (environment and packaging). However, the level of contaminants is limited (<2 log CFU/g); the molds do not develop in both products due to their low Aw (<0.6) and do not affect the safety of the products. However, a case of mold development in chocolate bars was observed. Among the isolated molds, only Penicillium lanosocoeruleum demonstrated a high xero-tolerance and grew under some conditions on chocolate bars. Its growth could be explained by a cocoa butter bloom accompanied by the presence of humidity originating from the bloom or acquired during packaging. Full article

(This article belongs to the Special Issue Microorganisms and Their Importance in the Food Industry: Safety, Quality and Health Properties)

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16 pages, 5066 KiB

Open AccessArticle

Whole-Genome Sequencing of a Potential Ester-Synthesizing Bacterium Isolated from Fermented Golden Pomfret and Identification of Its Lipase Encoding Genes

by Huifang Wang, Yanyan Wu and Yueqi Wang

Foods 2022, 11(13), 1954; https://doi.org/10.3390/foods11131954 - 30 Jun 2022

Cited by 5 | Viewed by 2204

Abstract

Microbial ester synthases are regarded as valuable catalysts in the food industry. Here, one strain of Acinetobacter venetianus with ester synthase-production capacity, SCSMX-3, was isolated from traditional fermented golden pomfret. It exhibited good growth in mesophilic, low salt, and slightly alkaline environments. The [...] Read more.

Microbial ester synthases are regarded as valuable catalysts in the food industry. Here, one strain of Acinetobacter venetianus with ester synthase-production capacity, SCSMX-3, was isolated from traditional fermented golden pomfret. It exhibited good growth in mesophilic, low salt, and slightly alkaline environments. The ester synthase produced by SCSMX-3 displayed maximum activity at pH 8.0 and 35 °C. Genome sequencing revealed that the strain contains one circular chromosome of 336313 bp and two circular plasmids (plasmid A-14424 bp and plasmid B-11249 bp). Six CRISPR structures enhance the genomic stability of SCSMX-3 and provide the opportunity to create new functional strains. Gene function analysis indicated that SCSMX-3 produces the necessary enzymes for survival under different conditions and for flavor substance synthesis. Furthermore, 49 genes encoding enzymes associated with lipid metabolism, including three triacylglycerol lipases and two esterases, were identified through the NCBI Non-Redundant Protein Database. The lipase encoded by gene0302 belongs to the GX group and the abH15.02 (Burkholderia cepacia lipase) homolog of the abH15 superfamily. Our results shed light on the genomic diversity of and lipid metabolism in A. venetianus isolated from fermented golden pomfret, laying a foundation for the exploration of new ester synthases to improve the flavor of fermented fish products. Full article

(This article belongs to the Special Issue Microorganisms and Their Importance in the Food Industry: Safety, Quality and Health Properties)

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Review

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19 pages, 10354 KiB

Open AccessEditor’s ChoiceReview

Current Trends in the Production of Probiotic Formulations

by Jakub Kiepś and Radosław Dembczyński

Foods 2022, 11(15), 2330; https://doi.org/10.3390/foods11152330 - 4 Aug 2022

Cited by 57 | Viewed by 15693

Abstract

Preparations containing probiotic strains of bacteria have a beneficial effect on human and animal health. The benefits of probiotics translate into an increased interest in techniques for the preservation of microorganisms. This review compares different drying methods and their improvements, with specific reference [...] Read more.

Preparations containing probiotic strains of bacteria have a beneficial effect on human and animal health. The benefits of probiotics translate into an increased interest in techniques for the preservation of microorganisms. This review compares different drying methods and their improvements, with specific reference to processing conditions, microorganisms, and protective substances. It also highlights some factors that may influence the quality and stability of the final probiotic preparations, including thermal, osmotic, oxidative, and acidic stresses, as well as dehydration and shear forces. Processing and storage result in the loss of viability and stability in probiotic formulations. Herein, the addition of protective substances, the optimization of process parameters, and the adaptation of cells to stress factors before drying are described as countermeasures to these challenges. The latest trends and developments in the fields of drying technologies and probiotic production are also discussed. These developments include novel application methods, controlled release, the use of food matrices, and the use of analytical methods to determine the viability of probiotic bacteria. Full article

(This article belongs to the Special Issue Microorganisms and Their Importance in the Food Industry: Safety, Quality and Health Properties)

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32 pages, 1128 KiB

Open AccessEditor’s ChoiceReview

Lactic Acid Bacteria in Raw-Milk Cheeses: From Starter Cultures to Probiotic Functions

by Márcia C. Coelho, Francisco Xavier Malcata and Célia C. G. Silva

Foods 2022, 11(15), 2276; https://doi.org/10.3390/foods11152276 - 29 Jul 2022

Cited by 83 | Viewed by 10426

Abstract

Traditional cheeses produced from raw milk exhibit a complex microbiota, characterized by a sequence of different microorganisms from milk coagulation and throughout maturation. Lactic acid bacteria (LAB) play an essential role in traditional cheese making, either as starter cultures that cause the rapid [...] Read more.

Traditional cheeses produced from raw milk exhibit a complex microbiota, characterized by a sequence of different microorganisms from milk coagulation and throughout maturation. Lactic acid bacteria (LAB) play an essential role in traditional cheese making, either as starter cultures that cause the rapid acidification of milk or as secondary microbiota that play an important role during cheese ripening. The enzymes produced by such dynamic LAB communities in raw milk are crucial, since they support proteolysis and lipolysis as chief drivers of flavor and texture of cheese. Recently, several LAB species have been characterized and used as probiotics that successfully promote human health. This review highlights the latest trends encompassing LAB acting in traditional raw milk cheeses (from cow, sheep, and goat milk), and their potential as probiotics and producers of bioactive compounds with health-promoting effects. Full article

(This article belongs to the Special Issue Microorganisms and Their Importance in the Food Industry: Safety, Quality and Health Properties)

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