Influence of Acid Adaptation on the Probability of Germination of Clostridium sporogenes Spores Against pH, NaCl and Time

Abstract

The Clostridium sp. is a large group of spore-forming, facultative or strictly anaerobic, Gram-positive bacteria that can produce food poisoning. The table olive industry is demanding alternative formulations to respond to market demand for the reduction of acidity and salt contents in final products. while maintaining the appearance of freshness of fruits. In this work, logistic regression models for non-adapted and acid-adapted Clostridium sp. strains were developed in laboratory medium to study the influence of pH, NaCl (%) and time on the probability of germination of their spores. A Clostridium sporogenes cocktail was not able to germinate at pH < 5.0, although the adaptation of the strains produced an increase in the probability of germination at 5.0–5.5 pH levels and 6% NaCl concentration. At acidic pH values (5.0), the adapted strains germinated after 10 days of incubation, while those which were non-adapted required 15 days. At pH 5.75 and with 4% NaCl, germination of the adapted strains took place before 7 days, while several replicates of the non-adapted strains did not germinate after 42 days of storage. The model was validated in natural green olive brines with good results (>81.7% correct prediction cases). The information will be useful for the industry and administration to assess the safety risk in the formulation of new processing conditions in table olives and other fermented vegetables.

Exploring bacteria diversity in commercialized table olive biofilms by metataxonomic and compositional data analysis

“…were not detected in any table packaging analysed in this work above 0.01% of frequency. Some authors 36 , recently reported that a cocktail of diverse strains of C. sporogenes needed a pH value above 5.0 to germinate in both laboratory medium and table olive brine, which could explain why Clostridium was neither detected albeit pH value in certain samples was above 4.3. Our data are very similar to other studies on commercial table olives performed in markets of Spain 5 and Portugal 6 , although with more than 12 years of difference.…”

Effect of Pasteurized Low Acidic Indigenous Beverages Produced in Northern Cameroon on Germination of Bacillus and Geobacillus Spores Species

“…However, they may also be potentially hazardous because of the raw materials, the lack of hygiene during processing and use of rudimentary manufacturing processes, which are many potential routes of microbial contamination [8]. Due to their ubiquitous character, bacterial spores are distributed in the environment, soil, water, and plants, so they can easily contaminate food during processing [9]. Many studies reported the presence of spore-forming bacteria in indigenous beverages made in Cameroon [10,11].…”

“…8.2.7 International Journal for Research in Applied Sciences and Biotechnology www.ijrasb.com germination have been undertaken, given the importance of spores as agents of food spoilage and disease and given the necessity of germination for spores to exert eventually their deleterious effects. These inhibitors include low acid pH (less than 4.5) [9], aliphatic alcohols [16], nisin and fatty acids [17], plant essential oils [18] and many others compounds [19]. Indeed, according to authors [15], germination of spores of Bacillus species such as B. cereus, B. megapterium and B. subtilis is inhibited to more than 95% by ethanol at 2.4%, butanol at 0.1%, hexanol at 0.014%, and octanol at 0.006%.…”

Characterization and Processing of Table Olives: A Special Issue

“…The table olive industry is demanding alternative formulations to respond to market demand for the reduction of acidity and salt contents in final products, while maintaining the appearance of freshness of fruits. In the work by Valero et al [ 11 ], the authors develop logistic regression models for non-adapted and acid-adapted Clostridium sporogenes strains to study the influence of pH, NaCl, and incubation time on the probability of germination of their spores. They select the factor ranges so that the model could be applied to table olive processing.…”

“…To conclude, the present special issue consists of 10 original research papers and two review articles. The research papers, focused on recent research advances related to characterization and processing of table olives, have covered microbiological and chemical changes in table olives during spontaneous or controlled fermentation employing different cultivars [ 3 ], characterization of their composition of volatiles and the sensory profile [ 5 , 6 , 7 ], mineral composition [ 8 ] and bioavailability [ 9 ], changes in bioactive components (chlorophylls) by processing [ 10 ], optimized use of starter cultures for the improvement of the different fermentative processes [ 4 , 5 ], and new strategies to reduce sodium and additives, to stabilize the organoleptic properties and avoid defects [ 11 , 12 ].…”