Enhanced elimination of Salmonella Typhimurium and Campylobacter jejuni on chicken skin by sequential exposure to ultrasound and peroxyacetic acid

The present study investigated the effects of combined ultrasound (37 kHz, 380 W for 5 min) and peroxyacetic acid (PAA; 50–200 ppm) treatment on the reduction of Salmonella Typhimurium and Campylobacter jejuni on chicken skin. Ultrasound was not sufficient to inactivate S. Typhimurium (0.48 log CFU/g reduction) or C. jejuni (0.25 log CFU/g reduction), whereas PAA significantly (p < .05) reduced S. Typhimurium (0.93–1.59 log CFU/g reduction) and C. jejuni (0.77–1.52 log CFU/g reduction). However, maximum reductions of 2.21 and 2.08 log CFU/g were observed for S. Typhimurium and C. jejuni, respectively, for combined treatment with 5 min of ultrasound and 200 ppm PAA. Our results indicate that a combination of ultrasound treatment for 5 min and 200 ppm PAA was more effective in reducing S. Typhimurium and C. jejuni compared to the individual treatments, without significantly affecting the color or texture of the chicken skin, thus, demonstrating its potential to increase the microbial safety during poultry processing.     

The Effectiveness of Sanitizer Treatments in Inactivation of Salmonella spp. from Bell Pepper, Cucumber, and Strawberry

ABSTRACT: Four different postharvest treatments for removal of Salmonella from bell pepper and cucumber were examined, including washes with chlorinated water (HOCl; 200 ppm), acidified sodium chlorite (ASC; 1200 ppm), and peroxyacetic acid (PAA; 75 ppm), and treatment with gaseous chlorine dioxide (ClO₂; total 100 mg). Only ClO₂ gas was evaluated for decontamination of strawberries. Each produce was inoculated with approximately 1.0 × 10⁷ colony-forming units (CFU) of a 5-serovar cocktail of Salmonella on artificially created wounds, smooth surfaces, and stem scar tissue. For tests involving smooth surface inoculation, ASC and PAA treatments decreased contamination to undetectable levels on bell pepper and cucumber, while the chlorine treatment of bell pepper reduced contamination by approximately 2-logs. For stem scar contamination on bell pepper, ASC and PAA treatments both showed >2-log unit reductions, and chlorine treatment showed a <1-log unit reduction. For puncture wounds on bell pepper, HOCl, ASC, and PAA treatments reduced bacterial levels approximately 2-, 3-, and 1-log units, respectively, indicating that HOCl and ASC were more effective than PAA. These aqueous treatments of cucumber with puncture wounds reduced bacterial levels approximately 1-, 2-, and 2-log units, respectively. ClO₂ treatment decreased counts to undetectable levels on all inoculation sites on cucumber and on strawberry smooth surfaces, but failed to completely eliminate Salmonella from bell pepper and from the stem scar and the puncture wounds of strawberry. ASC treatment of bell pepper and ClO₂ gas treatments of cucumber showed the best efficiency for inactivation of Salmonella. ClO₂ treatments effectively reduced Salmonella cells inoculated on the smooth surface and stem scar of strawberries compared with unsanitized control.     

Survival of Penicillium expansum and Patulin Production on Stored Apples after Wash Treatments

ABSTRACT: Penicillium expansum is a widespread fungus found on apples that causes fruit decay and may lead to production of a toxic secondary metabolite, patulin. This study was undertaken to evaluate the effectiveness of several chemical sanitizers against P. expansum NRRL 2304 and to establish sanitizing wash treatments that would inhibit P. expansum growth and subsequent patulin production on Empire apples destined for cider. Wash treatments included 200 ppm NaOCl, 1% StorOx®, 0.5% potassium sorbate, 300 ppm SO₂, and 0% to 5% acetic acid. Spores of P. expansum or inoculated apple slices were dipped in sanitizing wash solution for 5 min, and mold growth and patulin production was monitored on subsequent storage. It was found that 0.5% potassium sorbate and 300 ppm SO₂ did not affect mold survival or patulin production; 1% StorOx® was effective against mold spores in solution (4 log Most Probable Number destruction of spores), but there was no significant reduction in spore count when the same solution was used to sanitize mold‐inoculated apple discs. Washing with 200 ppm NaOCl delayed growth of P. expansum on inoculated apple discs but failed to completely inhibit patulin production. Acetic acid solution (2% to 5%) was the most efficient chemical against P. expansum. A wash treatment with ≥2% acetic acid for more than 1 min is recommended to completely inhibit growth of P. expansum and subsequent patulin production on apples destined for cider.     

ACIDIFIED SODIUM CHLORITE, TRISODIUM PHOSPHATE AND POPULATIONS OF SALMONELLA TYPHIMURIUM AND STAPHYLOCOCCUS AUREUS ON CHICKEN-BREAST SKIN

The present study was designed to determine the individual and combined effects of acidified sodium chlorite (ASC) and trisodium phosphate (TSP) antimicrobial treatments. Chicken‐skin samples inoculated with Salmonella typhimurium and Staphylococcus aureus were separately dipped into sterile tap water, 10% TSP, 0.1% ASC, 0.1% ASC followed by 10% TSP and 10% TSP followed by 0.1% ASC for 15 s at 25C ± 1. On day 0, reductions were 1.4–1.6 log for S. Typhimurium and 1.1–2.1 log for S. aureus, while they were 1.8–2.9 and 0.7–1.7 log, respectively, on day 5 of storage. Results indicated that treatment with ASC solution alone was more effective than treatment with ASC and TSP solutions combined in reducing S. aureus populations on chicken skin during the entire storage period. Similarly, treatment with TSP solution alone was more effective than treatment with ASC and TSP solutions combined in reducing S. typhimurium populations on chicken skin on days 1, 3 and 5 of storage.     

Utilizing Acidic Sprays for Eliminating Salmonella enterica on Raw Almonds

ABSTRACT In‐shell or shelled almonds inoculated with Salmonella were sprayed with water, acetic acid, citric acid, acidified sodium chlorite, peroxyacetic acid, or a mixture of citric, hydrochloric, and phosphoric acids before testing for Salmonella on xylose‐lysine‐deoxycholate (XLD) agar and tryptic soy agar (TSA). Spraying acids on in‐shell almonds reduced about 0.48 to 1.88 and 0.22 to 0.67 log colony‐forming units (CFU)/g of Salmonella on XLD agar and TSA counts, respectively, on the in‐shell almonds but had no effect on the edible portion of the almonds (shelled almonds). When spraying acids on shelled almonds, a single spray application (1.6 mL acid solution/25 g of shelled almonds) with 1 min holding caused 0.72 to 1.93 and 0.38 to 1.35 log CFU/ g reductions of Salmonella counts on XLD agar and TSA, respectively. Increasing the holding time to 5 min did not enhance the reductions. When spraying shelled almonds, increasing the number of application (1 to 3 times) enhanced Salmonella reduction. Except for the peroxyacetic acids, increasing total holding time (5 to 120 min) improved the efficacies. Furthermore, increasing acid concentrations improved the efficacies of acetic, citric, and peroxyacetic acid treatments. Estimated 5‐log reductions on both TSA and XLD counts can be achieved under laboratory conditions using 10% citric acid by (1) the combination of shelling, 1 spraying, and 3 d of storage, (2) the combination of shelling, 2 sprayings, and 1 d of storage, or (3) the combination of shelling and 3 sprayings. Acidic sprays may be utilized for enhancing the microbiological safety of raw nuts.     

Comparison of Acidified Sodium Chlorite,Chlorine Dioxide,Peroxyacetic Acid and Tri-Sodium Phosphate Spray Washes for Decontamination of Chicken Carcasses

The objective of this study was to directly compare the antimicrobial effect of acidified sodium chlorite (ASC), chlorine dioxide (CD), peroxyacetic acid (PAA) and tri-sodium phosphate (TSP) on naturally occurring Campylobacter, Enterobacteriaceae and Pseudomonas spp. on the breast and neck skin of chicken carcasses treated post-evisceration and prior to primary chilling. Naturally contaminated Campylobacter-positive chicken carcasses, obtained from a commercial processing line immediately post-evisceration but prior to the inside–outside wash, were treated in a purpose-built automated spray rig. Replicated batch treatments for 15 and 30 s of chemical and water-only spray wash were performed. Untreated control carcasses were examined to provide baseline data for the initial numbers. Numbers of colony-forming units (CFU) per gram of skin excised from neck and breast locations were determined using selective agar media. For analysis, the results were subdivided into six microbe type/skin location combinations with each subdivision ranked by the following: (a) CFU remaining after treatment, (b) mean reductions and (c) the proportional change in numbers of samples below the limit of detection (LoD). The three groups of bacteria responded similarly to the chemicals applied. Campylobacter spp. were no more susceptible than the other two groups. No single chemical treatment gave the best effect across all ranking methods. Generally, ASC and TSP were more effective in reducing microbial counts than PAA, with CD and water having the least effect. A 30-s chemical treatment was usually more effective than a 15-s treatment. Where only a short (15 s) spray time is possible, ASC appears to be the most effective of the chemicals tested. Where longer treatments are possible, TSP becomes the most effective choice.     

The effect of calcinated calcium and chlorine treatments on Escherichia coli O157:H7 87-23 population reduction in radish sprouts

Abstract: The effect of calcinated calcium spray on Escherichia coli O157:H7 87–23 population reduction during radish sprout production was studied. Artificially inoculated radish seeds were soaked in sodium hypochlorite (NaOCl) solutions (200 and 20000 ppm), rinsed in distilled water, and sprayed with water or a calcinated calcium solution during sprouting. Microbial plate count was obtained at each step of the process and germination rate was determined after 72 h of sprouting. Scanning electron microscopy (SEM) was done on treated seeds and sprouts to locate which parts were populated by the E. coli cells. The results showed that the active compound in the calcinated calcium was calcium oxide. The treatment of 200 ppm NaOCl soaking followed by 0.04% calcinated calcium spray resulted in no microbial growth after a 72‐h sprouting, while maintaining a high germination rate. The 0.4% calcinated calcium spray significantly reduced the germination rate and is therefore not recommended. Soaking the seeds in a 20000 ppm chlorine solution achieved the highest E. coli count reduction (1.65 log CFU/g). However, the E. coli cells that survived the 20000 ppm chlorine soak grew to 6 log CFU/g sprouts after a 72‐h sprouting, significantly higher than the initial count on the seeds. The SEM microimages showed that the bacteria were mostly located in the roots of the radish sprouts and all across the seed surface. The E. coli O157:H7 87–23 cells appeared to be located in biofilms or embedded into the radish sprout tissues during sprouting. Practical Application: The seed sanitation treatment with 20000 ppm chlorine solution that is currently used by the sprout industry was once again found to be ineffective in eliminating inoculated pathogenic cells. More importantly, the remaining cells that have survived the chlorine wash would grow during sprouting to reach an alarmingly high cell concentration. The new observation of E. coli cells and sprout tissue interaction manifested as embedding of the cells in sprout tissues, if confirmed, will have a significant impact on the microbial safety intervention strategies used in the sprout industry. This research demonstrated the importance of eliminating all pathogens on the seeds before germination and sprouting.     

Inactivation of Bacillus cereus Spores on Red Chili Peppers Using a Combined Treatment of Aqueous Chlorine Dioxide and Hot‐Air Drying

The effect of a combined treatment using aqueous chlorine dioxide (ClO₂) and hot‐air drying to inactivate Bacillus cereus spores on red chili peppers was evaluated. Ten washed and dried pepper samples, each comprising half of a single pepper (Capsicum annuum L.), were inoculated with B. cereus spore suspension. The inoculated samples were washed with sodium hypochlorite (NaOCl; 50, 100, or 200 μg/mL) or ClO₂ (50, 100, or 200 μg/mL) solution for 1 min and then air‐dried (25 ± 1 °C, 47 ± 1% relative humidity), which was followed by drying with hot air at 55 °C for up to 48 h. The spore populations on the samples were enumerated and their a_w and chromaticity values were measured. The spore numbers immediately after treatment with NaOCl and ClO₂ were not significantly different. A more rapid reduction in spore numbers was observed in the samples treated with ClO₂ than those treated with NaOCl during drying. A combined treatment of ClO₂ and hot‐air drying significantly reduced the spore populations to below the detection limit (1.7 log CFU/sample). B. cereus spores on chili peppers were successfully inactivated by washing with ClO₂ solution followed by hot‐air drying whereas the pepper color was maintained.     

Switchgrass extractives to mitigate Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium contamination of romaine lettuce at pre- and postharvest

The antimicrobial potential of switchgrass extractives (SE) was evaluated on cut lettuce leaves and romaine lettuce in planta, using rifampicin-resistant Escherichia coli O157:H7 and Salmonella Typhimurium strain LT2 as model pathogens. Cut lettuce leaves were swabbed with E. coli O157:H7 or S. Typhimurium followed by surface treatment with 0.8% SE, 0.6% sodium hypochlorite, or water for 1 to 45 min. For in planta studies, SE was swabbed on demarcated leaf surfaces either prior to or after inoculation of greenhouse-grown lettuce with E. coli O157:H7 or S. Typhimurium; the leaf samples were collected after 0, 24, and 48 h of treatment. Bacteria from inoculated leaves were enumerated on tryptic soy agar plates (and also on MacConkey's and XLT4 agar plates), and the recovered counts were statistically analyzed. Cut lettuce leaves showed E. coli O157:H7 reduction between 3.25 and 6.17 log CFU/leaf, whereas S. Typhimurium reductions were between 2.94 log CFU/leaf and 5.47 log CFU/leaf depending on the SE treatment durations, from initial levels of ∼7 log CFU/leaf. SE treatment of lettuce in planta, before bacterial inoculation, reduced E. coli O157:H7 and S. Typhimurium populations by 1.88 and 2.49 log CFU after 24 h and 3 h, respectively. However, SE treatment after bacterial inoculation of lettuce plants decreased E. coli O157:H7 populations by 3.04 log CFU (after 0 h) with negligible reduction of S. Typhimurium populations. Our findings demonstrate the potential of SE as a plant-based method for decontaminating E. coli O157:H7 on lettuce during pre- and postharvest stages in hurdle approaches.     

Effectiveness of Individual or Combined Sanitizer Treatments for Inactivating Salmonella spp. on Smooth Surface, Stem Scar, and Wounds of Tomatoes

ABSTRACT: Unwaxed, green tomatoes ('Florida 47' cultivar) were contaminated with Salmonella and then treated with aqueous solutions of sodium hypochlorite (HOCl; 200 ppm), acidified sodium chlorite (ASC; 1200 ppm), peroxyacetic acid (PAA; 87 ppm), or chlorine dioxide gas (ClO₂; total 100 mg). Additionally, a combined treatment of immersion in HOCl, followed by immersion in ASC and then exposure to ClO₂ gas was investigated. Tomatoes were spot inoculated with a 5-strain Salmonella cocktail on smooth surfaces, stem scar tissue, or puncture wounds. A 3 replicate set of each of the sample groups was stored at 20 °C and 95% relative humidity (RH) and retested after 5 d. Greater than 4.0-log unit reductions of Salmonella spp. inoculated on the smooth surface of the tomatoes were seen for all aqueous sanitizer treatments, with Salmonella populations below the detection limit after 5 d of storage. All aqueous treatment groups showed > 1.0-log unit reductions in Salmonella at the stem scar and >2.0-log unit reduction at puncture wounds. The ClO₂ gas treatment reduced Salmonella to undetectable levels at the stem scar, but had no apparent effect on populations inoculated in puncture wounds. The combined treatment resulted in a 3.0-log unit reduction of inoculated Salmonella at puncture wounds. In all cases except for treatment with chlorine, surviving Salmonella populations did not increase after the 5 d of storage. Results of this study suggest the combined treatment was most effective for minimizing the risk of Salmonella contaminated on tomatoes.     

Effectiveness of trisodium phosphate, acidified sodium chlorite, citric acid, and peroxyacids against pathogenic bacteria on poultry during refrigerated storage

The effects of dipping treatments (15 min) in potable water or in solutions (wt/vol) of 12% trisodium phosphate (TSP), 1,200 ppm acidified sodium chlorite (ASC), 2% citric acid (CA), and 220 ppm peroxyacids (PA) on inoculated pathogenic bacteria (Listeria monocytogenes, Staphylococcus aureus, Bacillus cereus, Salmonella Enteritidis, Escherichia coli, and Yersinia enterocolitica) and skin pH were investigated throughout storage of chicken legs (days 0, 1, 3, and 5) at 3 +/- 1 degrees C. All chemical solutions reduced microbial populations (P < 0.001) as compared with the control (untreated) samples. Similar bacterial loads (P > 0.05) were observed on water-dipped and control legs. Type of treatment, microbial group, and sampling day influenced microbial counts (P < 0.001). Average reductions with regard to control samples were 0.28 to 2.41 log CFU/g with TSP, 0.33 to 3.15 log CFU/g with ASC, 0.82 to 1.97 log CFU/g with CA, and 0.07 to 0.96 log CFU/g with PA. Average reductions were lower (P < 0.001) for gram-positive (0.96 log CFU/g) than for gram-negative (1.33 log CFU/g) bacteria. CA and ASC were the most effective antimicrobial compounds against gram-positive and gram-negative bacteria, respectively. TSP was the second most effective compound for both bacterial groups. Average microbial reductions per gram of skin were 0.87 log CFU/g with TSP, 0.86 log CFU/g with ASC, 1.39 log CFU/g with CA, and 0.74 log CFU/g with PA for gram-positive bacteria, and 1.28 log CFU/g with TSP, 2.03 log CFU/g with ASC, 1.23 log CFU/g with CA, and 0.78 log CFU/g with PA for gram-negative bacteria. With only a few exceptions, microbial reductions in TSP- and ASC-treated samples decreased and those in samples treated with CA increased throughout storage. Samples treated with TSP and samples dipped in CA and ASC had the highest and lowest pH values, respectively, after treatment. The pH of the treated legs tended to return to normal (6.3 to 6.6) during storage. However, at the end of storage, the pH of legs treated with TSP remained higher and that of legs treated with CA remained lower than normal.     

Characterisation of oil oxidation,fatty acid,carotenoid, squalene and tocopherol components of hazelnut oils obtained from three varieties undergoing oxidation

Hazelnut oils obtained from three varieties of Chinese hybrid hazelnuts (cv. ‘Liaozhen 3 (LZ)’, ‘Pingou 21’ (PG) and ‘Yuzhui’ (YZ)) were used to compare the lipid oxidation characteristics (peroxide value, p-anisidine value and conjugated diene value), fatty acid profiles and major active components (squalene, carotenoids and tocopherols) under oxidation condition at 60 °C for 40 days, in addition, the molecular structure changes in the three hazelnut oils were monitored by Raman spectroscopy. The lipid oxidation of the three hazelnut oils had similar tendencies, and the oxidation rate was slower in the early stage and faster in the later stage. Polyunsaturated fatty acids (PUFAs) tended to decrease mainly due to the decrease in linoleic acid. LZ had higher contents of tocopherol, carotenoids and PUFAs than the other varieties, while YZ owned the highest content of squalene. Tocopherol and carotenoids of the three hazelnut oils showed easy loss, while squalene was relatively stable. Raman spectroscopy can effectively indicate the degree of oxidation and carotenoid levels of hazelnut oil. This study can provide a scientific basis for variety selection in planting and utilisation of active ingredients for the hazelnut industry.     

Acidified Sodium Chlorite as an Alternative to Chlorine for Elimination of Salmonella on Alfalfa Seeds

ABSTRACT:  The health and environmental hazard associated with the use of chlorine for food processing has been documented previously. This study was conducted to determine if acidified sodium chlorite (ASC) could be used to replace calcium hypochlorite (Ca[OCl]₂) for disinfection of alfalfa seeds. Contaminated seeds containing approximately 1.5 × 10⁷ CFU/g of Salmonella were treated with ASC or Ca(OCl)₂ at different concentrations and for different periods of time. Results showed that the efficacy of ASC and Ca(OCl)₂ for elimination of Salmonella on contaminated seeds could be improved greatly by extending the treatment time from the traditional 15 to 45 min. Treatment of seeds with 800 ppm of ASC for 45 min reduced the number of Salmonella by 3.9 log units, approximately 1.2 log units higher than that treated with 20000 ppm of Ca(OCl)₂. Treatment of seeds with a lower concentration (100 to 400 ppm) of ASC for 45 min reduced the number of Salmonella by 1.3 to 2.2 log units. Soaking alfalfa seeds in 800 ppm of ASC for 45 min did not affect seed germination. However, soaking seeds in 20000 ppm of Ca(OCl)₂ for 45 min reduced seed germination by 20%. Unlike Ca(OCl)₂, antimicrobial efficiency of ASC was not affected by pre-exposure to alfalfa seeds. Data presented also showed that Salmonella on newly inoculated seeds that had been stored at 4 °C for less than 7 d were more sensitive to sanitizer treatment than those on seeds that had been stored for 4 wk or longer.     

ACIDIFIED SODIUM CHLORITE, TRISODIUM PHOSPHATE AND POPULATIONS OF CAMPYLOBACTER JEJUNI ON CHICKEN BREAST SKIN

The present study was designed to determine the effects of acidified sodium chlorite (ASC) and trisodium phosphate (TSP) antimicrobial treatments. Chicken skin samples inoculated with Campylobacter jejuni ATCC 33291 and C. jejuni pc10 (isolated in our laboratory from chicken carcasses) were separately dipped into sterile tap water (control), 0.1% ASC, 10% TSP, 0.1% ASC followed by 10% TSP and 10% TSP followed by 0.1% ASC for 15 s at 25 ± 1C. Campylobacter jejuni counts and pH values were determined after 0, 1, 3 and 5 days of storage at 4 ± 1C. On day 0, reductions were between 1.1–2.5 log for C. jejuni ATCC 33291 and 1.4–2.4 log for C. jejuni pc10, while the reduction effects of all antimicrobials increased (P < 0.001) during the storage period and the bacterial counts reached undetectable levels (<1.0 × 10² cfu/g) on day 5 of storage at 4 ± 1C. The results of this study suggest that introduction of the antimicrobial treatments ASC, TSP and ASC followed by TSP into poultry processing systems could provide an added measure of safety.     

Effect of Treating of Squid with Sodium Chloride in Combination with Oxidising Agent on Bleaching,Physical and Chemical Changes During Frozen Storage

Pink discolouration is a problem faced in the squid processing industry, and some treatments have been implemented to tackle such a problem. The study aimed to elucidate the impact of NaCl in combination with oxidising agents on the quality changes of squid during frozen storage. The effects of treatment of pink squid using 3% (w/v) NaCl solution containing oxidising agents (0.05–0.5% (w/v) H₂O₂ or 0–10 ppm NaOCl) on colour and chemical and physical changes of squid during frozen storage were investigated. The lowest decreases in a*, b* values, ∆E* and ∆C* of squid were obtained with the treatment using 3% NaCl solution containing 0.5% H₂O₂. Nevertheless, NaOCl (0–10 ppm) had no impact on a* and b* values. During frozen storage at −18 °C for 10 weeks, fresh squid, pink squid samples without and with treatments with 3% NaCl solution containing 0.5% H₂O₂ had no changes in a* and b* values during frozen storage. Nevertheless, thiobarbituric acid reactive substances value, disulphide bond content, thaw drip and shear force were more pronounced in treated pink squid, compared with pink squid without treatment (control) and fresh squid, respectively, during the extended storage (p < 0.05). Higher denaturation and aggregation of muscle proteins during frozen storage were observed in treated pink squid than that without treatment and fresh squid, respectively. Therefore, pink squid treated with oxidising agent was prone to protein aggregation and denaturation during the extended frozen storage, though it could lower the pink colour. Therefore, fresh squid without treatment using oxidising agent is recommended for production of frozen squid with negligible loss in quality during extended storage.     

Efficacy of chlorine and peroxyacetic acid on reduction of natural microflora, Escherichia coli O157:H7, Listeria monocyotgenes and Salmonella spp. on mung bean sprouts

Sprouts-related outbreaks have risen due to increased raw sprouts consumption. To minimize such cases, chemical sanitations are applied. While chlorine is commonly used, concerns with its effectiveness and health implication have prompted researchers to seek alternatives. Peroxyacetic acid (PAA) has shown efficacy in inactivating foodborne pathogens on fresh vegetables, and hence could be considered as an alternative. Thus, the objective of this study was to compare the efficacy of chlorine and PAA in inactivating Escherichia coli O157:H7, Listeria monocytogenes, Salmonella spp., and natural microflora on mung bean sprouts. Resistance of non- and acid-adapted pathogens to these sanitizer treatments was also evaluated. Un-inoculated and inoculated sprouts were treated with chlorine at 106, 130 and 170 ppm and PAA at 25, 51 and 70 ppm for 90 and 180 s at room temperature. Overall, the greater log reductions were obtained with the increase in the sanitizer concentration. For 180 s, chlorine treatment at 170 ppm reduced 2.0, 1.3, 1.5, 0.9-logs and PAA treatment at 70 ppm resulted in 2.3, 1.8, 2.1, 1.1-log reductions for non-adapted E. coli O157:H7, L. monocytogenes, Salmonella spp., and natural microflora, respectively. These results revealed that the efficacy of PAA was significantly better than or similar to that of chlorine. For acid-adapted cells, these sanitizer treatments were less effective with the ranges of 1.0–1.2-log reductions for chlorine and 1.1–1.6-log reductions for PAA compared to non-adapted cells, indicating that acid-adapted cells were more resistant to the sanitizing treatment. These data suggest that PAA may replace chlorine in the disinfection of mung bean sprouts and that acid-adapted pathogens should be used to design an effective sanitizing strategy.     

Mycoflora and Aflatoxin Content of Hazelnuts,Walnuts, Peanuts,Almonds and Roasted Chickpeas (LEBLEBI) Sold in Turkey

In this study, 28 hazelnuts, 24 walnuts, 18 peanuts, 13 almonds, and 11 roasted chickpeas (leblebi) were analyzed for aflatoxin contamination using thin layer chromatography (TLC). Aflatoxin was found in 26 of 94 samples (27.66%) at concentrations ranging from 1 to 113 ppb. Detectable levels of aflatoxin were 33.4 ppb in hazelnuts, 22.1 ppb in walnuts, 43.0 ppb in peanuts, 7.4 ppb in almonds, and 1.7 ppb in roasted chickpeas. The highest level of aflatoxin was 113 ppb in a single hazelnut sample. Aspergillus and Penicillium species were frequently determined in all the samples.     

Acidified sodium chlorite as an alternative to chlorine to control microbial growth on shredded carrots while maintaining quality

Shredded carrots are particularly susceptible to microbial growth and quality deterioration as a result of a large cut surface area to mass ratio. Acidified sodium chlorite (ASC) in the concentration range 500–1200 µL L^?1 has been shown to have stronger efficacy against pathogens and spoilage bacteria than chlorine and does not form carcinogenic products. However, ASC in this concentration range aggravates tissue damage. The objective of this study was to optimize ASC treatment parameters to balance antimicrobial activity with quality retention of shredded carrots. Shredded carrots were immersed for either 1 min in 100, 250 or 500 µL L^?1 ASC solutions or 2 min in 200 µL L^?1 chlorine or water (control). Treated samples were spin‐dried and packaged in polypropylene bags and stored at 5 °C for up to 21 days. Carrots were evaluated at 7‐day intervals for visual appearance, package atmosphere composition (O₂ and CO₂), product firmness, tissue electrolyte leakage and pH. The microbial growth, including total aerobic bacterial counts, total coliforms/Escherichia coli, yeast and mold counts and lactic acid bacterial counts on the products was also determined. Treatments with all concentrations of ASC reduced the aerobic bacterial counts, coliform/E. coli counts, yeast mold and counts and lactic acid bacterial populations by 1.2–2.0 log cfu g^?1 when compared with the water‐washed and unwashed samples. During storage, unwashed samples had a sharp increase in lactic acid bacterial populations accompanied by a sharp decline in pH readings and rapid loss in firmness and tissue integrity; samples washed with 100 µL L^?1 ASC maintained the best overall visual quality, accompanied by the retention of tissue integrity and firmness. Therefore, 100 µL L^?1 was determined as the optimum concentration of ASC for maintaining overall quality and firmness, inhibiting microbial growth and prolonging the shelf‐life of shredded carrots. Copyright © 2006 Society of Chemical Industry     

Effects of potassium lactate,sodium metasilicate,peroxyacetic acid,and acidified sodium chlorite on physical,chemical, and sensory properties of ground beef patties

Beef trimmings were treated with 3% potassium lactate (KL), 4% sodium metasilicate (NMS), 0.02% peroxyacetic acid (PAA) or 0.1% acidified sodium chlorite (ASC) or left untreated (CON). Beef trimmings were ground, pattied, and sampled for 7 days. Under simulated retail display, instrumental color, sensory characteristics, TBARS, pH, and Lee–Kramer shear force were measured to evaluate the impact of the treatments on the quality attributes. The NMS and PAA patties were redder (a^∗, P < 0.05) than CON on days 0–3. Panelists found KL, NMS, PAA, and ASC patties to have less (P < 0.05) or similar (P > 0.05) off odor to CON on days 0–3. The NMS and PAA treated patties had lower (P < 0.05) lipid oxidation than the CON at days 0, 3, and 7. Therefore, KL, NMS, PAA, and ASC treatments on beef trimmings can potentially improve or maintain quality attributes of beef patties.