50 research outputs found
Maintaining the safety and quality of beef carcass meat
No full textContamination of animal carcasses during slaughtering procedures is undesirable, but unavoidable in the conversion of live animals to meat for consumption. Internal muscle tissues are essentially sterile, and most initial contamination of red meat carcasses is contributed by the hide during removal (Elmonssalami and Wassef, 1971; Gill and Penny, 1979; Gill et al., 1976). The exposed surface of the hide and the hair accumulate dust, dirt and faecal material, and this is the primary source of bacterial contamination during slaughter (Ayres, 1955; Shotts et al., 1961). The factors that affect the extent of this contamination are reviewed by Patterson (1969) and Grau et al. (1968). Much of the microflora transferred to the tissue surfaces, while aesthetically undesirable, is nonpathogenic; however, pathogens such as Salmonella, Campylobacter and pathogenic Escherichia coli can be present.This is a chapter from Dickson, J.S. and G.R. Acuff. 2017. Maintaining the Safety and Quality of Beef Carcass Meat. IN Ensuring safety and quality in the production of beef. Volume 1: Safety. 2017. Acuff, G.R. and J.S. Dickson (editors). Burleigh Dodds Science Publishing. Sawston, Cambridge, UK. doi: 10.19103/AS.2016.0008.12. Posted with permission.</p
Processes to Preserve Spice and Herb Quality and Sensory Integrity During Pathogen Inactivation
No full textSelected processing methods, demonstrated to be effective at reducing Salmonella, were assessed to determine if spice and herb quality was affected. Black peppercorn, cumin seed, oregano, and onion powder were irradiated to a target dose of 8 kGy. Two additional processes were examined for whole black peppercorns and cumin seeds: ethylene oxide (EtO) fumigation and vacuum assisted-steam (82.22 °C, 7.5 psia). Treated and untreated spices/herbs were compared (visual, odor) using sensory similarity testing protocols (α = 0.20; β = 0.05; proportion of discriminators: 20%) to determine if processing altered sensory quality. Analytical assessment of quality (color, water activity, and volatile chemistry) was completed. Irradiation did not alter visual or odor sensory quality of black peppercorn, cumin seed, or oregano but created differences in onion powder, which was lighter (higher L*) and more red (higher a*) in color, and resulted in nearly complete loss of measured volatile compounds. EtO processing did not create detectable odor or appearance differences in black peppercorn; however visual and odor sensory quality differences, supported by changes in color (higher b*; lower L*) and increased concentrations of most volatiles, were detected for cumin seeds. Steam processing of black peppercorn resulted in perceptible odor differences, supported by increased concentration of monoterpene volatiles and loss of all sesquiterpenes; only visual differences were noted for cumin seed. An important step in process validation is the verification that no effect is detectable from a sensory perspective.This article is published as Duncan, Susan E., Kayla Moberg, Kemia N. Amin, Melissa Wright, Jordan J. Newkirk, Monica A. Ponder, Gary R. Acuff, and James S. Dickson. "Processes to Preserve Spice and Herb Quality and Sensory Integrity During Pathogen Inactivation." Journal of food science 82, no. 5 (2017): 1208-1215. doi: 10.1111/1750-3841.13702. Posted with permission.</p
The use of xylitol to minimize contamination of beef carcass surfaces with salmonella typhimurium and escherichia coli o157:h7
No full textEffects of a 10% xylitol solution (X) on adhesion of Escherichia coli O157:H7
and Salmonella serotype Typhimurium to meat surfaces were examined utilizing three
approaches. In Experiment 1, rifampicin-resistant strains of E. coli O157:H7 and S.
Typhimurium were dispersed in xylitol or a peptone solution (containing approximately
8.9 mean log per ml of each pathogen) and used to inoculate beef outside round meat
surfaces. Samples were then rinsed with water or not rinsed in a 2X2 factorial
arrangement. No interaction existed between inoculum type and post-inoculation
treatments (P > 0.84). Incubation of pathogens in peptone or xylitol had minimal impact
on pathogen adhesion (P > 0.76). Rinsing reduced counts by approximately 0.5 log
CFU/cm2 (P < 0.01). Experiment 2 meat samples received a pretreatment of a water
rinse, xylitol, or no rinse, followed by inoculation with pathogens dispersed in peptone
solution (containing approximately 8.6 log mean log per ml of each pathogen). Samples
received a post-inoculation treatment of a water rinse, xylitol rinse or no rinse in a 3X3
factorial arrangement. No interactions between pre- and post-inoculation factors were
observed for surface pathogen load (P > 0.50). Post-inoculation rinsing reduced counts by approximately 0.5 log CFU/cm2 (P < 0.01) with no difference between water and
xylitol (P > 0.64). Experiment 3 carcass surfaces were inoculated with pathogens at an
initial level of 5.5 log CFU/cm2 and received a hot (35����C) water wash, 2.5% L-lactic
acid spray, 10% xylitol spray, lactic acid + xylitol or hot water + xylitol. Pathogen
counts were taken at 0 and 24 h post treatment. Lactic acid treatments reduced
Salmonella by 3.3 log CFU/cm2 at 0 h (P < 0.01) and by 2.6 log CFU/cm2 after 24 h (P <
0.02). Hot water treatments reduced Salmonella by 1.5 log CFU/cm2 at 0 h (P < 0.07).
Xylitol did not minimize pathogens (P > 0.62) nor did it increase effectiveness of other
treatments. These data indicate that xylitol is ineffective at preventing E. coli O157:H7
and S. Typhimurium adhesion to meat surfaces
Use of flourescent surrogate organisms for enteric pathogens in validation of carcass decontamination treatments
No full textDuring the harvesting process, meat products can become contaminated with
enteric pathogens, such as Escherichia coli O157:H7 and Salmonella Typhimurium.
Surrogates for these pathogens would be beneficial for validating carcass
decontamination treatments. Surrogate organisms are organisms that behave similarly to
specific pathogens but are non-pathogenic and can be used to determine efficacy of
decontamination regimes for pathogens. The surrogates proposed are non-pathogenic,
ampicillin-resistant E. coli biotype I strains that were previously isolated from beef cattle
hides. Each E. coli strain was transformed to express a fluorescent protein (red: EcRFP;
green: EcGFP; yellow: EcYFP) that is detectable under an ultraviolet light source.
Surface areas on hot boned beef carcasses (clod, brisket, outside round) were inoculated
with a fecal slurry containing EcRFP, EcGFP, EcYFP and rifampicin-resistant E. coli
O157:H7 and S. Typhimurium. Surface regions were then treated in a model spray
cabinet using an initial water wash (28��C) followed by treatments using 2% L-lactic acid
(55��C), hot water (95��C at source) or a combination of the two. Treatments were
compared for their effectiveness at reducing populations of inoculated (4.7 to 6.7 log CFU/cm2) E. coli, S. Typhimurium, EcRFP, EcGFP and EcYFP. Log reductions for
inoculated organisms were calculated individually and then total and average surrogate
cocktail values were calculated.
All decontamination treatments reduced the inoculated numbers of pathogens and
surrogates to near or below the detection limit of 0.5 log CFU/cm2. The combined
treatment resulted in the greatest log reductions. The three individual surrogate
organisms varied in log reductions according to the different decontamination treatments
applied; however, log reductions for the total surrogate cocktail did not differ
significantly from that of E. coli O157:H7. With the exception of EcYFP, the individual
surrogates and average surrogate cocktail were significantly more resistant to microbial
interventions including lactic acid than S. Typhimurium. Because abattoirs utilize
different carcass decontamination treatments, it is difficult for one single fluorescent
protein-producing isolate to accurately represent the behavior of E. coli O157:H7 or S.
Typhimurium. Instead, surrogates should be used as a total cocktail to accurately
represent the effectiveness of different treatments for reduction of enteric pathogens
Standardization of Inoculation Procedures for Salmonellae and Surrogate Bacteria for Validating Spice/Herb Pathogen Reduction Processes
No full textSuitable spice inoculation procedures using surrogates of Salmonella are needed to perform adequate validations of spice disinfection processes. In this study, inoculation procedures of dried oregano and onion powder (OP) were developed and standardized using Salmonella, and Pediococcus faecium, as a potential surrogate. The effectiveness of traditional liquid inoculation was compared with dry inoculation of spices using silica and talcum powder (as inert vehicles for the microorganisms). A small amount of inoculated OP was used as starter for inoculation of larger bathes of OP. The stability of the inoculated microorganisms was monitored over time at -18, 4, and 25 ��C.
Salmonella strains isolated from outbreaks associated with spices (SRSS) and nonassociated with spices (non-SRSS) were evaluated to determine their appropriateness to represent the most resistant pathogenic strains during spice desiccation processes.
For dry oregano, the final concentrations of SRSS, non-SRSS, and P. faecium were 5.5, 3.6, and 4.2 log CFU/g, respectively, when using a liquid inoculation. When removing 18% of the oregano���s EO, the concentration of SRSS, non-SRSS, and P. faecium increased to 7.2, 5.1, and 6.4. log CFU/g, respectively; and when removing 58% of the oregano���s EO, the final counts were 7.0, 5.6, and 7.2 log CFU/g, respectively. Dry inoculation of oregano using pre-inoculated inert powders yielded in silica: 6.7, 5.0, and 6.9 CFU/g, and in talcum: 6.0, < 3, and 7.8 log CFU/g of SRSS, non-SRSS, and P. faecium, respectively.
For OP, liquid inoculation was not successful since the consistency changed from powdery to clumpy and sticky. However, the OP consistency was maintained when iii inoculating in a 1:50 v/w (inocula/OP) ratio. After desiccation, SRSS, non-SRSS, and P. faecium had a reduction of 0.7, 0.8, and 0.0 log CFU/g of SRSS, non-SRSS, and P. faecium.
The SRSS showed higher resistance to desiccation than the non-SRSS, whereas P. faecium showed the greatest resistance between the 3 groups of microorganisms.
In general, all microorganisms were more stable at -18 and 4 ��C than at 25 ��C during storage independently of the matrix teste
Improving the microbiological quality and safety of fresh-cut tomatoes by low dose electron beam irradiation
No full textThe effect of electron beam irradiation upon microbiological quality and safety of fresh-cut tomatoes was studied. Preliminary studies were conducted to ensure reliability of the rifampicin-resistant strain versus the parent strain of Salmonella serovar Montevideo for use in this study. Growth curve, heat tolerance and lactic acid resistance studies were performed, all of which showed no differences in behavior between the organisms. Fresh tomatoes were obtained from a local supplier and then cut into cubes with stem scars being separated. Both cubes and stem scars were inoculated with a rifampicin- resistant strain of either Salmonella Montevideo or Salmonella Agona, separated into treatment groups and treated by electron beam irradiation at 0.0 kGy (control), 0.7 kGy or 0.95 kGy. The effect of electron beam irradiation was determined for Salmonella, yeast, mold, and lactic acid bacteria (LAB) populations as well as pH on tomato cubes and stem scars over a 15-day storage period at 4??C. Results indicated that while irradiation treatment significantly reduced most microbial populations on tomato samples, there were no differences in the microbial populations between treatments of 0.7 kGy or 0.95 kGy. Irradiation at either dose resulted in a significant reduction of Salmonella Montevideo when compared to the control, with an initial reduction of 1.8 and 2.2 log10 CFU/g on tomatoes for 0.7 kGy and 0.95 kGy, respectively. LAB, yeasts and molds were more resistant to the treatment than Salmonella. Populations present on stem scars and tomato cubes did experience some differences in log reductions, possibly due to the protective effect of the stem scar on microorganisms. However, no differences were detected between the two Salmonella serotypes in response to irradiation treatment. This study indicates that doses of irradiation greater than 1 kGy should be used in fresh-cut tomatoes to eliminate significant populations of pathogens, as well as to ensure the microbial quality of the product. Additional studies also need to be conducted to examine the effects of higher irradiation doses on the sensory qualities of fresh-cut tomatoes
Improving chemical aqueous based intervention methods for microorganism elimination from fresh produce surfaces
No full textMany intervention methods theoretically have the potential to eliminate
microorganisms. However, they do not perform efficiently once applied to fruits and
vegetables. In this study Salmonella Typhimurium LT2 and hydrogen peroxide (H2O2)
were used as model systems on 6 different types of produce to determine the effect of
produce surface characteristics on sanitizer effectiveness.
Microbial attachment on produce surfaces was induced after 3 h of drying at 24����C
and high relative humidity (RH). Afterwards, produce was stored for 3 subsequent days
and washed with sterilized tap water for 5, 10 and 15 minutes to separate weakly from
strongly attached microorganisms from the produce surface. The strongly attached
microorganisms were then treated with 3% H2O2 for 1, 3, and 5 minutes. These results
were compared to the log reduction curves obtained with a pure liquid culture and 3%
H2O2. Additionally, contact angle of water and diiodomethane on each type of surface
were measured and used as indicator of wettability, and for calculating surface tension
characteristics of the produce surfaces. Then these surface characteristics were related to
the bacterial attachment and population reduction values obtained after applying the
treatments. In general, the geometric mean equation was the most useful in predicting the
surface tension values of produce surface and the polar and non-polar components of
produce surface tension.
Our results suggest that surface properties, such as roughness and surface tension
of fruits and vegetables are important factors limiting decontamination. These surface
properties allow the formation of micro-air pockets within the rough surface, thus
contributing to create a protective environment for microorganisms and reducing the
effectiveness of the chemical aqueous based intervention methods applied. Wettable
surfaces (water contact angle < 90����) allowed more bacteria to attach after the washing
and H2O2 chemical treatments. Roughness and surface polarity are intrinsic
characteristics of produce surfaces which affect wettability and the spreading and
penetration of the sanitizer treatment on the produce surface. Rough surface and porosity,
considered an extreme case of roughness, enhance a deeper cell internalization and a
protective environment for bacteria
Thermal Lethality Validation for Human Pathogenic Salmonella and the Salmonella Surrogate Enterococcus Faecium on Chicken Feathers and Blood
No full textWith the passage of the FDA Food Modernization Act (FSMA) in 2011 and its implementing rules, food safety preventive controls may be developed and used to prevent food safety hazards from being transmitted in finished products, including for covered members of the animal foods/feeds producing industry (21CFR��507). The following study was designed to provide both short- and long-term benefits to the poultry rendering industry by providing data to describe and validate the lethality of high heat processing to S. enterica on poultry carcass offal (blood and feathers), generate scientific data allowing the comparison of thermal lethality to Salmonella with the non-pathogen Enterococcus faecium NRRL B-2354 to determine differences in lethality by application of heat, and determine the utility of E. faecium NRRL B-2354 for inplant validation of high heat processing during the rendering of chicken by-products. Samples of Salmonella or surrogate-inoculated chicken blood and feathers were loaded into metallic vessels and submerged into distilled water tempered to 180, 190, or 200��F for 0, 0.5, 1, 2, 3, 4, or 5 min and 190, 200, or 210��F for 0, 3, 6, 9, 12, 15, or 18 min, respectively. In addition, a cumulative thermality for samples of Salmonella and E. faecium tempered to 200��F for 5 min and 300��F for 18 min, respectively, was completed. Statistical analysis determined there was only one significant difference in chicken blood-obtained D-values of the pathogen and surrogate, with the interaction of microorganism x temperature (P=0.0006) but effect interactions of microorganism x model (P=0.7340) and microorganism x temperature x model (P=0.3535) were not statistically different. Also, effect interactions for microorganism x temperature (P=0.4609), microorganism x model (P=0.5371), and microorganism x temperature x model (P=0.8527) were not statistically significant for determination of pathogen or surrogate D-valuesin chicken feathers. Data generated indicate significant lethality to Salmonella cocktail, 7.4��0.03 log10 CFU/ml in blood and 8.6��0.02 log10 CFU/g in feathers, respectively. E. faecium NRRL B-2354 was inactivated during thermal processing to 7.8��0.04 log10 CFU/ml in blood and 8.6��0.07 log10 CFU/g in feathers
Interventions for ensuring food safety in mangoes during phytosanitary treatments
No full textIncreased consumption combined with increasing risk to foodborne illnesses
makes it necessary to identify potential sources of contamination in the food chain and
apply intervention processes that prevent/minimize the risk of contamination. The
current study investigated the effect of the decontamination treatments with chlorine and
lactic acid on the survival of Salmonella on the rind and stem scar portions of inoculated
mangoes. The presence of the pathogen in the treatment water, internalization and the
effect of the treatments on the quality of the fruit were also determined.
For scar (hydrothermal), a 3.0 log reduction was obtained for control and
additional reductions of approximately 2.2 and 1.3 log cycles were obtained with lactic
acid and chlorine respectively. Data indicates reduction in pathogen population in
cooling for all the treatments except two (Control ��� increase of 0.3 logs, LA-LA ���
increase of 0.3 logs).
A 0.5 log reduction was obtained for the control (initial - 4.4 log10 CFU/10 cm2)
and additional reductions of approximately 1.7 and 1.3 log cycles were obtained for
treatments with lactic acid and chlorine respectively during hydrothermal treatment on the rind. For cooling, lactic acid and chlorine gave an overall reduction of approximately
1.3 and 1.4 logs respectively compared to control.
Although Salmonella was not detected in the core stem tissue by direct plating
method for most of the samples, it was detected after the enrichment method. The
pathogen was detected on the rind, stem scar and the stem tissue for most of the samples
for as long as 12 days. Salmonella was detected in treatment water with and without
sanitizers after dipping mangoes. Lactic acid was found to be more effective in reducing
pathogen population compared to chlorine in all the treatment combinations; however,
the sensory aspects (color and texture) of the fruit were compromised
Comparison of Antimicrobial Treatments Applied via Conventional Spray or Electrostatic Spray to Reduce Shiga-Toxigenic Escherichia coli (STEC) on Chilled Beef Outside Rounds
No full textThe purpose of this study was to compare the efficacy of different antimicrobial interventions: lactic acid, lauric arginate ester, cetylpyridinium chloride or peracetic acid applied with either conventional spray or hand-held electrostatic spray to reduce populations of Shiga-toxin producing Escherichia coli (STEC).
Hot-boned beef outside rounds were inoculated within 1 hour after harvest with a cocktail of 8 serotypes of Shiga-toxigenic E. coli (STEC8). Outside rounds were chilled upon transport back to Texas A&M University, and then hung on flame-sterilized meat hooks at 4��C for 36 hours to simulate a contaminated full carcass side in the chiller. Then, outside rounds were treated with lactic acid, lauric arginate ester, cetylpyridinium chloride, peracetic acid, or water (control) using conventional spray or electrostatic spray. Pre-treatment and post-treatment samples were excised from all rounds to evaluate the efficacy of all interventions and the mode with which they were applied.
Lactic acid applied with conventional spray achieved the greatest reduction of
STEC8 populations compared to all other treatments. In most cases, reductions obtained by conventional spray and electrostatic spray were not significantly different. The only treatment that differed significantly between conventional spray and electrostatic spray was lactic acid. Among the treatments applied with electrostatic spray, lauric arginate ester produced the greatest reduction of STEC8. If carcass interventions have similar performance between conventional and electrostatic spray, the use of the electrostaticspraying system would be advantageous by saving water and antimicrobial. Spray type and intervention must be paired appropriately for optimum beef safety
