Inactivation of<i>Bacillus subtilis</i>spores by combining ultrasonic waves under pressure and mild heat treatment

Raso, Javier; Palop, Alfredo; Pagán, Rafael; Condón, S.

doi:10.1046/j.1365-2672.1998.00593.x

Cited by 155 publications

(87 citation statements)

References 23 publications

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“…Recently, it was shown that a pressure of 100 MPa induces spore germination by activation of the germinant receptors and a pressure of 550 MPa opens channels for the release of DPA from the spore core (13). Our results confirm that the association of heat with pressure is very efficient for inactivation of B. anthracis spores, as has been shown for other Bacillus species spores (16). The high-pressure method represents a real improvement over other methods for the destruction of bacterial spores.…”

supporting

confidence: 76%

Combined Effects of High Hydrostatic Pressure and Temperature for Inactivation of Bacillus anthracis Spores

Cléry-Barraud

Gaubert²,

Masson

et al. 2004

Appl Environ Microbiol

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Spores of Bacillus anthracis are known to be extremely resistant to heat treatment, irradiation, desiccation, and disinfectants. To determine inactivation kinetics of spores by high pressure, B. anthracis spores of a Sterne strain-derived mutant deficient in the production of the toxin components (strain RP42) were exposed to pressures ranging from 280 to 500 MPa for 10 min to 6 h, combined with temperatures ranging from 20 to 75°C. The combination of heat and pressure resulted in complete destruction of B. anthracis spores, with a D value (exposure time for 90% inactivation of the spore population) of approximately 4 min after pressurization at 500 MPa and 75°C, compared to 160 min at 500 MPa and 20°C and 348 min at atmospheric pressure (0.1 MPa) and 75°C. The use of high pressure for spore inactivation represents a considerable improvement over other available methods of spore inactivation and could be of interest for antigenic spore preparation.Bacillus anthracis is a spore-forming gram-positive bacillus that causes anthrax. This zoonosis mostly affects herbivores. Occasionally humans contract the disease via the cutaneous route or via inhalation of aerosolized spores. The risk of biological warfare and bioterrorism is of increasing concern for governmental authorities, especially since the dissemination of spores through letters sent through the postal system. This caused 22 cases of human anthrax, with 5 fatal cases of inhalation anthrax (5). Consequently, research on anthrax prophylaxis and decontamination has been intensified. In this context, improved anthrax vaccine efficiency and spore inactivation methods are needed for safe antigenic preparation (2).Bacterial spores can survive in the environment for an extraordinarily long time; they are in a dormant state and resist physical and chemical stress. Several techniques, alone or combined, have already been tested for the inactivation of Bacillus spores: heat, acid pHs, nisin, ultrasonic waves, irradiation, and high pressure (4,11,17). High-pressure technology has been used since 1990 in the food industry for preservation and food processing. High hydrostatic pressure has proven to be efficient for destruction of vegetative bacteria, viruses, and yeasts, with bacterial spores being more resistant to pressure (6, 9). Due to a renewed interest in methods of B. anthracis spore inactivation, UV resistance was recently revisited (10), but high hydrostatic pressure had never been applied to the inactivation of B. anthracis spores. The aim of this study was to evaluate the efficacy of high-pressure treatment, alone and in association with heat, on the inactivation of spores of B. anthracis strain RP42, derived from the Sterne strain. B. anthracis Sterne is an attenuated nonencapsulated variant. This strain does not have the pXO2 plasmid, which carries the capsule genes of the vegetative bacterium. The RP42 strain contains the pXO1 plasmid from which the genes for edema factor and lethal factor production were deleted. This avirulent strain is a valuable model f...

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confidence: 76%

Combined Effects of High Hydrostatic Pressure and Temperature for Inactivation of Bacillus anthracis Spores

Cléry-Barraud

Gaubert²,

Masson

et al. 2004

Appl Environ Microbiol

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“…1). This would also indicate that the bacterial inactivation by MS is a phenomenon of the "all-or-nothing" type, probably due to the mechanical disruption of the cell envelopes, as has previously been observed by several researchers (20,21,23,26) in media with high a w s. Figure 2 shows the relationship between the temperature and decimal reduction time values to MS and MTS treatments of Salmonella serovar Enteritidis obtained in media with a w s of Ͼ0.99 ( Fig. 2A), 0.98 (Fig.…”

Section: Vol 69 2003 Salmonella Serovar Enteritidis Ms and Mts Inacmentioning

confidence: 73%

Inactivation of Salmonella enterica Serovar Enteritidis by Ultrasonic Waves under Pressure at Different Water Activities

Álvarez

Mañas

Sala

et al. 2003

Appl Environ Microbiol

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The inactivation of Salmonella enterica serovar Enteritidis by ultrasonic waves (20 kHz; 117-m wavelength) under pressure (175 kPa) at nonlethal temperatures (manosonication [MS]) and lethal temperatures (manothermosonication [MTS]) in media of different water activities has been investigated. Heat decimal reduction time values increased 30 times when the water activity was decreased from nearly 1 to 0.96, but the MS resistance was increased only twofold. The inactivation of Salmonella serovar Enteritidis by ultrasound under pressure at low water activities was a phenomenon of the "all-or-nothing" type. A synergistic lethal effect was observed between heat and ultrasound in media with reduced water activity; the lower the water activity, the greater the synergistic effect. This work could be useful for improving sanitation and preservation treatments of foods, especially those which are sensitive to temperature and those in which components protect microorganisms to heat. It also contributes to our knowledge of microbial inactivation mechanisms by MS and MTS treatments.During the last 3 decades, the number of food poisoning outbreaks in which different Salmonella enterica serotypes were involved has increased in industrialized countries (34,35). In the late 1980s, the frequency of isolation of Salmonella enterica serotype Enteritidis from eggs and egg products has increased steadily (25, 34). The influence of different environmental factors on the survival of other Salmonella serotypes has been investigated repeatedly (12,13,15,37), but little is known about their effect on Salmonella serovar Enteritidis.It is well-known that the heat resistance of microorganisms is influenced by many environmental factors. The water activity (a w ) of the heating medium is one of the most important factors (5,7,10,16,36). The thermal protective effect of media with reduced a w is very high (100-fold) (14,33). The use of high-intensity heat treatments to obtain the required microbial inactivation would impair food quality. Therefore, perhaps the new nonthermal methods of bacterial inactivation would be good alternative methods for the preservation and sanitation of products with reduced a w .Microbial inactivation by high-power ultrasound under pressure at nonlethal temperatures (manosonication [MS]) and lethal temperatures (manothermosonication [MTS]) was first reported by Sala et al. in 1995 (29). Recently, Raso et al. (27) reported the influence of temperature, pressure, and amplitude of ultrasonic waves on the lethal effect of ultrasound. (20), it could be deduced that the eventual advantages of MS or MTS for sanitation and/or food preservation purposes will be higher in temperature-sensitive foods (e.g., when raw materials are contaminated with very heat-resistant bacterial species or when food components protect microorganisms against heat).The purpose of this work was to investigate the inactivation of Salmonella serovar Enteritidis by ultrasonic waves under pressure at different temperatures in media of different wate...

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“…This technology works best when used in conjunction with heat and pressure [86,155], but it can be used alone for fruit juices, sauces, purees, and dairy products. Foods with particulates and other interfering substances do not react well to ultrasound.…”

Section: Ultrasoundmentioning

confidence: 99%

Food Safety Engineering: An Emergent Perspective

et al. 2009

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In general, food engineers are trained to solve engineering problems in the food industry. More specifically, the food engineer must specify the functional requirements, design, and testing of food products, and finally, the evaluation of products to check for overall efficiency, cost, reliability, and most importantly, safety. Food safety must be considered foremost as the overall engineering problem encountered in the food supply chain, and it must be solved from a food safety engineering perspective. This article will show that the food safety engineering perspective is needed in order to produce high quality food products (minimally processed) that are both safe and secure. This multi-disciplinary approach will involve certain engineering components: (i) predictive microbiology as a tool to evaluate and improve food safety in traditional and new processing technologies, (ii) advanced food contaminants detection methods, (iii) advanced processing technologies, (iv) advanced systems for re-contamination control, (v) advanced systems for active and intelligent packaging.

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Inactivation ofBacillus subtilisspores by combining ultrasonic waves under pressure and mild heat treatment

Cited by 155 publications

References 23 publications

Combined Effects of High Hydrostatic Pressure and Temperature for Inactivation of Bacillus anthracis Spores

Combined Effects of High Hydrostatic Pressure and Temperature for Inactivation of Bacillus anthracis Spores

Inactivation of Salmonella enterica Serovar Enteritidis by Ultrasonic Waves under Pressure at Different Water Activities

Food Safety Engineering: An Emergent Perspective

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