Inactivation of Salmonella Enteritidis and Salmonella Senftenberg in Liquid Whole Egg Using Generally Recognized as Safe Additives, Ionizing Radiation, and Heat

2007 ◽  
Vol 70 (6) ◽  
pp. 1402-1409 ◽  
Author(s):  
IGNACIO ALVAREZ ◽  
BRENDAN A. NIEMIRA ◽  
XUETONG FAN ◽  
CHRISTOPHER H. SOMMERS

The effect of combining irradiation and heat (i.e., irradiation followed by heat [IR-H]) on Salmonella Enteritidis and Salmonella Senftenberg inoculated into liquid whole egg (LWE) with added nisin, EDTA, sorbic acid, carvacrol, or combinations of these GRAS (generally recognized as safe) additives was investigated. Synergistic reductions of Salmonella populations were observed when LWE samples containing GRAS additives were treated by gamma radiation (0.3 and 1.0 kGy), heat (57 and 60°C), or IR-H. The presence of additives reduced the initial radiation Dγ-values (radiation doses required to eliminate 90% of the viable cells) by 1.2- to 1.5-fold, the thermal decimal reduction times (Dt-values) by up to 3.5- and 1.8-fold at 57 and 60°C, respectively, and the thermal Dt-values after irradiation treatments by up to 3.4- and 1.5-fold at 57 and 60°C, respectively, for both Salmonella serovars. Of all the additives investigated, nisin at a concentration of 100 IU/ml was the most effective at reducing the heat treatment times needed to obtain a 5-log reduction of Salmonella. Thus, while treatments of 21.6 min at 57°C or of 5 min at 60°C should be applied to achieve a 5-log reduction for Salmonella in LWE, only 5.5 min at 57°C or 2.3 min at 60°C after a 0.3-kGy radiation pretreatment was required when nisin at a concentration of 100 IU/ml was used. The synergistic reduction of Salmonella viability by IR-H treatments in the presence of GRAS additives could enable LWE producers to reduce the temperature or processing time of thermal treatments (current standards are 60°C for 3.5 min in the United States) or to increase the level of Salmonella inactivation.

2006 ◽  
Vol 69 (9) ◽  
pp. 2066-2074 ◽  
Author(s):  
IGNACIO ALVAREZ ◽  
BRENDAN A. NIEMIRA ◽  
XUETONG FAN ◽  
CHRISTOPHER H. SOMMERS

Salmonella is a frequent contaminant on eggs and is responsible for foodborne illnesses in humans. Ionizing radiation and thermal processing can be used to inactivate Salmonella in liquid whole egg, but when restricted to doses that do not affect egg quality, these technologies are only partially effective in reducing Salmonella populations. In this study, the effect of ionizing radiation in combination with thermal treatment on the survival of Salmonella serovars was investigated. Of the six Salmonella serovars tested, Salmonella Senftenberg was the most resistant to radiation (Dγ = 0.65 kGy) and heat (D55°C = 11.31 min, z = 4.9°C). Irradiation followed by thermal treatment at 55 or 57°C improved the pasteurization process. Radiation doses as low as 0.1 kGy prior to thermal treatments synergistically reduced the D55°C and D57°C of Salmonella Senftenberg 3.6- and 2.5-fold, respectively. The D55°C and D57°C of Salmonella Typhimurium were reduced 2- and 1.4-fold and those of Salmonella Enteritidis were reduced 2- and 1.6-fold, respectively. Irradiation prior to thermal treatment would enable the reduction of heat treatment times by 86 and 30% at 55 and 57°C, respectively, and would inactivate 9 log units of Salmonella serovars.


2000 ◽  
Vol 63 (4) ◽  
pp. 451-456 ◽  
Author(s):  
PILAR MAÑAS ◽  
RAFAEL PAGÁN ◽  
JAVIER RASO ◽  
FRANCISCO J. SALA ◽  
SANTIAGO CONDÓN

The resistance of Salmonella Enteritidis (ATCC 13076), Salmonella Typhimurium (ATCC 13311), and Salmonella Senftenberg 775W (ATCC 43845) to ultrasonic waves under pressure treatments, at sublethal (manosonication) and lethal temperatures (manothermosonication) in citrate–phosphate buffer and in liquid whole egg was investigated. The influence of treatment parameters on the inactivation rate of manosonication was also studied. Decimal reduction times (Dt) of Salmonella Enteritidis, Salmonella Typhimurium, and Salmonella Senftenberg 775W corresponding to a heat treatment at 60°C in pH 7 buffer and in liquid whole egg were 0.068, 0.12, and 1.0 min for buffer, and 0.12, 0.20, and 5.5 min for liquid whole egg. Those corresponding to a manosonication treatment (117 microns, 200 kPa, 40°C) in both media were 0.73, 0.78, and 0.84 min, and 0.76, 0.84, and 1.4 min, respectively. When the amplitude of ultrasonic waves was increased linearly, the inactivation rate of manosonication increased exponentially. The inactivation rate also increased when pressure was raised. However, the magnitude of this increase was progressively smaller at higher pressures. The magnitude of the influence of the amplitude of ultrasonic waves and static pressure on the inactivation rate of manosonication was the same in the three serotypes investigated. Whereas a heat treatment at 60°C only attained a ½-log cycle reduction in the number of Salmonella Senftenberg 775W survivors, a manothermosonication treatment (117 microns and 200 kPa) at this temperature attained a 3-log cycle reduction.


2003 ◽  
Vol 20 (5) ◽  
pp. 593-600 ◽  
Author(s):  
Pilar Mañas ◽  
Rafael Pagán ◽  
Ignacio Alvarez ◽  
Santiago Condón Usón

2020 ◽  
Vol 8 (5) ◽  
pp. 791
Author(s):  
Caitlin E. Karolenko ◽  
Arjun Bhusal ◽  
Jacob L. Nelson ◽  
Peter M. Muriana

In the US, dried beef products (beef jerky) are a popular snack product in which the manufacture often requires the use of a heat lethality step to provide adequate reduction of pathogens of concern (i.e., 5-log reduction of Salmonella as recommended by the United States Department of Agriculture Food Safety and Inspection Service (USDA-FSIS)). Biltong, a South African-style dried beef product, is manufactured with low heat and humidity. Our objectives were to examine processes for the manufacture of biltong that achieves a 5-log reduction of Salmonella without a heat lethality step and with, or without, the use of additional antimicrobials. Beef pieces (1.9 cm × 5.1 cm × 7.6 cm) were inoculated with a 5-serovar mixture of Salmonella (Salmonella Thompson 120, Salmonella Heidelberg F5038BG1, Salmonella Hadar MF60404, Salmonella Enteritidis H3527, and Salmonella Typhimurium H3380), dipped in antimicrobial solutions (lactic acid, acidified calcium sulfate, sodium acid sulfate) or water (no additional antimicrobial), and marinaded while vacuum tumbling and/or while held overnight at 5 °C. After marination, beef pieces were hung in an oven set at 22.2 °C (72 °F), 23.9 °C (75 °F), or 25 °C (77 °F) depending on the process, and maintained at 55% relative humidity. Beef samples were enumerated for Salmonella after inoculation, after dip treatment, after marination, and after 2, 4, 6, and 8 days of drying. Water activity was generally <0.85 by the end of 6–8 days of drying and weight loss was as high as 60%. Trials also examined salt concentration (1.7%, 2.2%, 2.7%) and marinade vinegar composition (2%, 3%, 4%) in the raw formulation. Nearly all approaches achieved 5-log10 reduction of Salmonella and was attributed to the manner of microbial enumeration eliminating the effects of microbial concentration on dried beef due to moisture loss. All trials were run as multiple replications and statistical analysis of treatments were determined by repeated measures analysis of variance (RM-ANOVA) to determine significant differences (p < 0.05). We believe this is the first published report of a biltong process achieving >5.0 log10 reduction of Salmonella which is a process validation requirement of USDA-FSIS for the sale of dried beef in the USA.


Author(s):  
Malek Amiali ◽  
Michael Ngadi ◽  
James P. Smith ◽  
Vijaya Raghavan

This study sought to evaluate the effect of PEF parameters such as electric field intensity and number of pulses on the inactivation of Escherichia coli O157:H7 and Salmonella Enteritidis suspended in liquid whole egg. The medium was inoculated with 108 CFU ml-1 of E. coli O157:H7 or S. Enteritidis and was treated continuously at 10, 20 or 30°C using electric field intensity of either 20 or 30 kV cm-1. A biphasic instant reversal PEF waveform with up to 105 pulses of 2 µs in width was applied. Bacterial inactivation increased with increasing applied electric field intensity, number of pulses and processing temperature. Maximum reductions of 3.9 and 3.6 log cycles were obtained for E. coli O157:H7 and S. Enteritidis, respectively. The maximum input energies required to inactivate E. coli O157:H7 and S. Enteritidis were 538 and 914 J, respectively. The higher kinetic value was obtained for S. Enteritidis (0.043 µs-1) representing the more heat–PEF sensitive bacteria compared to E. coli O157:H7.


1999 ◽  
Vol 62 (9) ◽  
pp. 999-1003 ◽  
Author(s):  
KELLEY P. KNIGHT ◽  
FRANCIS M. BARTLETT ◽  
ROBIN C. McKELLAR ◽  
LINDA J. HARRIS

D-values (decimal reduction times) and z-values (increase in temperature required for a 1-log change in D-value) for Listeria monocytogenes Scott A were determined in liquid whole egg with nisin (0 or 10 μg ml−1) and NaCl (0 or 10%) by a submerged glass ampoule procedure. Samples were plated onto nonselective agar at appropriate intervals, and D-values were determined using a modified biphasic logistic equation. Addition of NaCl increased D-values at all temperatures tested. The addition of nisin to unsalted liquid whole egg resulted in a rapid 4-log reduction in viable counts within the first hour. Nisin significantly (P ≤ 0.05) decreased D-values at lower (&lt;58°C) temperatures in both unsalted and salted liquid whole egg but had little effect on the D-values at current minimum U.S. and Canadian pasteurization temperatures (60°C without NaCl; 63°C with NaCl). However, when nisin was added 2 h prior to heat treatment, D-values were significantly (P ≤ 0.05) reduced at these temperatures. Inhibitory levels of nisin were detected in the liquid whole egg postpasteurization. Nisin could have a favorable impact on the control of L. monocytogenes in pasteurized liquid egg products.


1998 ◽  
Vol 61 (1) ◽  
pp. 107-109 ◽  
Author(s):  
RICHARD K. GAST ◽  
PETER S. HOLT

Culturing egg contents to detect Salmonella enteritidis (SE) has become an important tool for identifying infected laying flocks and thereby reducing the transmission of SE to humans by contaminated eggs. The present study evaluated the efficacy of supplementing incubating egg pools with selective and nonselective enrichment broth media (prepared at higher than usual concentrations) for rapidly isolating SE by a direct plating culture method. When 100-ml pools of liquid whole egg from a mixture of 60 egg contents were contaminated with approximately 10 SE cells each, supplementation with ferrous sulfate or with concentrates of either tryptone soya broth or Rappaport-Vassiliadis broth significantly improved SE recovery. When 100-ml egg-contents pools were contaminated with approximately 2 SE cells each, the addition of concentrated tryptone soya broth to incubating egg pools resulted in significantly better SE recovery than did iron supplementation. Efficient presumptive detection of very low incidences and levels of SE contamination by direct plating was thus accomplished in a total of 48 h by adding concentrated tryptone soya broth to incubating egg pools.


2003 ◽  
Vol 66 (6) ◽  
pp. 999-1006 ◽  
Author(s):  
JAMES D. SCHUMAN ◽  
BRIAN W. SHELDON

Although the transmission of L. monocytogenes to humans via pasteurized egg products has not been documented, L. monocytogenes and other Listeria species have been isolated from commercially broken raw liquid whole egg (LWE) in both the United States and Ireland. Recent Listeria thermal inactivation studies indicate that conventional minimal egg pasteurization processes would effect only a 2.1- to 2.7-order-of-magnitude inactivation of L. monocytogenes in LWE; thus, the margin of safety provided by conventional pasteurization processes is substantially smaller for L. monocytogenes than for Salmonella species (a 9-order-of-magnitude process). The objective of this study was to evaluate the inhibitory effects of nisin on the survival and growth of L. monocytogenes in refrigerated and pH-adjusted (pH 6.6 versus pH 7.5) ultrapasteurized LWE and in a liquid model system. The addition of nisin (1,000 IU/ml) to pH-adjusted ultrapasteurized LWE reduced L. monocytogenes populations by 1.6 to &gt;3.3 log CFU/ml and delayed (pH 7.5) or prevented (pH 6.6) the growth of the pathogen for 8 to 12 weeks at 4 and 10°C. Bioactive nisin was detected in LWE at both pH values for 12 weeks at 4°C. In subsequent experiments, Listeria reductions of &gt;3.0 log CFU/ml were achieved within 24 h in both LWE and broth plus nisin (500 IU/ml) at pH 6.6 but not at pH 7.5, and antilisterial activity was enhanced when nisin was added as a solution rather than in dry form.


1995 ◽  
Vol 58 (3) ◽  
pp. 273-279 ◽  
Author(s):  
D. DOBBENIE ◽  
M. UYTTENDAELE ◽  
J. DEBEVERE

The effect of glucose oxidase (GOX) in different GOX/glucose combinations on four commonly occurring microorganisms in liquid whole egg was evaluated. The addition of a combination of 500 U GOX and 0.5 g glucose in 100 ml liquid whole egg killed Salmonella enteritidis, Micrococcus luteus and Bacillus cereus inoculated at 103cells/ml after 5 days of storage at 7°C, and showed a bacteriostatic activity on Pseudomonas fluorescens. The latter possesses the strongest catalase activity of the four bacteria tested, enabling it to more rapidly break down the hydrogen peroxide produced enzymatically by the GOX/glucose system. The efficacy of the above-mentioned combination was tested on the natural contamination flora of liquid egg and compared to the effect of a simple β-d-glucono-δ-lactone (GDL) treatment (0.7 g/100 ml). The GOX/glucose combination prolonged the lag phase by 6 days. Subsequently, the bacterial flora started to develop, but growth remained retarded by 2 log units. Since GDL did not exert antibacterial activity, growth inhibition by the GOX/glucose system cannot be ascribed to a pH decrease as a result of the production of gluconic acid in the system.


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