Strategy to inactivate Clostridium perfringens spores in meat products
ABSTRACT The current study aimed to develop an inactivation strategy for Clostridium perfringens spores in meat through a combination of spore activation at low pressure (100-200 MPa, 7 min) and elevated temperature (80 °C, 10 min); spore germination at high temperatures (55, 60 or 65 °C); and inactivation of germinated spores with elevated temperatures (80 and 90 °C, 10 and 20 min) and high pressure (586 MPa, at 23 and 73 °C, 10 min). Low pressures (100-200 MPa) were insufficient to efficiently activate C. perfringens spores for germination. However, C. perfringens spores were efficiently activated with elevated temperature (80 °C, 10 min), and germinated at temperatures lethal for vegetative cells (≥55 °C) when incubated for 60 min with a mixture of l-asparagine and KCl (AK) in phosphate buffer (pH 7) and in poultry meat. Inactivation of spores (∼4 decimal reduction) in meat by elevated temperatures (80-90 °C for 20 min) required a long germination period (55 °C for 60 min). However, similar inactivation level was reached with shorter germination period (55 °C for 15 min) when spore contaminated-meat was treated with pressure-assisted thermal processing (568 MPa, 73 °C, 10 min). Therefore, the most efficient strategy to inactivate C. perfringens spores in poultry meat containing 50 mM AK consisted: (i) a primary heat treatment (80 °C, 10 min) to pasteurize and denature the meat proteins and to activate C. perfringens spores for germination; (ii) cooling of the product to 55 °C in about 20 min and further incubation at 55 °C for about 15 min for spore germination; and (iii) inactivation of germinated spores by pressure-assisted thermal processing (586 MPa at 73 °C for 10 min). Collectively, this study demonstrates the feasibility of an alternative and novel strategy to inactivate C. perfringens spores in meat products formulated with germinants specific for C. perfringens.
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- "D 100 °C -values around 20 min were determined in beef gravy for C. perfringens spores (Juneja et al., 2003), the same D-value of C. botulinum spores at 101 °C. These findings promoted research on the C. perfringens risk assessment on ready-to-eat and partially cooked meat and poultry products and its spore inactivation in different foods (Akhtar et al., 2009; Crouch et al., 2009; Gao et al., 2011; Golden et al., 2009; Varga and Szigeti, 2012). The ultrasound technology has a large number of applications in food processing such as defoaming, emulsification, extrusion, extraction , and waste treatment (Feng and Yang, 2011). "
ABSTRACT: Clostridium perfringens is a pathogen of concern in pasteurised foods. The main objective of this study was to use power ultrasound to enhance the thermal inactivation of C. perfringens spores in beef slurry. The effect of simultaneous ultrasound and heat (TS, thermosonication) on the spore inactivation in beef slurry was ﬁrst investigated. At 75 °C, a 60 min TS process (24 kHz, 0.33 W/g) resulted in a less than 1.5 log reduction for both C. perfringensNZRM 898 and NZRM 2621 spores. Then, the thermal inactivation ﬁrst order kinetic parameters of C. perfringens spores in beef slurry were estimated for the two strains. The D 105 °C - and z-values were 2.5 min and 10.6 °C for NZRM 898 and 1.8 min and 10.9 °C for NZRM 2621. After, the effect of a spore heat shock followed by ultrasound on its thermal inactivation in beef slurry was investigated. This heat shock + ultrasound pretreatment was able to double the spore thermal inactivation rate in beef slurry. For example at 95 °C D-value of 20.2 min decreased to 9.8 min, demonstrating that spore exposure to heat shock followed by ultrasonication enhanced its thermal inactivation.International Journal of Food Microbiology 04/2015; 206:17-23. DOI:10.1016/j.ijfoodmicro.2015.04.013 · 3.16 Impact Factor
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- "For example, spores of C. perfringens type A food poisoning isolates, unlike those of non-food borne isolates, are able to germinate in the presence of co-germinants Na þ and Pi or K þ ions. These minerals are intrinsically present in meat and processed meat products, and might significantly contribute to germination, outgrowth and proliferation in the meat during temperature abusive conditions . Similarly, C. difficile spores mainly germinate in the presence of taurocholate ubiquitously found in the intestinal tract of animals and humans; however, due to the aerobic nature of the small intestine, growth is arrested. "
ABSTRACT: Members of Clostridium genus are a diverse group of anaerobic spore-formers that includes several pathogenic species. Their anaerobic requirement enhances the importance of the dormant spore morphotype during infection, persistence and transmission. Bacterial spores are metabolically inactive and may survive for long times in the environment and germinate in presence of nutrients termed germinants. Recent progress with spores of several Clostridium species has identified the germinant receptors (GRs) involved in nutrient germinant recognition and initiation of spore germination. Signal transduction from GRs to the downstream effectors remains poorly understood but involves the release of dipicolinic acid. Two mechanistically different cortex hydrolytic machineries are present in Clostridium spores. Recent studies have also shed light into novel biological events that occur during spore formation (accumulation of transcriptional units) and transcription during early spore outgrowth. In summary, this review will cover all of the recent advances in Clostridium spore germination.Research in Microbiology 08/2014; 166(4). DOI:10.1016/j.resmic.2014.07.017 · 2.83 Impact Factor
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- "HPP is not without its limitations however. It is generally ineffective against bacterial spores (Akhtar et al. 2009; Shearer et al. 2000) and commercial HPP equipment is expensive. As a result, its application is generally limited to refrigerated foods and for use by high throughput commercial operations. "
ABSTRACT: High pressure processing (HPP) is an increasingly popular non-thermal food processing technology. Study of HPP's potential to inactivate foodborne viruses has defined general pressure levels required to inactivate hepatitis A virus, norovirus surrogates, and human norovirus itself within foods such as shellfish and produce. The sensitivity of a number of different picornaviruses to HPP is variable. Experiments suggest that HPP inactivates viruses via denaturation of capsid proteins which render the virus incapable of binding to its receptor on the surface of its host cell. Beyond the primary consideration of treatment pressure level, the effects of extending treatment times, temperature of initial pressure application, and matrix composition have been identified as critical parameters for designing HPP inactivation strategies. Research described here can serve as a preliminary guide to whether a current commercial process could be effective against HuNoV or HAV.Food and Environmental Virology 03/2013; 5(1):1-12. DOI:10.1007/s12560-012-9094-9 · 1.98 Impact Factor