Simulated Commercial Conditions Research Articles

Inactivation efficacy of four commercial post-process treatments against Listeria monocytogenes and impact on the commercial quality of leafy greens

The problem of product contamination with human pathogenic microorganisms is still unsolved. Although prevention through the implementation of good agricultural practices and good manufacturing practices is the gold standard, product decontamination strategies can be used to complement preventive measures. Different bioprotective treatments have been suggested to reduce the risk of listeriosis in fresh produce, but more information is needed before industrial implementation. This study focused on the efficacy of four commercial treatments against Listeria monocytogenes growth and their effect on the organoleptic quality of baby spinach, cut romaine, cut iceberg, and shredded cabbage. The treatments included SafePro® (CHR Hansen, DK) and Holdbac® (DowDuPont, US), based on the use of lactic acid bacteria (LAB) cultures as well as two different bacteriophage solutions, ListShield (Intralytix, US) and PhageGuard Listex™ (PhageGuard, US). The selected treatments were tested under simulated commercial conditions. The application was performed after processing and before packaging using a fine mist spray. In all the trials, Listex™ showed the best results in reducing L. monocytogenes growth during shelf life in the four leafy greens chosen. Microbial reductions were close to 2 log units. L. monocytogenes reductions were observed 1 day after Listex™ application and the efficacy was maintained during storage (15 days at 7 °C). Organoleptic quality, including flavor, texture, browning/yellowing, decay, and visual appearance of the four leafy greens was not significantly affected by the application of Listex™ when compared to the untreated products. Post-process treatment with Listex™ based on bacteriophages effectively reduced L. monocytogenes and can be recommended as a control tool to reduce the risks for the presence of L. monocytogenes in leafy greens.

Vapor heat treatment for quarantine control of the oriental fruit fly (Diptera: Tephritidae) in papaya fruit from Thailand

A two-stage vapor heat treatment (VHT) is used commercially for disinfestation of the oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae) in various tropical fruits exported from Thailand to international markets. In the present study, VHT was tested against B. dorsalis in papayas to confirm a high level of quarantine security. The first instar larva of B. dorsalis was the most heat tolerant life stage. The VHT consists of heating papaya fruits with hot air at 50–80 % RH from ambient temperature to a fruit center temperature of 43 °C (dry pre-heating period), then heating with saturated hot air to 47 °C (wet heating period) with a 20-min hold at 47°. In large-scale confirmatory tests of this VHT treatment schedule, none of the treated 78,405 first instar larvae survived. Papayas at the color break maturity stage treated by VHT and held under simulated commercial export conditions showed no differences in fruit quality compared with non-treated controls. VHT showed high efficacy in disinfestation of papayas of B. dorsalis while maintaining fruit quality and could be used as a standard quarantine treatment for papaya exported from Thailand.

Effect of Chitosan-24-Epibrassinolide Composite Coating on the Quality Attributes of Late-Harvested Pomegranate Fruit under Simulated Commercial Storage Conditions.

This study evaluated the efficacy of chitosan (CH) functionalized with 24-epibrassinolide (EBR) coating in terms of preserving the postharvest quality of late-harvested pomegranate (cv. Wonderful) fruit. Late-harvested pomegranate fruit were immersed for 3 min in different surface treatment solutions—CH 1.5% (w/v), CH + 2 µM EBR, CH + 5 µM EBR, CH + 10 µM EBR and CH + 15 µM EBR—and distilled water was used as a control treatment. The fruit were air-dried and subjected to long storage duration at 5 °C with 85 ± 5 RH for 12 weeks. At 4-week sampling intervals, a batch of fruits was placed at 21 ± 2 °C and 65–70% RH for a further 3 d period to simulate retail conditions before measurements were taken. Fruit physiological responses, physico-chemical properties, phytochemical contents, antioxidant capacity and physiological disorders were monitored during storage. The results showed that the CH-EBR composite edible coatings significantly (p < 0.05) delayed degradative processes due to senescence. The CH-EBR treatments delayed colour, texture and total soluble solids (TSS) degradation and reduced weight loss, respiration, electrolyte leakage and spoilage compared to the control and CH treatment. The treatment effect was more noticeable on fruit treated with CH + 10 µM EBR, which exhibited lower weight loss (18.19%), respiration rate (7.72 mL CO2 kg−1 h−1), electrolyte leakage (27.54%) and decay (12.5%), and maintained higher texture (10.8 N) and TSS (17.67 °Brix) compared to the untreated fruit with respective values of 24.32%, 18.06 mL CO2 kg−1 h−1, 43.15%, 37.5%, 8.32 N and 17.03 °Brix. This was largely attributed to the significantly higher antioxidant content, including the ascorbic acid content, total phenol content, total anthocyanin content and DPPH (radical scavenging activity), of the coated fruit compared to the control fruit. Therefore, CH + 10 µM EBR treatment is recommended as a postharvest management strategy to improve the quality preservation of late-harvested pomegranate fruit during storage.

Peroxyacetic acid and chlorine dioxide unlike chlorine induce viable but non-culturable (VBNC) stage of Listeria monocytogenes and Escherichia coli O157:H7 in wash water

The elaboration of guidelines for the industry to establish minimum concentration to prevent cross-contamination during washing practices based on operational limits is the core of the recommended criteria for the use of sanitizers. Several studies have evidenced that sanitizers reduced the levels of foodborne pathogens. However, they might lead to the progress into a viable but non-culturable (VBNC) state of the cells. This evidence has raised concerns regarding the effectiveness of the recommended washing practices for the inactivation of microbial cells present in the process wash water (PWW). The present study evaluated if the most commonly used sanitizers, including sodium hypochlorite (chlorine), peroxyacetic acid (PAA) and chlorine dioxide (ClO2) at established operational limits induced the VBNC stage of Listeria monocytogenes and Escherichia coli O157:H7. Prevention of cross-contamination was examined in four different types of PWW from washing shredded lettuce and cabbage, diced onions, and baby spinach under simulated commercial conditions of high organic matter and 1 min contact time. The results obtained for chlorine showed that recommended operational limits (20–25 mg/L free chlorine) were effective in inactivating L. monocytogenes and E. coli O157:H7 in the different PWWs. However, the operational limits established for PAA (80 mg/L) and ClO2 (3 mg/L) reduced the levels of culturable pathogenic bacteria but induced the VBNC state of the remaining cells. Consequently, the operational limits for chlorine are satisfactory to inactivate foodborne pathogens present in PWW and prevent cross-contamination but higher concentrations or longer contact times should be needed for PAA and ClO2 to reduce the likelihood of the induction of VBNC bacteria cells, as it represents a hazard.

Assessment of mobility and pain in broiler chickens with identifiable gait defects

Gait defects, assessed as gait score (GS), is a common welfare problem in broiler chicken production. The aim of this study was to examine whether birds with GS2 experience pain and poor locomotor ability compared to birds of lower GS. From day 0–27 of age, 600 Ross 308 birds were housed in simulated commercial conditions (stocking density 40 kg/m2). On day 27, all birds were gait scored and 192 birds (4 blocks of 48 birds) were selected as experimental birds based on gait score (GS0 or GS2). On day 28, a runway test with and without obstacles was performed to examine the locomotor ability of the birds. Approximately 3 h before testing, the experimental birds were injected with the NSAID carprofen (25 mg/kg s.c.) or saline (equivalent volume). A Conditioned Place Preference (CPP) test was conducted on day 38, after 4 days of conditioning to a chamber (70 × 70 cm; painted either green with vertical stripes or orange with horizontal stripes) after injection with carprofen or saline. The broilers were expected to show a preference for the place in which they experienced a positive emotional state as induced by the mitigation of pain by carprofen. In the runway test, GS0 birds reached the end of the runway with obstacles faster compared to GS2 birds (P = 0.04) and tended to be faster than GS1 birds (P = 0.08). No effect of carprofen was found on the behaviour in the runway and no effect of GS on the behaviour in the runway without obstacles. In the CPP test, there was no effect of GS or carprofen on chamber preference (P > 0.05). The results showed clear differences between birds of GS2 and lower GSs in terms of locomotor response in the runway, indicating that locomotor ability was compromised with increased GS. The results could not confirm whether these differences in locomotor ability are related to or due to increased pain with increased GS.

Lactobacillus salivarius LI01 encapsulated in alginate-pectin microgels ameliorates D-galactosamine-induced acute liver injury in rats.

Acute liver failure is a clinical emergency associated with high mortality. Accumulating evidence indicates that gut microbiota participates in the progression of liver injury, and preventive therapies based on altering gut microbiota are of great interest. Previous studies demonstrated that Lactobacillus salivarius LI01 attenuates hepatic injury, though efficiency in curtailed in the harsh environment in the gastrointestinal tract. In this study, a system to encapsulate LI01 in alginate-pectin (AP) microgels was investigated. Encapsulation significantly enhances probiotic viability for long-term storage and heat treatment, and in simulated gastrointestinal fluids (SGF or SIF) and bile salt solutions. Acute liver injury was induced in Sprague-Dawley (SD) rats by D-galactosamine (D-GaIN) injection following pretreatment with probiotics. Liver and gut barrier function, cytokines, liver and gut histology, bacterial translocation, and gut microbiota were assessed. Administration of encapsulated LI01 more effectively upregulates hepatic anti-inflammatory cytokine IL-10 and TLR-3, restores expressions of gut barrier biomarkers Claudin-1 and MUC2 and attenuates destruction of mucosal ultrastructure compared with unencapsulated probiotics pretreatment. Pretreatment with AP-LI01 microgels altered the microbial community, decreasing the abundance of pathogenic taxa Ruminiclostridium, Dorea and Ruminococcaceae_UCG-004 and enriching beneficial taxa Ruminococcaceae_UCG-014, Eubacterium, and Prevotella_1 that produce short-chain fatty acids. These results suggest that AP encapsulation of LI01 boosts viability and attenuates liver injury by reducing inflammation and restoring intestinal barrier function. These beneficial effects are probably due to alternation of gut flora. These findings provide new insight into encapsulation technology and prevention of liver failure. KEY POINTS: • Alginate-pectin encapsulation enhances the viability of Lactobacillus salivarius LI01 under simulated commercial conditions and simulated gastrointestinal environment. • AP-LI01 microgel attenuates hepatic and intestinal inflammation and restores gut barrier function. • AP-LI01 microgel alters gut microbial community with increased SCFAs producers and decreased pathogenic microbes. • Beneficial improvements after administration of probiotics are highly associated with alternation of gut microbial community.

The effect of alternative feeding strategies during rearing on the behaviour of broiler breeder pullets

Broiler breeders are feed-restricted during rearing to avoid the negative consequences of obesity during lay due to their genetic potential for fast growth rate. Feed restriction leads to chronic hunger, frustration and lack of satiety as indicated by hyperactivity, restlessness and oral-redirected behaviours that can become abnormal repetitive behaviours (ARBs). The objective of this study was to examine the effect of a rationed alternative diet and non-daily feeding schedules on the behaviour of broiler breeder pullets under simulated commercial conditions. At 3 weeks of age, 1680 Ross 308 pullets were allocated into 24 pens where they were fed with one of four isocaloric treatments until 22 weeks: 1) daily control diet; 2) daily alternative diet; 3) 4/3 control diet (four on-feed days with three non-consecutive off-feed days per week); and 4) graduated control diet (the feeding frequency varied with age). The alternative diet included a fixed inclusion rate of 40 % soybean hulls and an increasing concentration of 1–5 % calcium propionate. Ten focal pullets per pen (five on on-feed days, five on off-feed days) were continuously observed for 10 min at 7, 10, 14, and 18 weeks of age, starting 30 min after feed delivery. Data were analyzed using mixed linear regression models, with pen nested in the model and age or time of day as a repeated measure. Throughout rearing, pullets on the daily control diet were more active than pullets on the other three treatments (P < 0.001), while pullets on the alternative diet spent more time inactive compared to pullets on the control diet, regardless of feeding schedule (P = 0.02). The percentage of time spent performing ARBs was also lower in pullets fed the alternative diet (1.7 ± 0.8 %) compared to control pullets (26.0 ± 0.8 %; P < 0.001) during early rearing. Pullets on non-daily schedules spent more time in ARBs and locomotion during off-feed days compared to on-feed days (P < 0.05). Our results indicate that a rationed alternative diet can alleviate behavioural signs of chronic hunger, whereas non-daily feed restriction can promote signs of satiety during on-feed days. Compared to daily feed restriction with a control diet, alternative feeding strategies can reduce some of the behavioural signs of feed restriction.

Validation of Edwardsiella ictaluri oral vaccination platform in experimental pond trials

AbstractSince its recognition in the early 1980s, enteric septicemia of catfish (ESC), caused by the gram‐negative enteric Edwardsiella ictaluri, is one of the most significant pathogens affecting catfish aquaculture. In efforts to improve disease management in U.S. catfish aquaculture, a live‐attenuated ESC vaccine and method of in‐pond oral vaccine delivery was developed. This work evaluated the efficacy of the oral delivery platform using a live‐attenuated E. ictaluri vaccine under simulated commercial conditions. Channel catfish fingerlings were orally vaccinated approximately 40–50 days poststocking by mixing the attenuated vaccine with feed using a patent‐pending mechanized delivery system. Across three discrete years under varying evaluation methods, vaccination resulted in significant improvements in survival, feed conversion ratio, feed fed, and total yield. An economic analysis of experimental data suggests a significant positive net economic benefit from vaccination. After accounting for a projected cost of vaccination, the realized improvements in survival and yield resulted in an estimated benefit exceeding $3,500/ha ($1,400/acre) on fingerling operations. These results suggest vaccinating channel catfish fingerlings against ESC is an effective strategy to mitigate ESC‐related losses and can significantly improve production efficiency and profitability on catfish operations.

The effect of alternative feeding strategies for broiler breeder pullets: 2. Welfare and performance during lay

ABSTRACTFeeding broiler breeders to satiety has negative consequences on their health and reproduction. Alternative feeding strategies during rearing can improve welfare, although their implications during lay are not well understood. The objective was to examine the effect of rearing feeding treatments on the reproductive performance and feeding behavior of broiler breeders under simulated commercial conditions. At 3 wk of age, 1,680 Ross 308 pullets were allocated to 24 pens under 1 of 4 isocaloric treatments: 1) daily control diet; 2) daily alternative diet (40% soybean hulls and 1 to 5% calcium propionate); 3) 4/3 control diet (4 on-feed days, 3 non-consecutive off-feed days per week); and 4) graduated control diet. Feeding frequency of the graduated treatment varied with age and finished on a daily basis. At 23 wk of age, group sizes were adjusted to 40 hens, and 5 mature Yield Plus Males roosters were introduced to each pen. Pens were under the same daily feeding management and same diet during lay. The performance of broiler breeders (growth rate, body weight uniformity, and reproductive performance) was determined until 64 wk of age. At the end of lay, feeding motivation was examined with a feed intake test and a compensatory feeding test. Data were analyzed using linear mixed regression models, with pen nested in the models and age as a repeated measure. The laying rate of hens reared on the graduated treatment decreased slower compared to control hens, resulting in a higher cumulative egg production (178.2 ± 3.8 eggs/hen) than control hens (165.2 ± 3.8 eggs/hen, P < 0.01) by 64 wk of age. Hens reared on non-daily feeding treatments laid lighter eggs with relatively heavier yolks and had higher feed intake at the end of lay than hens fed daily during rearing (P = 0.02). In conclusion, rearing feeding treatments impacted the growth rate and body weight uniformity during lay, feeding motivation at the end of lay, and the laying rate and hatchability depending on hens’ age.

Water sorption isotherms of cooked hams as affected by temperature and chemical composition

Abstract This study was focused on the determination of the chemical composition and experimentally obtaining the sorption isotherms for four samples of commercial cooked ham subjected to simulated commercial storage conditions. The isotherms were determined using the gravimetric method. The mathematical models of Guggenhein, Anderson and de Boer; Brunauer, Emmett and Teller; Halsey; Henderson; and Peleg were fitted to the experimental data. The Guggenhein, Anderson and de Boer model was chosen to best describe the isotherms as it had a very good fit. The increase in temperature reduced the equilibrium moisture content of the product. Increased relative humidity resulted in an increase in equilibrium moisture content of the product regardless of storage temperature. The differences in chemical composition between the samples affect the desorption isotherms. The higher the content and availability of the protein or the lower the fat content, the higher the equilibrium moisture content of the product.

Harvest Maturity and Storage Temperature Affect Postharvest Quality of ‘Wanda’ Datil Hot Pepper Grown under Protected Culture

Datil hot pepper (Capsicum chinense) has potential for increased production due to its unique, spicy flavor and aroma. However, few reports have been published related to postharvest handling characteristics. The purpose of this study was to determine the effect of harvest maturity on fruit quality under simulated commercial storage conditions. ‘Wanda’ datil pepper plants were grown hydroponically under protected culture. Fruit were harvested at yellow and orange maturity stages, placed in vented clamshell containers, and stored at 2, 7, or 10 °C for 21 days. Peppers harvested at yellow stage maintained greater quality than orange peppers during storage at all temperatures. Marketable fruit after 21 days for peppers harvested at the yellow stage was 94% (2 °C), 88% (7 °C), and 91% (10 °C); that for orange-stage peppers was 68%, 74%, and 82% for the same respective temperatures. No chilling injury (CI) symptoms were observed in these tests. Initial pepper moisture content was 90%, decreasing only slightly during 21 days of storage; weight loss ranged from 2% to 8%. Soluble solids content (SSC) was greater for peppers harvested at the orange stage (9.5%) than for those at yellow stage (7.8%). Neither harvest maturity nor storage temperature affected total titratable acidity (TTA; 0.13%) or pH (5.3). Respiration rate varied with temperature but not by harvest maturity and ranged from 12 to 25 mg·kg−1 per hour after 8 days of storage. Peppers harvested orange contained double the amount of total carotenoids as yellow fruit. Carotenoid content for yellow and orange peppers was 58 and 122 µg·g−1, respectively. Capsaicinoid content ranged from 1810 to 4440 µg·g−1 and was slightly greater for orange-harvested peppers. Datil peppers harvested at the yellow stage and stored in vented clamshell containers had better quality than peppers harvested at the orange stage after 21 days at 2 °C.

The effect of alternative feeding strategies for broiler breeder pullets: 1. Welfare and performance during rearing.

ABSTRACTBroiler breeders have impaired reproductive performance when fed to satiety but they can achieve an optimal hatching egg production under feed restriction. Feed restriction is a welfare concern due to signs of hunger, lack of satiety, and frustrated feeding motivation. The objective of this research was to examine the effect of a rationed alternative diet and non-daily feeding schedules on the performance and welfare of broiler breeder pullets reared under simulated commercial conditions. At 3 wk of age, 1,680 Ross 308 pullets were allocated to 24 pens fed with 1 of 4 treatments: 1) daily control diet (control); 2) daily alternative diet (40% soybean hulls and 1 to 5% calcium propionate); 3) 4/3 control diet (4 on-feed days per week; 3 non-consecutive off-feed days per week); and 4) graduated control diet (feeding frequency varied with age). Body weight and body weight uniformity were recorded at 3, 5, 7, 11, 17, and 21 wk of age. Pullets were scored for feather coverage, foot lesions, and hock burns biweekly. Physiological indicators (plasma glucose, corticosterone, hematology, and feather traits) and feeding motivation were also determined throughout rearing during on- and off-feed days. Data were analyzed using a linear mixed regression model, with pen nested in the model and age as a repeated measure. Compared to control, pullets under the 3 alternative feeding strategies had a lower feeding motivation during early rearing (P = 0.03), better feather coverage throughout rearing (P = 0.001), fewer feather fault bars (P = 0.006), and a delayed increase in the basophil to lymphocyte ratio (P = 0.001). These results indicate that the 3 alternative feeding strategies (the alternative, the graduated, and the 4/3 schedule) may decrease feeding motivation and alleviate stress compared to the control, suggesting an overall improvement in broiler breeder welfare without negative consequences on their performance.

Quantifying phosphine penetration through the bark of pine (Pinus radiata D.Don) logs

Phosphine (PH3) is used as an in-transit phytosanitary treatment (10-d fumigation period) for pine (Pinus radiata D.Don) logs exported from New Zealand to China. The ability of PH3 to penetrate through the bark of the logs is not well known. We designed equipment to accurately quantify PH3 penetration into the bark of wooden blocks (100 × 100 × 50 mm; n = 12) cut from the upper and lower trunk of recently harvested pine trees fumigated at 15 or 25 °C. Fumigations simulated commercial conditions consisting of two phases; phase I with 2.0 g m−3 of PH3 for the first 5 days (1–120 h) and 1.5 g m−3 of PH3 in phase II for the next 5 days (121–240 h). During the 10-d schedule, we achieved the required commercial CT (concentration × time) of ≥48,000 ppm h at both temperatures. Bark thickness (i.e., trunk location) did not significantly affect fumigant penetration. Phosphine penetration through the bark of the wooden blocks was greatest after each application, then the penetrated concentrations diminished over time. Greater penetration occurred at 15 °C than at 25 °C. Further studies are required to better understand the dynamics of PH3 penetration particularly at lower temperatures and through insect-infested blocks.

Corrigendum: The Effect of a Simulated Commercial Flight Environment With Hypoxia and Low Humidity on Clotting, Platelet, and Endothelial Function in Participants With Type 2 Diabetes - A Cross-Over Study.

[This corrects the article on p. 26 in vol. 9, PMID: 29487564.].

Efficacy of Lactic Acid, Lactic Acid–Acetic Acid Blends, and Peracetic Acid To Reduce Salmonella on Chicken Parts under Simulated Commercial Processing Conditions

The poultry processing industry has been undergoing a series of changes as it modifies processing practices to comply with new performance standards for chicken parts and comminuted poultry products. The regulatory approach encourages the use of intervention strategies to prevent and control foodborne pathogens in poultry products and thus improve food safety and protect human health. The present studies were conducted to evaluate the efficacy of antimicrobial interventions for reducing Salmonella on inoculated chicken parts under simulated commercial processing conditions. Chicken pieces were inoculated by immersion in a five-strain Salmonella cocktail at 6 log CFU/mL and then treated with organic acids and oxidizing agents on a commercial rinsing conveyor belt. The efficacy of spraying with six different treatments (sterile water, lactic acid, acetic acid, buffered lactic acid, acetic acid in combination with lactic acid, and peracetic acid) at two concentrations was evaluated on skin-on and skin-off chicken thighs at three application temperatures. Skinless chicken breasts were used to evaluate the antimicrobial efficacy of lactic acid and peracetic acid. The color stability of treated and untreated chicken parts was assessed after the acid interventions. The lactic acid and buffered lactic acid treatments produced the greatest reductions in Salmonella counts. Significant differences between the control and water treatments were identified for 5.11% lactic acid and 5.85% buffered lactic acid in both skin-on and skin-off chicken thighs. No significant effect of treatment temperature for skin-on chicken thighs was found. Lactic acid and peracetic acid were effective agents for eluting Salmonella cells attached to chicken breasts.

Validation of Organic Acid Interventions in Chicken Thighs to Reduce Salmonella under Simulated Commercial Processing Conditions

Validation of Organic Acid Interventions in Chicken Thighs to Reduce Salmonella under Simulated Commercial Processing Conditions

Trisodium phosphate and sodium hypochlorite are more effective as antimicrobials against Campylobacter and Salmonella on duck as compared to chicken meat

Little work has been reported on the use of commercial antimicrobials against foodborne pathogens on duck meat. We investigated the effectiveness of trisodium phosphate (TSP) and sodium hypochlorite (SH) as antimicrobial treatments against Campylobacter and Salmonella on duck meat under simulated commercial water chilling conditions. The results were compared to the same treatments on well-studied chicken meat. A six strain Campylobacter or Salmonella cocktail was inoculated (5ml) at two dilution levels (104 and 108cfu/ml) onto 25g duck or chicken meat with skin and allowed to attach for 10min. The meat was exposed to three concentrations of pH adjusted TSP (8, 10 and 12% (w/v), pH11.5) or SH (40, 50 and 60ppm, pH5.5) in 30ml water under simulated spin chiller conditions (4°C, agitation) for 10min. In a parallel experiment the meat was placed in the antimicrobial treatments before inoculation and bacterial cocktails were added to the meat after the antimicrobial solution was removed while all other parameters were maintained. Untreated controls and controls using water were included in all experiments. Bacterial numbers were determined on Campylobacter blood-free selective agar and Mueller Hinton agar or xylose deoxycholate agar and tryptone soya agar using the thin agar layer method for Campylobacter and Salmonella, respectively. All TSP concentrations significantly (p<0.05) reduced numbers of Campylobacter (~1.2–6.4logcfu/cm2) and Salmonella (~0.4–6.6logcfu/cm2) on both duck and chicken meat. On duck meat, numbers of Campylobacter were less than the limit of detection at higher concentrations of TSP and numbers of Salmonella were less than the limit of detection at all concentrations of TSP except one. On chicken meat, numbers of Campylobacter and Salmonella were less than the limit of detection only at the lower inoculum level and higher TSP concentrations. By contrast only some of the concentrations of SH significantly (p<0.05) reduced numbers of Campylobacter and Salmonella (~0.2–1.5logcfu/cm2) on both duck and chicken meats. None of the SH treatments resulted in numbers of either pathogen being less than limit of detection. Results indicate that chicken meat has the ability to effectively protect Campylobacter and Salmonella against the impact of trisodium phosphate and sodium hypochlorite while duck meat does not. This study suggests that trisodium phosphate has a strong potential for application in a commercial poultry processing to reduce Campylobacter and Salmonella specifically on duck meat.

Ripening Quality of ‘Bartlett’ Pears (Pyrus communis L.) Subjected to Phytosanitary X-ray Irradiation Treatment Followed by Simulated Retail Display

The objective of this study was to determine the effect of phytosanitary X-ray irradiation on the physicochemical properties and sensory attributes of early- and late-harvest ‘Bartlett’ pears (Pyrus communis L.) during ripening under simulated commercial conditions. Irradiation delayed ripening, which in turn affected respiration rate, ethylene production, and firmness. Irradiation decreased ethylene production in early- and late-harvest pears and maintained firmness as compared with the control pears. In the early-harvest pears, irradiation did not affect respiration rate, weight loss, or total soluble solids. However, in the late-harvest pears, irradiation resulted in an increase in respiration rate and weight loss and a decrease in total soluble solids. The appearance for irradiated early-harvest pears was rated lower by consumers, but there were no significant differences in the rest of the attributes. Consumers rated the irradiated late-harvest pears lower (P &lt; 0.05) than the non-treated pears for overall liking, texture, and flavor on a 9-point hedonic scale. Consumers perceived the late-harvest irradiated pears to be less sweet than the control (P &lt; 0.05), which correlated with total soluble solids of 12.4% for treated pears vs. 13.2% for the control. Our results show that there were significant differences between the early- and late-harvest pears in their responses to irradiation. Although some sensory attributes were negatively affected, the delay in ripening helped reduce bruising and mold development in irradiated pears during the retail display simulation.

Effect of different tumbling marination treatments on the quality characteristics of prepared pork chops.

The effect of different tumbling marination treatments (control group, CG; conventional static marination, SM; vacuum continuous tumbling marination, CT; vacuum intermittent tumbling marination, IT) on the quality characteristics of prepared pork chops was investigated under simulated commercial conditions. The CT treatment increased (p<0.05) the pH value, b* value, product yield, tenderness, overall flavor, sensory juiciness and overall acceptability in comparison to other treatments for prepared boneless pork chops. The CT treatment decreased (p<0.05) cooking loss, shear force value, hardness, gumminess and chewiness compared with other treatments. In addition, CT treatment effectively improved springiness and sensory color more than other treatments. However, IT treatment achieved the numerically highest (p<0.05) L* and a* values. These results suggested that CT treatment obtained the best quality characteristics of prepared pork chops and should be adopted as the optimal commercial processing method for this prepared boneless pork chops.

Impact of aeration and alkalinity on the water quality and product quality of transported tilapia—A simulation study

The effects of aeration and alkalinity on water quality and product quality of Nile tilapia (Oreochrmis niloticus) were determined for simulated commercial hauling conditions. Three types of aeration were tested: pure oxygen aeration with a fine bubble diffuser (Oxygen), air aeration with medium bubble diffusers (Air), and a combination of both pure oxygen aeration with a fine bubble diffuser and air aeration with a medium bubble diffuser (Mixed). Simulated transport hauls were conducted at two initial alkalinities: 1.74±0.11meq/L (Low) and 8.84±0.55meq/L (High).The Air treatments resulted in the lowest carbon dioxide concentration, and the highest pH and un-ionized ammonia concentrations. At high alkalinities, the Air treatments were unable to maintain adequate dissolved oxygen levels. The Mixed treatment resulted in reduced carbon dioxide and dissolved oxygen concentrations. The Oxygen treatment resulted the highest dissolved oxygen, highest carbon dioxide, and lowest pH and un-ionized ammonia. Un-ionized ammonia concentrations were higher with the High Alkalinity treatments because of higher pH. Significant mortality was observed in the Air treatments in both the Low- and High-Alkalinity treatments. Mortality in the Oxygen and Mixed treatments for both low and high alkalinities were comparable to that observed in commercial tilapia transport using fine bubble diffusers and pure oxygen.These results indicate that mortality due directly to hauling water quality will not be increased at high alkalinity, if pure oxygen aeration is used. The potential effects of water quality during hauling on survival and product quality may be less than the impact from (a) physical damage from loading and un-loading and (b) physiological problems resulting from pH and temperature shock during the transfer from the hauling tanks to retail holding systems, especially for fish of reduced fitness.