scholarly journals Preliminary studies on the in situ prevention of food spoilage fungi using antifungal Lactic acid bacteria

Author(s):  
Srileka Chinnaiyan ◽  
◽  
Vijila Kenas ◽  

Food loss is a major threat in the world and one-third of the food produced for human consumption are wasted. Many fungal species cause loss of food/raw materials like grains, fruits and vegetables throughout the world. Chemical preservatives and fungicides when used in food have negative impacts on health and the environment. Biopreservatives such as lactic acid bacteria (LAB) are effective, safe, biodegradable and have additional health benefits. The focus of this research is to survey the occurrence of native lactic acid bacteria with antifungal activity in various food sources and to obtain a potential lactic acid bacterial isolate for strategic application to control fungal pathogen in food products. In the present study, the population of lactic acid bacteria were about 104 to 105 cells in all food samples. Sixty isolates of lactic acid bacteria were obtained from samples collected. Of these, 21 exhibited inhibition towards the growth of Fusarium oxysporum and 13 isolates towards A. flavus. Ten of the total isolates exhibited inhibition towards both the test fungi. Based on potential of antifungal activity in the dual plate technique, six isolates were selected and subjected to fungal growth inhibition analysis using microplate. Of these six isolates, the isolate LABT3 showed the highest inhibition percentage (%) against both the target fungi. The isolate was tested for its growth and maximum growth was noted at 48 h and pH at this period was 5.16.

Author(s):  
Mercy Aboh ◽  
Ngozi Amaeze ◽  
Ijeoma Ikeji ◽  
Peters Oladosu

Increasing consumer demand for natural products have renewed food industry attention in bio preservation. Lactic acid bacteria are of particular interest as effective alternative to chemical preservation because of their food grade status. This work explores the effect of antifungal compounds produced by isolates of Lactobacillus sp on some selected pathogenic fungi growth. Samples of diary and fermented products were purchased from commercial vendors within the Federal Capital Territory (FCT) and screened for the presence of Lactobacillus sp. The Lactobacillus sp isolated were screened for antifungal activity against Aspergillus fumigatus, Candida albicans and Trichophyton rubrum using a dual culture assay. Strains with antifungal activity were identified and the fungal inhibitory activity was further evaluated. The effect of abiotic factors on the antifungal activity was evaluated by overlay assay under different temperature and pH. Majority of the identified isolates belonged to the genus Lactobacillus. Lactobacillus sp. produced antifungal compounds under different temperatures (25ºC, 30ºC and 37ºC). The antifungal compounds produced by Lactobacillus strains showed greater inhibitory activity on Aspergillus fumigatus. At 30ºC the percentage zones of inhibition range were 44.4%- 60.4%. All isolates showed stronger antifungal activity when grown at pH 4.0 and 5.0. At a pH 2.0 there was a total inhibition of fungal growth however, there was no inhibition of fungal growth at the pH 7.0. Lactic acid bacteria can be employed as effective alternative to chemical preservatives in food. Temperature and pH of the culture medium could influence the production of antifungal compounds by lactic acid bacteria.


2021 ◽  
Vol 72 (1) ◽  
pp. e400
Author(s):  
F. Panebianco ◽  
A. Caridi

The anti-mold activity of 397 strains of lactic acid bacteria was evaluated using both the spot method in Petri plates and coculture in liquid medium. The study led to the selection of 34 strains isolated from table olives or olive brines, 15 strains from dairy products, and 10 strains from sourdoughs, all able to inhibit a strain of Penicillium crustosum and/or a strain of Aspergillus section Nidulantes, prevailing in two Calabrian olive brines. Seven representative strains were identified as Lactobacillus pentosus (four strains) and Lactobacillus sanfranciscensis (three strains) and are currently under testing for their antifungal activity during table olive fermentation. This research constitutes an initial contribution to the control of fungal growth and mycotoxin accumulation during table olive fermentation. The selected strains could be used as adjunct cultures in table olive fermentation, allowing for the biological control of table olive safety.


Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 285
Author(s):  
Fernando H. Ranjith ◽  
Belal J. Muhialdin ◽  
Noor L. Yusof ◽  
Nameer K. Mohammed ◽  
Muhammad H. Miskandar ◽  
...  

Background: the antagonism activity of lactic acid bacteria metabolites has the potential to prevent fungal growth on mango. Methods: the potential of developing natural disinfectant while using watermelon rinds (WR), pineapple (PP), orange peels (OP), palm kernel cake (PKC), and rice bran (RB), via lacto-fermentation was investigated. The obtained lactic acid bacteria (LAB) metabolites were then employed and the in vitro antifungal activity toward five spoilage fungi of mango was tested through liquid and solid systems. Besides, the effect of the produced disinfectant on the fungal growth inhibition and quality of mango was investigated. Results: the strains Lactobacillus plantarum ATCC8014 and Lactobacillus fermentum ATCC9338 growing in the substrates PKC and PP exhibited significantly higher in vitro antifungal activity against Colletotrichum gloeosporioides and Botryodiplodia theobromae as compared to other tested LAB strains and substrates. The in-situ results demonstrated that mango samples that were treated with the disinfectant produced from PKC fermented with L. plantarum and L. fermentum had the lowest disease incidence and disease severity index after 16 days shelf life, as well as the lowest conidial concentration. Furthermore, PKC that was fermented by L. fermentum highly maintained the quality of the mango. Conclusions: lactic acid fermentation of PKC by L. fermentum demonstrated a high potential for use as a natural disinfectant to control C. gloeosporioides and B. theobromae on mango.


Author(s):  
Rihua Xu ◽  
Ren Sa ◽  
Junwei Jia ◽  
Lanlan Li ◽  
Xiao Wang ◽  
...  

The demand for “preservative-free” food products is rising, and biopreservation seems to be a potential alternative to replace or reduce the use of chemical preservatives. This study’s objective was to assess the antifungal activity of lactic acid bacteria (LAB) (n = 98) and the efficacy and applicability of the chosen bioprotective cultures against fungal spoilers in dairy products. First, 14 strains of antifungal strains were preliminarily screened by in vitro tests against Pichia pastoris D3, Aspergillus niger D1, Geotrichum candidum N1, Kluyveromyces marxianus W1, and Penicillium chrysogenum B1 and validated by challenge tests in yogurts, indicating that the fungal-inhibiting activity of LAB was species specific and yogurts fermented with antifungal LAB cultures were more effective in extending the shelf life. Secondly, the chosen 14 LAB strains were identified by the 16SrDNA sequence analysis and carbohydrate fermentation test. The results were as follows: 9 strains were Lactobacillus plantarum , 3 were Lactobacillus paracasei , 1 was Enterococus faecium , and 1 was Lactobacillus rhamnosus. Among them, active L. plantarum N7 was the chosen and studied factor that affects the antifungal activity using the response surface methodology (RSM). Finally, in situ tests were conducted to validate the activity of L. plantarum N7 in actual dairy products (whey beverage). Physicochemical and microbial indices of whey beverage during storage period exhibited that antifungal L. plantarum N7 could slow the fungal growth and be candidates of interest for industrial applications.


Author(s):  
J Aquarista Ingratubun ◽  
Frans G Ijong ◽  
Hens Onibala

Food fermentation is one of various food processing techniques that has sufficient benefits of nutrition values, and also contains lactic acid bacteria which potentially inhibit pathogenic bacteria, thus prolong shelf life of  products. Bakasang is a traditional fermented food from North Sulawesi since many years ago. Reported research of bakasang previously had described that lactic acid bacteria was the dominant isolates and therefore current research  aimed to isolate and identify the lactic acid bacteria which associated during fermentation day 1 and day 15, respectively. Raw materials used were 5 kg intestine and liver of skipjack brought from local market Bersehati Manado. The intestine and liver of skipjack were washed and smashed and mixed with 10% salt  and 5% rice  from weight of the samples and then filled into bottle to be fermented for 15 days. Every 3 days (1,3,6,9,12,15), the samples were collected and analyzed for total lactic acid bacteria by using Total Plate Count Method on de Mann Rogosa Sharpe Agar after incubation at 37°C for 24 h. The colonies  grown were transferred to Tryptic Soy Broth and followed by streaking them on Tryptic Soy Agar and the free growing colony on agar medium were isolated into slant agar which were used for biochemical test such as Gram’s staining, motility test, catalase test, oksidase test, H2S test, IMVIC test (Indole, Methyl Red, Voges Proskauer, Citrate) and carbohydrate fermentation. The results showed that Lactobacillus sp., Bacillus sp., Eubacterium sp., and Bifidobacterium sp. All these four bacteria were distributed from day 1 to day 15 of the fermentation process© Fermentasi bahan pangan merupakan salah satu dari sekian banyak teknik pengolahan makanan yang mempunyai banyak manfaat dari kualitas gizi, mengandung bakteri asam laktat sehingga menghambat bakteri patogen sehingga daya simpan lebih panjang. Bakasang merupakan makanan fermentasi tradisional masyarakat Sulawesi Utara yang sudah ada sejak lama. Penelitian yang telah dilakukan terhadap bakasang menghasilkan informasi bahwa terdapat bakteri asam laktat pada bakasang sehingga menjadi tujuan untuk mengisolasi dan identifikasi bakteri asam laktat selama proses fermentasi 1-15 hari. Bahan baku bakasang ialah jeroan (usus dan hati) ikan cakalang Katsuwonis pelamis sebanyak 5 kg yang diambil dari pasar Bersehati Manado. Sampel jeroan dibersihkan kemudian dihancurkan, ditambahkan garam 10% dan nasi 5% kemudian difermentasi selama 15 hari dengan mengambil tiap-tiap sampel setiap 1, 3, 6, 9, 12, dan 15 untuk dihitung jumlah bakteri asam laktat dengan menggunakkan metode Total Plate Count pada media de Mann Rogosa Sharpe Agar dan koloni yang tumbuh di tumbuhkan  kembali pada media Tryptic Soy Broth  dan digores kembali pada media Tryptic Soy Agar, koloni yang tumbuh digores pada media slant agar yang selanjutnya diidentifikasi bakteri asam laktat berdasarkan uji biokimia yaitu uji pewarnaan Gram, uji motility, uji katalase, uji oksidase, uji H2S dan uji IMVIC (Indole, MethylRed, Voges Proskauer, Citrate). Hasil menunjukkan bahwa selama proses fermentasi berlangsung terdapat 4 genera bakteri asam laktat sesuai yaitu Lactobacillus sp., Bacillus sp., Eubacterium sp., dan Bifidobacterium sp., ke 4 genera ini tersebar pada fermentasi hari 1 sampai hari ke 15©


2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Prabin Koirala ◽  
Ndegwa Henry Maina ◽  
Hanna Nihtilä ◽  
Kati Katina ◽  
Rossana Coda

Abstract Background Lactic acid bacteria can synthesize dextran and oligosaccharides with different functionality, depending on the strain and fermentation conditions. As natural structure-forming agent, dextran has proven useful as food additive, improving the properties of several raw materials with poor technological quality, such as cereal by-products, fiber-and protein-rich matrices, enabling their use in food applications. In this study, we assessed dextran biosynthesis in situ during fermentation of brewers´ spent grain (BSG), the main by-product of beer brewing industry, with Leuconostoc pseudomesenteroides DSM20193 and Weissella confusa A16. The starters performance and the primary metabolites formed during 24 h of fermentation with and without 4% sucrose (w/w) were followed. Results The starters showed similar growth and acidification kinetics, but different sugar utilization, especially in presence of sucrose. Viscosity increase in fermented BSG containing sucrose occurred first after 10 h, and it kept increasing until 24 h concomitantly with dextran formation. Dextran content after 24 h was approximately 1% on the total weight of the BSG. Oligosaccharides with different degree of polymerization were formed together with dextran from 10 to 24 h. Three dextransucrase genes were identified in L. pseudomesenteroides DSM20193, one of which was significantly upregulated and remained active throughout the fermentation time. One dextransucrase gene was identified in W. confusa A16 also showing a typical induction profile, with highest upregulation at 10 h. Conclusions Selected lactic acid bacteria starters produced significant amount of dextran in brewers’ spent grain while forming oligosaccharides with different degree of polymerization. Putative dextransucrase genes identified in the starters showed a typical induction profile. Formation of dextran and oligosaccharides in BSG during lactic acid bacteria fermentation can be tailored to achieve specific technological properties of this raw material, contributing to its reintegration into the food chain.


2008 ◽  
Vol 71 (8) ◽  
pp. 1724-1733 ◽  
Author(s):  
SUSAN ROUSE ◽  
DOUWE VAN SINDEREN

Lactic acid bacteria (LAB) are naturally associated with many foods or their raw ingredients and are popularly used in food fermentation to enhance the sensory, aromatic, and textural properties of food. These microorganisms are well recognized for their biopreservative properties, which are achieved through the production of antimicrobial compounds such as lactic acid, diacetyl, bacteriocins, and other metabolites. The antifungal activity of certain LAB is less well characterized, but organic acids, as yet uncharacterized proteinaceous compounds, and cyclic dipeptides can inhibit the growth of some fungi. A variety of microbes are carried on raw materials used in beer brewing, rendering the process susceptible to contamination and often resulting in spoilage or inferior quality of the finished product. The application of antimicrobial-producing LAB at various points in the malting and brewing process could help to negate this problem, providing an added hurdle for spoilage organisms to overcome and leading to the production of a higher quality beer. This review outlines the bioprotective potential of LAB and its application with specific reference to the brewing industry.


1990 ◽  
Vol 53 (9) ◽  
pp. 793-794 ◽  
Author(s):  
HANNU J. KORKEALA ◽  
PIA M. MÄKELÄ ◽  
HANNU L. SUOMINEN

The minimum, optimum, and maximum growth temperatures of ropy slime-producing lactic acid bacteria able to spoil vacuum-packed cooked meat products were determined on MRS-agar with temperature-gradient incubator GradiplateR W10. The minimum growth temperatures of slime-producing lactobacilli and Leuconostoc mesenteroides strain D1 were below −1°C and 4°C, respectively. The low minimum growth temperature allows these bacteria to compete with other bacteria in meat processing plants and in meat products causing ropiness problems. The maximum growth temperatures varied between 36.6–39.8°C. The maximum growth temperature of lactobacilli seemed to be an unstable character. Single lactobacilli colonies were able to grow above the actual maximum growth temperature, which is determined as the edge of continuous growth of the bacteria. The significance of this phenomenon needs further study.


2018 ◽  
Vol 9 ◽  
Author(s):  
Marcia Leyva Salas ◽  
Anne Thierry ◽  
Mathilde Lemaître ◽  
Gilles Garric ◽  
Marielle Harel-Oger ◽  
...  

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