Patricia A. Curtis

Cryogenic gas for rapid cooling of commercially processed shell eggs before packaging

Research was initiated to evaluate the effects on egg quality and microbial counts of rapidly cooling eggs by using cryogenic gases. Four trials were conducted utilizing a 2 × 2 factorial design with cryogenic cooling and Pseudomonas inoculation as the main variables. The 1440 eggs used in each trial were evaluated for cracked shells, Haugh units, and albumen pH. Cryogenically cooled treatment groups were successfully cooled from 37°C to 7°C in significantly less time than in a traditionally cooled pallet. The Haugh unit values obtained from traditionally cooled eggs were significantly (P > .001) lower than those from cryogenically cooled eggs. There was no significant difference in the albumen pH of the two groups. Internal and external bacterial counts revealed significantly fewer bacteria in the interior of cryogenically cooled eggs than in the interior of traditionally cooled eggs. However, after a 30-day storage period at 7°C, no difference was found in external and internal bacterial contamination rates. The results of this trial suggest that rapid cooling with cryogenic gases could be used in conjunction with current commercial egg processing to cool eggs prior to packaging. The successful commercial application of this procedure would reduce egg temperatures as well as the likelihood of Salmonella enteritidis growth in or on eggs. Thus, consumers would be provided with safer commercially processed shell eggs. In addition, the Haugh unit data indicate that rapid cooling with cryogenic gases enhances the quality of commercially processed shell eggs.

Internal and External Bacterial Counts from Shells of Eggs Washed in a Commercial-Type Processor at Various Wash-Water Temperatures†

The effects of two egg holding temperatures (15.5 and 26.7°C) and three wash-water temperatures (15.5, 32.2, and 48.9°C) on internal and external shell surface bacterial counts were tested by using a commercial-type egg-processing unit. Two experiments consisting of five trials, each of which included 360 eggs per treatment for a total of 2,160 per trial, were conducted during two seasons (summer and winter) for a total of 10 replicates per experiment. During the performance of each replicate, counts from tryptic soy agar (TSA) and MacConkey agar (MAC) were obtained from 10 egg samples which were collected prior to processing (prewash), immediately after washing (postwash), and after as-day cooling period at 7.2°C (postcool). No growth was observed on MAC plates in either experiment, indicating that fewer than 100 counts were detected. No significant differences (P > 0.05) were observed in the prewash, postwash, or postcool internal shell counts of eggs held at l5.5°C compared to internal counts of shells of eggs held at 26.7°C. Likewise, no significant differences (P > 0.05) were observed in the prewash, postwash, or postcool internal shell counts obtained from eggs washed in l5.5°C water compared with internal shell counts obtained from eggs washed in water at 32.2 or 48.9°C. On the basis of our data, spray washing eggs in l5.5°C water does not appear to increase internal shell bacterial counts. Because warm or hot wash water increases egg temperatures markedly, a reexamination of cold-water processing procedures may be in order.

The effects of commercial cool water washing of shell eggs on Haugh unit, vitelline membrane strength, aerobic microorganisms, and fungi

Current egg washing practices use wash water temperatures averaging 49 degrees C and have been found to increase internal egg temperature by 6.7 to 7.8 degrees C. These high temperatures create a more optimal environment for bacterial growth, including Salmonella Enteritidis if it is present. Salmonella Enteritidis is the most common human pathogen associated with shell eggs and egg products. Its growth is inhibited at temperatures of 7.2 degrees C and below. The objective of this study was to determine if commercially washing eggs in cool water would aid in quickly reducing internal egg temperature, preserving interior egg quality, and slowing microbial growth. During 3 consecutive days, eggs were washed using 4 dual-tank wash water temperature schemes (HH = 49 degrees C, 49 degrees C; HC = 49 degrees C, 24 degrees C; CC = 24 degrees C, 24 degrees C; CH = 24 degrees C, 49 degrees C) at 2 commercial processing facilities. A 10-wk storage study followed, in which vitelline membrane strength, Haugh unit, and aerobic microorganisms and fungi (yeasts and molds) were monitored weekly. As storage time progressed, average Haugh unit values declined 14.8%, the average force required to rupture the vitelline membrane decreased 20.6%, average numbers of bacteria present on shell surfaces decreased 11.3%, and bacteria present in egg contents increased 39.5% during storage. Wash water temperature did not significantly affect Haugh unit values, vitelline membrane strength, or the numbers of aerobic microorganisms and fungi within the shell matrices of processed eggs. Results of this study indicate that incorporating cool water into commercial shell egg processing, while maintaining a pH of 10 to 12, lowers postprocessing egg temperatures and allows for more rapid cooling, without causing a decline in egg quality or increasing the presence of aerobic microorganisms and fungi for approximately 5 wk postprocessing.

Reducing Colonization and Eggborne Transmission of Salmonella Enteritidis in Layer Chickens by In-Feed Supplementation of Caprylic Acid

Salmonella Enteritidis (SE) is a major foodborne pathogen responsible for causing gastrointestinal infections in humans, predominantly due to the consumption of contaminated eggs. In layer hens, SE colonizes the intestine and migrates to various organs, including the oviduct, thereby leading to egg yolk and shell contamination. This study investigated the efficacy of caprylic acid (CA), a medium-chain fatty acid, in reducing SE colonization and egg contamination in layers. Caprylic acid was supplemented in the feed at 0%, 0.7%, or 1% (vol/wt) from day 1 of the experiment. Birds were challenged with 10(10) log colony-forming units (CFU)/mL of SE by crop gavage on day 10, and re-inoculated (10(10) log CFU/mL) on day 35. After 7 days post first inoculation, eggs were collected daily and tested for SE on the shell and in the yolk separately. The birds were sacrificed on day 66 to determine SE colonization in the ceca, liver, and oviduct. The consumer acceptability of eggs was also determined by triangle test. The experiment was replicated twice. In-feed supplementation of CA (0.7% and 1%) to birds consistently decreased SE on eggshell and in the yolk (p<0.05). Supplementation of CA at 1.0% decreased SE population to ≈14% on the shell and ≈10% in yolk, when compared to control birds, which yielded ≈60% positive samples on shell and ≈43% in yolk. Additionally, SE populations in the cecum and liver were reduced in treated birds compared to control (p<0.05). No significant difference in egg production, body weight, or sensory properties of eggs was observed (p>0.05). The results suggest that CA could potentially be used as a feed additive to reduce eggborne transmission of SE.

Influence of Hen Age and Molting Treatments on Shell Egg Exterior, Interior, and Contents Microflora and Salmonella Prevalence During a Second Production Cycle

The objective of this study was to determine if increasing hen age and 3 different molting treatments influenced the total microflora counts or the prevalence of Salmonella spp. on the exterior of the egg shell, within the interior shell, or in the contents. Eggs from Hy-Line W-98 and Bovans White layer strains were sampled approximately every 28 d from 70 to 114 wk of age, with the molting period from 66 to 70 wk of age. Layers were utilized from the 35th North Carolina Layer Performance and Management Test and managed under identical husbandry practices. This study consisted of nonfasted, nonmolted, and feed-restricted treatments with the use of 135 eggs per layer strain, for a total of 270 eggs sampled per period. The exterior, interior shell, and contents were spiral plated onto plate count agar to calculate the total aerobic counts. Additional preenrichment, enrichment, conformational, and biochemical procedures were performed to test for the presence of Salmonella spp. Hen age and molting treatment significantly (P < 0.05) affected the microbial loads on all 3 egg components. Exterior, interior, yolk, and albumen counts increased during the molt period to as much as 1 log unit higher than the highest countable plate, which was 10(5). Exterior, interior, and contents counts significantly increased (P < 0.05) during period 15, with a significant increase (P < 0.05) in the interior also in period 14, and in the contents in periods 14 and 17. There were a total of 360 egg pools, and of those, 4 were positive Salmonella samples. Both the interior and exterior shell components and 2 of the 3 molting treatments had positive samples. Of these positives, 4 were confirmed as Salmonella Braenderup. Three positives were associated with the interior component, whereas 1 positive was associated with the exterior shell component. Three of the 4 samples were related to the nonfasted treatment, whereas the remaining positive was found in the non-molted treatment.

Simulation-based electrical safety training

Electrical safety has rapidly risen in prominence in industrial applications due to increased awareness of hazards and risks. There are numerous occupational health and safety organizations around the world that now mandate practices and procedures to maximize electrical safety in the workplace. Training workers to meet these requirements typically follows the standard methods based on seminars and short courses which have been widely used for many years. Maximizing electrical safety, however, cannot be achieved by simply memorizing facts or procedures taught in this environment. The critical aspect of electrical safety lies in the actions of the worker in the workplace-what people do in certain situations when given particular information is based on their higher-level thought process and their sequential decisions and actions. It is not possible to fully train workers in this skillset in advance, and the needs in this area are normally addressed on the job by direct observation and personal interaction. In this paper, a simulation-based electrical safety training module is described that allows the participant to move through a simulated environment while making observations and decisions and taking actions. The ability of the participant to recognize key facts and take appropriate actions when faced with simulated electrical safety scenarios can be scored and evaluated in the same manner as a typical computer game with the total score based on the accumulated choices of the participant. A score threshold can then be used to indicate the level to which the participant has mastered the training scenarios. Determining such a total score is exemplary of the necessary changes in assessment required when using virtual learning environments for training purposes.

Food Regulation in the United States

The two major food regulatory agencies are the Food and Drug Administration (FDA), which is part of the Department of Health and Human Services, and the U.S. Department of Agriculture’s (USDA) Food Safety and Inspection Service (FSIS). The FDA’s food regulatory responsibilities include all foods except meat, poultry, and egg products. FSIS’s regulatory responsibilities include meat, poultry, and egg products. There are other federal agencies such as the Environmental Protection Agency, the Occupational Safety and Health Administration, the Federal Trade Commission, and a few others that also periodically develop regulations associated with food, but food is not their primary focus. This chapter will review the different laws and responsibilities of the FDA and FSIS.

Assessing the impact of egg sweating on Salmonella Enteritidis penetration into shell eggs

&NA; Salmonella Enteritidis (SE) prevalence in eggs is a major concern to the egg industry. Some research has shown that egg sweating can increase Salmonella penetration into egg contents when refrigerated eggs are moved to a warmer temperature. This occurs when eggs are tempered before wash, to minimize thermal cracks. The effect of egg sweating on SE penetration into shell eggs over a 6 week storage period at 4°C was assessed. A 2 × 2 factorial of SE inoculation and egg sweating was utilized. Treatments included (SES) nalidixic acid (NA)‐resistant SE inoculated and sweated, (SENS) NA‐resistant SE inoculated and not sweated, (NSES) buffered peptone water (BPW) inoculated and sweated, and (NSENS) BPW inoculated and not sweated. Eggs were inoculated with 108 SE. Eggs formed condensation for approximately 17 min in a 32°C incubator. Shell rinse, shell emulsion, and egg contents were sampled then enumerated and assessed for prevalence of SE over a 6 wk storage period at 4°C. After wk 1, the SENS shell rinse had higher SE counts (0.32 log10 CFU/mL) than the other 3 treatments, where no SE was enumerated. A significant week by treatment interaction was found for the shell rinse SE detection (P < 0.05). In subsequent weeks, no SE counts were obtained from the egg shell rinse, shell emulsion, or egg contents. The SENS shell rinses had significantly higher SE prevalence than the SES rinses in weeks 1 (100% vs. 34.3%), 2 (57.6% vs. 22.2%), and 3 (38.2% vs. 11.1%) (P < 0.05). In samples from weeks 4, 5, and 6, there was no difference in SE prevalence between SES and SENS. Egg sweating did not increase SE penetration into the shell emulsion across treatment or week (P < 0.05). The decreasing trend of SE prevalence obtained over the study period indicate that refrigeration is effective at inhibiting SE growth. These results indicate that egg sweating occurring under common US egg handling practices is not harmful to egg safety.