Acidified Sodium Chlorite Treatment Research Articles

Revealing spatial distribution and accessibility of cell wall polymers in bamboo through chemical imaging and mild chemical treatments

Understanding the distribution and accessibility of polymers within plant cell walls is crucial for addressing biomass recalcitrance in lignocellulosic materials. In this work, Imaging Fourier Transform Infrared (FTIR) and Raman spectroscopy, coupled with targeted chemical treatments, were employed to investigate cell wall polymer distribution in two bamboo species at both tissue and cell wall levels. Tissue-level Imaging FTIR revealed significant disparities in the distribution and chemical activity of cell wall polymers between the fibrous sheath and fibrous strand. At the cell wall level, Imaging Raman spectroscopy delineated a distinct difference between the secondary wall and intercellular layer, with the latter containing higher levels of lignin, hydroxycinnamic acid (HCA), and xylan, and lower cellulose. Mild acidified sodium chlorite treatment led to partial removal of lignin, HCA, and xylan from the intercellular layer, albeit to a lesser extent than alkaline treatment, indicating susceptibility of these polymers to chemical treatment. In contrast, lignin in the secondary wall exhibited limited reactivity to acidified sodium chlorite but was slightly removed by alkaline treatment, suggesting stable chemical properties with slight alkaline intolerance. These findings provide valuable insights into the inherent design mechanism of plant cells and their efficient utilization.

Isolation of Cellulose from Wheat Straw Using Alkaline Hydrogen Peroxide and Acidified Sodium Chlorite Treatments: Comparison of Yield and Properties

Environmental concerns due to excessive use of synthetic or petroleum-based materials have encouraged scientists to develop novel, sustainable, and multifunctional material using abundant lignocellulosic biomass. In this work, a study was conducted on the isolation of cellulose from wheat straw using two different methods: acidified sodium chlorite and alkaline hydrogen peroxide. A comparative study was carried out based on the yield and properties of extracted cellulose. The final product (after treatments) was characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA) for the identification of properties. Both the treatments isolated pure white color cellulose. However, the yield of cellulose isolated through acidified sodium chlorite treatment (81.4%) was higher than alkaline hydrogen peroxide treatment (79%). Moreover, no huge difference was observed in the crystallinity and thermal properties of extracted cellulose.

Validation of Interventions on Raw Ground Beef Components; Cheek Meat and Weasand

ObjectivesInterventions are commonly used to treat carcasses to reduce microbial loads, but little information is available on the use of these interventions on cheek meat and weasand, which can be used as raw ground beef components. Due to their anatomical location, they could have a high risk of contamination. The objective of this study was to determine the efficacy of 2 antimicrobial interventions strategies; 4% lactic acid (LA), and 1,000 ppm Acidified Sodium Chlorite (ASC), to reduce pathogens in raw ground beef components; cheek meat and weasand.Materials and MethodsThe experiment was a randomized complete split-plot design with individual Cheek meat (N = 36) and Weasand (N = 36), defined as experimental units. The 2 components were challenged with a 3-strain cocktail mixture of each of the pathogen; Escherichia coli O157: H7 (Strains 944, 966, and 922) STECS (nonO157 STEC serogroups; 045, 0145, and 0121) and Salmonella (Typhimurium, Enteriditis, and Newport) 7.1, 7.2, and 6.8 log10 CFU/ml respectively, for 20 min. All the strains were obtained from the Texas Tech University Food Microbiology Laboratory stock collection (Lubbock). For every pathogen, a total of 12 units of each component were used. The units of each component inoculated with a pathogen were further divided into 4 subgroups, each group consisting of 3 pieces; I) Inoculated but nontreated (used to determine recovery of pathogens), ii) Ambient water (CTRL), iii) 4% lactic acid (LA) and iv) Acidified Sodium Chlorite (ASC). On d 0, the interventions consisting; Ambient water (pH = 6.87), 4% lactic acid (pH = 2.03) and Acidified Sodium Chlorite (pH = 2.91, 1,000 ppm). were sprayed onto the surface of the product at room temperature, as they move down the belt, inside a 6-nozzle trim-sanitizing spray. Following treatment, 50 cm2 of each sample was swabbed by using 10 mL Buffered Peptone Water (BPW) swabs and sterile template and subjected to bacterial enumeration on thin-overlaid selective media. These samples were held at 4°C, for 24 h, separate area was swabbed and enumerated. Data were analyzed in R-Studio (version 3.3.1).ResultsOn d 0, LA reduced E. coli, STECS and Salmonella in cheek meat and weasand on average by 0.90, 0.93, and 0.89 log10 CFU/cm2 respectively, when compared with the initial level of the pathogens in inoculated and non-treated samples. Similarly, ASC reduced pathogens on average by 0.79, 0.87, and 0.78 log10 CFU/cm2, respectively. Samples treated with ambient water gave lower surface counts of the pathogens when compared to untreated samples, however, the reduction was not significant. Both LA and ASC treatment maintained bacterial reduction even after 24 h.ConclusionThe LA and ASC treatments can be used as intervention alternatives for cheek meat and weasand, as these components can potentially become a high-risk source of contamination.

Cellulose Fiber Isolation and Characterization from Sweet Blue Lupin Hull and Canola Straw

In this study, cellulose fibers were removed from crop by-products using a combination of sodium hydroxide treatment followed by acidified sodium chlorite treatment. The objective was to obtain high recovery of cellulose by optimizing treatment conditions with sodium hydroxide (5–20%, 25–75 °C and 2–10 h) followed by acidified sodium chlorite (1.7%, 75 °C for 2–6 h) to remove maximum lignin and hemicellulose, as well as to investigate the effect of lignin content of the starting materials on the treatment efficiency. Samples were characterized for their chemical composition, crystallinity, thermal behavior and morphology to evaluate the effects of treatments on the fibers’ structure. The optimum sodium hydroxide treatment conditions for maximum cellulose recovery was at 15% NaOH concentration, 99 °C and 6 h. Subsequent acidified sodium chlorite treatment at 75 °C was found to be effective in removing both hemicellulose and lignin, resulting in higher recovery of cellulose in lupin hull (~ 95%) and canola straw (~ 93%). The resultant cellulose fibers of both crop by-products had increased crystallinity without changing cellulose I structure (~ 68–73%). Improved thermal stabilities were observed with increased onset of degradation temperatures up to 307–318 °C. Morphological investigations validated the effectiveness of treatments, revealing disrupted cell wall matrix and increased surface area due to the removal of non-cellulosics. The results suggest that the optimized combination of sodium hydroxide and acidified sodium chlorite treatments could be effectively used for the isolation of cellulose fibers from sweet blue lupin hull and canola straw, which find a great number of uses in a wide range of industrial applications.

Interaction of Acidified Sodium Chlorite with Dietary Energy and Feed Enzymes in Broiler Chicken

In today's world, there is need to sanitize feeds and enhance energy utilization from available feed resources in poultry. So the present experiment was conducted to study the interaction of acidified sodium chlorite (ASC) with dietary energy and feed enzymes in broiler chicken. Twelve diets with two energy levels (2800 and 3000 kcal/kg) each treated with 0, 100 and 250 ppm of ASC and with or without addition of feed enzymes (30 g per quintal) were formulated following a 2×2×3 factorial design. Each dietary treatment was offered to respective group, having 4 replicates of 8 chicks in each. Results revealed that feed energy level accrued significant variation (P<0.001) in live weight and the birds which received 3000 kcal/kg energy had significantly (P<0.001) higher body weight. The feed intake was not affected by either the level of dietary energy or exogenous enzyme supplementation but ASC level at 250 ppm suppressed feed intake. The pH and water holding capacity of meat samples was similar amongst all the treatment groups, however, ASC treatment increased thio-barbituric acid reactive substance value (P<0.001) in a dose dependent manner. Higher dietary energy also increased the weight of spleen and improved humoral immunity. From this study, it may be concluded the zoo-technical performance and immunocompetence was significantly better in birds offered higher energy feed and apparently no interaction was observed between ASC, dietary energy level and feed enzymes. On the other hand oxidative stability of meat was compromised at higher level of ASC.

Interaction of oxidative feed sanitizer with dietary methionine on growth and immune-responsiveness of broiler chickens

Acidified sodium chlorite (ASC), a well known sanitizer, reduces microbial load and improves energy bioavailability from fiber/lignin rich feedstuffs. However, ASC also reacts with sulphur containing amino acid methionine, the first limiting amino acid in maize-soy based diet. So the present experiment was conducted to assess the interaction of ASC with dietary methionine in terms of growth performance, meat quality and immune- competence of broiler chicks. A basal diet was formulated without methionine supplementation (otherwise adequate in all nutrients) and then treated with 3 levels of ASC (0, 100 and 250 ppm). Each ASC treated basal diet was supplemented without or with DL-methionine to meet 100 and 120% of NRC requirement of methionine in a 3 × 3 factorial design. Day-old broiler chicks (288) were divided into 36 groups of 8 chicks each and each dietary treatment was offered to 4 replicated groups. At 6 weeks of age, methionine supplementation produced significant increase in live body weight, weight gain and feed conversion ratio. Among meat quality parameters, thiobarbituric acid reactive substance value increased significantly upon ASC treatment and reduced by methionine supplementation at 120%. Among cut-up parts, neck yield increased significantly with increased level of methionine. Increase in methionine level also produced improvement in humoral and cell mediated immunity. Thus, it may be concluded that ASC treatment deteriorated oxidative stability of meat while methionine supplementation improved broiler performance, meat quality and immunocompetence

Reduction of Surrogates for Escherichia coli O157:H7 and Salmonella during the Production of Nonintact Beef Products by Chemical Antimicrobial Interventions

The efficacy of chemical antimicrobials for controlling Escherichia coli O157:H7 and Salmonella during production of marinated nonintact beef products was evaluated using nonpathogenic surrogates. Boneless beef strip loins were inoculated with either approximately 5.8 or 1.9 log CFU/cm(2) (high and low inoculation levels, respectively) of nonpathogenic rifampin-resistant E. coli. Inoculated strip loins were chilled at 2°C for 24 h, vacuum packaged, and aged for 7 to 24 days at 2°C. After aging, strip loins received no treatment (control) or one of five antimicrobial spray treatments: 2.5% L-lactic acid (pH 2.6), 5.0% L-lactic acid (pH 2.4), 1,050 ppm of acidified sodium chlorite (pH 2.8), 205 ppm of peroxyacetic acid (pH 5.2), or tap water (pH 8.6). Mean application temperatures were 53, 26, 20, and 18°C for lactic acid, water, peroxyacetic acid, and acidified sodium chlorite treatments, respectively. Treated and control strip loins were vacuum tumbled in a commercial marinade. Samples were collected throughout the experiment to track the effects of antimicrobial treatment and processing on inoculated surrogates. For high-inoculation strip loins, the 5.0% L-lactic acid treatment was most effective for reducing surrogates on meat surfaces before marination, producing a 2.6-log mean reduction. Peroxyacetic acid treatment resulted in the greatest reduction of surface-located surrogate microorganisms in marinated product. Water treatment resulted in greater internalization of surrogate microorganisms compared with the control, as determined by enumeration of surrogates from cored samples. Producers of nonintact beef products should focus on use of validated antimicrobial sprays that maximize microbial reduction and minimize internalization of surface bacteria into the finished product.

Effect of Acidified Sodium Chlorite Treatment of Feedstuffs on Nitrogen and Amino Acid Digestibility in Poultry

The present study was conducted to study the effect of Acidified sodium chlorite (ASC) treatment on nitrogen utilization and amino acid digestibility in caecectomised white leghorn cockerels. Feed ingredients viz. soybean meal, meat cum bone meal and sunflower meal were treated with 80 ppm of ASC either in dry or wet form and 30 g of these ingredients were forced fed to caecectomised white leghorn cockerels, maintained in individual cages. Fecal material was collected (up to 24 h) and analyzed for dry matter, nitrogen, uric acid and amino acid content. Results revealed that ASC treatment of feedstuffs numerically improved their dry matter metabolizability without any appreciable variation in nitrogen and amino acids bioavailability. Thus it may be concluded that ASC treatment (80 ppm) of feedstuffs has no apparent effect on nitrogen and amino acid digestibility in poultry.

Extraction and Characterization of Cellulose Nanofibers from Phyllostachys nidularia Munro via a Combination of Acid Treatment and Ultrasonication

In this work, α-cellulose was extracted from Phyllostachys nidularia Munro using an acidified sodium chlorite treatment followed by alkali treatments, and cellulose nanofibers (CNFs) were then extracted from α-cellulose via the combination of sulfuric acid (64 wt%) and low-intensity ultrasonication. The results showed that superior CNFs were successfully extracted and their diameters were in the range of 5 to 20 nm. Fourier transform infrared spectroscopy (FTIR) suggested that a majority of the hemicellulose and lignin were removed from the original material and that the chemical constituents of α-cellulose and CNFs were similar. X-ray diffraction (XRD) analysis indicated that the relative crystallinity of CNFs was significantly increased to approximately 69.32% and all specimens presented a typical cellulose I crystal form. Thermogravimetric analysis (TGA) showed that the thermostability of the CNFs was greatly increased.

Enhanced bactericidal action of acidified sodium chlorite caused by the saturation of reactants.

Factors affecting the antibacterial action of acidified sodium chlorite (ASC), a widely used disinfectant, have not been determined. This study investigated the significant factors suggesting efficient production method to maximize bactericidal action of ASC. The effects of (i) preparation procedures (total three methods); (ii) initial concentrations of reactants: sodium chlorite (SC) and citric acid (CTA) (up to maximum solubility of each reactant) and (iii) final pH values (3·0 and 2·5) to the bactericidal action of ASC were investigated with a fixed final concentration of SC (10 ppm) using various foodborne pathogens (Escherichia coli O157:H7, Listeria monocytogenes, Salmonella Typhimurium and Staphylococcus aureus). The antimicrobial compounds produced and the bactericidal effects depended on the preparation procedure and the initial concentrations of the reactants. The ASC prepared by premixing highly concentrated reactants (in particular > 40%) followed by dilution (dilution after reaction, DAR) was more effective in inactivating foodborne pathogens, and it produced higher antimicrobial compound (Cl(2) and ClO(2)) yields than the other procedures. A 5-min treatment with ASC, produced using the other procedures, resulted in a reduction of < 3·5 log CFU ml(-1) (Gram positive = 0·18-0·78; Gram negative = 0·03-3·49 log CFU ml(-1)), whereas ASC produced with the DAR procedure using the saturated reactants completely inactivated all of the test pathogens within 5 min without recovery (initial concentration = 6·94-7·08 log CFU ml(-1)). The ASC production with the DAR procedure using the saturated reactants maximizes both the antimicrobial compound yields and bactericidal effects of the ASC solutions. This study will contribute to increase the efficiency of ASC treatments for disinfections reducing the effective SC concentrations for industrial use.

Ultrasound Enhanced Sanitizer Efficacy in Reduction of Escherichia coli O157 : H7 Population on Spinach Leaves

The use of ultrasound to enhance the efficacy of selected sanitizers in reduction of Escherichia coli O157 : H7 populations on spinach was investigated. Spot-inoculated spinach samples were treated with water, chlorine, acidified sodium chlorite (ASC), peroxyacetic acid (POAA), and acidic electrolyzed water with and without ultrasound (21.2 kHz) for 2 min at room temperature. The effects of ultrasound treatment time and acoustic energy density (AED) were evaluated at an ASC concentration of 200 mg/L. The effect of ASC concentration, with a fixed AED of 200 W/L, was also examined. Microbial analysis indicated that ASC reduced E. coli O157 : H7 population by 2.2 log cycles over that of water wash, while the reduction from other sanitizers was about 1 log cycle. Ultrasonication significantly enhanced the reduction of E. coli cells on spinach for all treatments by 0.7 to 1.1 log cycle over that of washes with sanitizer alone. An increase in the ASC concentration enhanced the efficacy of the combined treatment of ASC and ultrasonication, especially at ASC concentrations of < 300 mg/L. Increasing the ultrasound treatment time from 0 to 4 min and AED from 0 to 500 W/L were both effective in increasing the effectiveness of the ASC and ultrasound combined treatments. In addition, E. coli O157 : H7 inoculated on the underside of spinach leaves (rough side) were more difficult to remove than those inoculated on the upper side (smooth side).

Antimicrobial Effect of Acidified Sodium Chlorite (ASC) on Whole Croaker

The antimicrobial effect of acidified sodium chlorite (ASC) solution on whole croaker skin was evaluated. Whole croaker skin was treated with ASC (50, 100, 200, 400, and 600 ppm) and distilled water. After 10-minute exposure to 600 ppm ASC, 8% of Gram-negative bacteria survived on the whole croaker sample. Treatment with 50 ppm ASC eliminated all coliforms in the initial load. Immersion treatment with 600 ppm ASC resulted in 1.3 log CFU/㎠ greater kill of the initial mesophile loads of control (2.8 log CFU/㎠) than distilled water. Fifty ppm ASC solution produced a 1.6-log reduction of psychrotrophic bacteria. ASC treatment was an effective method for reducing naturally occurring microflora on whole croaker skin.

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.

Effect of the sequential treatment of 1-methylcyclopropene and acidified sodium chlorite on microbial growth and quality of fresh-cut cilantro

This study investigated the effects of 1-methylcyclopropene and sanitizer (acidified sodium chlorite or sodium hypochlorite), treated alone or in combination, on microbial growth and quality of packaged fresh-cut cilantro ( Coriandrum sativum L.). Cilantro bunches were treated with 1.5 mg L −1 1-methylcyclopropene or air for 18 h at 10 °C. The samples were then cut and washed in tap water, 100 mg L −1 sodium hypochlorite, or 100 mg L −1 acidified sodium chlorite solution for 1 min. The washed cilantro leaves were centrifugally dried, packaged with 29.2 pmol s −1 m −2 Pa −1 oxygen transmission rate film, and stored at 5 °C for 14 d. Results indicated that 1-methylcyclopropene significantly ( P < 0.0001) delayed the decrease in O 2 and accumulation of CO 2 partial pressures in the headspace of sample packages. Acidified sodium chlorite application significantly reduced initial coliform/ Escherichia coli counts ( P < 0.001), and reduced decay rate at the end of storage ( P < 0.05). A combination treatment of 1-methylcyclopropene and acidified sodium chlorite, followed by acidified sodium chlorite treatment alone, maintained the lowest decay rates and the highest overall quality scores at the end of storage.

Effect of acidified sodium chlorite treatment on chicken carcases processed in South Australia

A trial on the effectiveness of acidified sodium chlorite (ASC) on Salmonella and Campylobacter was undertaken on chicken carcases after they exited the screw chiller of a commercial premises in Adelaide, Australia. On untreated carcases mean log 10 total viable count (25 °C) was 2.78/cm 2 compared with 1.23/cm 2 on treated carcases. Prevalence of E. coli, Salmonella and Campylobacter was 100%, 90% and 100% respectively, on untreated carcases and 13%, 10% and 23% respectively, on treated carcases. The distributions of E. coli, Salmonella and Campylobacter (mean log 10 of positive samples) from untreated carcases were 1.55, − 1.80 and 1.59/cm 2 respectively, and − 0.64, − 1.85 and − 2.21/cm 2 respectively, on treated carcases. On untreated carcases S. Sofia and S. Infantis were isolated from 73% and 37% of carcases, respectively; only S. Sofia was isolated from treated carcases. The significant reductions in both prevalence and concentration demonstrated in the present trial indicate that ASC is a risk management option immediately available to the poultry industry.

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

AbstractShredded 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

Inhibition of Escherichia coli O157:H7, Listeria monocytogenes and Staphylococcus aureus on sliced roast beef by cetylpyridinium chloride and acidified sodium chlorite

The effects of 0.5% cetylpyridinium chloride (CPC), 0.12% acidified sodium chlorite (ASC) and a mix of equal volume of the two (0.25% CPC-0.06% ASC) on Escherichia coli O157:H7, Listeria monocytogenes and Staphylococcus aureus were evaluated on inoculated sliced roast beef. The antimicrobial agents were, respectively, sprayed on the beef surfaces and tray absorbent pads, and samples were stored at 4 °C for 10 days (d). At 0 d, L. monocytogenes and S. aureus were reduced to undetectable levels in 2 h after spraying with CPC. CPC–ASC treatment reduced E. coli O157:H7, L. monocytogenes and S. aureus by 4.07, 6.37 and 4.32 log cfu/cm 2, respectively, at 0 d. ASC treatment reduced the population of E. coli O157:H7 by 6.09 log cfu/cm 2 at 10 d. CPC treatment caused a slight discoloration and ASC-treated beef surfaces demonstrated the lowest redness and highest lightness. The grey colour and off-odour were significant in the ASC-treated beef samples, while CPC-treated samples demonstrated less off-odor and brown colour from 0 to 4 d. Based on our results, it appears that the application of CPC on sliced roast beef can extend the shelf-life of the product without impairing its quality.

Acidified Sodium Chlorite Treatment for Inhibition of Listeria monocytogenes Growth on the Surface of Cooked Roast Beef

The effects of acidified sodium chlorite (ASC) against Listeria monocytogenes on the surface of cooked roast beef were investigated. L. monocytogenes, strain V7, serotype 1/2a, was inoculated at numbers of 6.0 log CFU/g onto 5-g cubes of cooked regular or spicy roast beef. The samples were allowed to air dry for 1 h. The cooked roast beef samples were dipped into ASC or sprayed with ASC solutions of 250, 500, 750, or 1,000 ppm, then placed in bags with or without a vacuum and refrigerated at 4°C. L. monocytogenes counts were determined after 0, 7, 14, 21, and 28 days of storage by spread plating roast beef samples onto Oxford agar plates that were incubated at 37°C for 48 h. At day 28, the number of L. monocytogenes on the ≥500 ppm ASC-treated spicy roast beef samples had count reductions that were >4.0 log CFU/g, whereas the same concentrations of ASC-treated regular roast beef samples had approximately a 2.5 log CFU/g reduction in L. monocytogenes counts when compared with the untreated samples. No significant differences (P > 0.05) were observed in L. monocytogenes counts between the vacuum- or nonvacuum-packaged ASC-treated cooked roast beef samples. Sensory evaluation showed no significant differences (P > 0.05) between ASC-treated and untreated roast beef. ASC can be used as a processing aid in the form of a dip or spray treatment to control L. monocytogenes on the surface of cooked roast beef.

Efficacy of Acidified Sodium Chlorite Treatments in Reducing Escherichia coli O157:H7 on Chinese Cabbage

Efficacy of acidified sodium chlorite for reducing the population of Escherichia coli O157:H7 pathogens on Chinese cabbage leaves was evaluated. Washing leaves with distilled water could reduce the population of E. coli O157:H7 by approximately 1.0 log CFU/g, whereas treating with acidified chlorite solution could reduce the population by 3.0 log CFU/g without changing the leaf color. A similar level of reduction was achieved by washing with sodium chlorite solution containing various organic acids. However, acidified sodium chlorite in combination with a mild heat treatment reduced the population by approximately 4.0 log CFU/g without affecting the color, but it softened the leaves. Moreover, the efficacy of the washing treatment was similar at low (4°C) and room (25°C) temperatures, indicating that acidified sodium chloride solution could be useful as a sanitizer for surface washing of fresh produce.

Decreased Dosage of Acidified Sodium Chlorite Reduces Microbial Contamination and Maintains Organoleptic Qualities of Ground Beef Products

Acidified sodium chlorite (ASC) spray was evaluated at decreased dosages and application rates to determine its efficacy for reducing bacterial contamination on boneless beef trimmings used for production of raw ground beef products while maintaining desirable consumer qualities in the finished ground beef products. Two different applications of ASC (600 ppm applied at a rate of 1.3 oz/lb and 300 ppm applied at a rate of 1 oz/lb) were used to treat boneless beef trimmings before grinding. The effect of ASC treatment on 50/50 lean beef trimmings was greater than on 90/10 trimmings. ASC at 600 ppm reduced both the aerobic plate counts (APC) and Enterobacteriaceae counts (EBC) by 2.3 log CFU/g on 50/50 trimmings, whereas treatment with 300 ppm ASC reduced APC and EBC of 50/50 trimmings by 1.1 and 0.7 log CFU/g, respectively. Ground beef formulations of 90/10 and 73/27 were produced from the treated boneless beef trim and packaged in chubs and in modified atmosphere packaging. The efficacy of ASC spray treatment to inhibit APC and EBC over the shelf life of each ground beef product was monitored. The APC and EBC in ground beef chubs were reduced by 1.0 to 1.5 log CFU/g until day 20. The APC and EBC for products in modified atmosphere packaging were reduced 1.5 to 3.0 log CFU/g throughout their shelf life. Both decreased dosages of ASC were equally effective on 90/10 lean ground beef, but the 300 ppm ASC treatment was slightly better at reducing the EBC of 73/27 ground beef. The organoleptic qualities (color, odor, and taste) of the ground beef products treated with 300 ppm ASC were found to be superior to those treated with 600 ppm ASC. Our results indicated that decreased dosages of ASC reduce contamination and lengthen the shelf life of ground beef. Furthermore, the 300 ppm ASC treatment reduced bacterial counts while maintaining desirable organoleptic ground beef qualities.