Control of spoilage fungi in yogurt using MicroGARD 200™, Lyofast-FPR2™ and HOLDBAC-YMC™ as bioprotectants

Abstract

The aim of this study was to assess the inhibitory effect of three commercial bioprotectant agents on the growth of yogurt-spoiling fungi. Mucor circinelloides, Mucor racemosus, Penicillium spp., Saccharomyces exiguus, and Candida intermedia, commonly involved in the spoilage of dairy products, were isolated from spoiled yogurt and were fully characterized using molecular and phenotypic methods. HOLDBAC-YMC™, Lyofast-FPR2™ and MicroGARD 200™ were used as antifungal products. An optimized experimental mixture design was applied to determine the proportion of each bioprotectant in terms of growth-inhibition response against the fungal strains in standard laboratory media. The results of the challenge tests showed that the application of bioprotectants inhibited the growth of the moulds in the range of 85–100% and the growth of yeast between 1.23 and 5.40 log cycles. The optimal combination of the bioprotectants was determined, tested in standard laboratory media and found to inhibit fungal growth. The antifungal effect of the optimal combination of the bioprotectants was validated in yogurt against the most resistant fungal species of the study, M. circinelloides and C. intermedia. The bioprotectants elicited antifungal effect in yogurt by completely inhibiting all of the tested fungi compared to controls. To the best of our knowledge, this is the first time a mixture of commercial bioprotectants has been tested on yogurt as a potential alternative for the biopreservation of yogurt in order to reduce spoilage of fermented dairy products and economic losses.

Evaluation of peroxyacetic acid, liquid buffered vinegar, and cultured dextrose fermentate as potential antimicrobial interventions for raw chicken livers

“…This patented antimicrobial is comprised of metabolites from milk, dextrose, or wheat with propionic bacteria or specific Lactococci (Von Staszewski & Jagus, 2008). Microbial inhibitory activities of the fermentate on dairy products, dressings, and some vegetables have been reported (Samapundo, de Baenst, Eeckhout, & Devlieghere, 2017; Serna‐Jiménez, Uribe‐Bohórquez, Rodríguez‐Bernal, Klotz‐Ceberio, & Quintanilla‐Carvajal, 2020; Von Staszewski & Jagus, 2008; Yang et al, 2021). BV and fermentates can be listed on the product labels as “vinegar” and “cultured milk” or “cultured dextrose,” respectively.…”

Selective Survival of Protective Cultures during High-Pressure Processing by Leveraging Freeze-Drying and Encapsulation

“…This production of organic acids is one example of the antagonistic activity leveraged when LAB are used as protective cultures for bio-preservation [7]. In addition to extended shelf-life, certain strains also confer health benefits to the consumer, demonstrating the virtuous duality of LAB as both probiotic and protective cultures [4]. Many of these desirable attributes are eliminated during treatment LAB's dynamic role as a fermentation starter culture extends shelf life, increases microbiological safety, and, in some cases, enhances the sensory and nutritional aspects of the fermented product [4][5][6].…”

“…In addition to extended shelf-life, certain strains also confer health benefits to the consumer, demonstrating the virtuous duality of LAB as both probiotic and protective cultures [4]. Many of these desirable attributes are eliminated during treatment LAB's dynamic role as a fermentation starter culture extends shelf life, increases microbiological safety, and, in some cases, enhances the sensory and nutritional aspects of the fermented product [4][5][6]. For example, during yogurt production, the fermentation of lactose decreases milk's pH to below 4.6, resulting in a product that is too acidic for pathogens and spoilage microorganisms to inhabit [4].…”

“…Many of these desirable attributes are eliminated during treatment LAB's dynamic role as a fermentation starter culture extends shelf life, increases microbiological safety, and, in some cases, enhances the sensory and nutritional aspects of the fermented product [4][5][6]. For example, during yogurt production, the fermentation of lactose decreases milk's pH to below 4.6, resulting in a product that is too acidic for pathogens and spoilage microorganisms to inhabit [4]. This production of organic acids is one example of the antagonistic activity leveraged when LAB are used as protective cultures for bio-preservation [7].…”