Comparison of Generally Recognized as Safe Organic Acids for Disinfecting Fresh-cut Lettuce

ABSTRACTIn this study, we aimed to determine the organic acids (acetic, lactic, citric, malic, propionic, succinic, and tartaric acids; 1% and 0.5%, w/w or v/v) that were most effective for fresh-cut lettuce disinfection based on analysis of quality (i.e., color, electrolyte leakage, and sensory quality) and microbial examination. The results showed that these acids did not negatively affect the color quality (i.e., L*, a*, b*, whiteness index, and sensory color). Additionally, 0.5% lactic acid led to the lowest electrolyte leakage (0.83%), which was not significantly different (p > 0.05) from that of distilled water (0.46%). Lactic acid (1%) did not affect the sensory quality and led to the highest microbial reduction (1.45 log reduction in aerobic plate counts [APCs]; 2.31 log reduction in molds and yeasts [M&Y]) and was therefore recommended as the primary choice for lettuce disinfection. Malic acid (0.5%), with a 1.07% electrolyte leakage rate, 0.73 log reduction in APCs, and 1.40 log reduction in M&Y, was better than the other six acids (0.5%) and was recommended as a pH regulator and a potential synergistic agent for oxidizing sanitizers. Acetic acid (1%) negatively affected the sensory quality and led to the highest electrolyte leakage (2.90%). Microbial analysis showed that propionic acid (0.5% and 1%) was ineffective for disinfection of lettuce (p > 0.05); thus, acetic and propionic acids were not recommended. Our results provide insights into the choice of sanitizers and formula design in food safety.IMPORTANCESince chlorine is forbidden in several countries, generally recognized as safe organic acids are used in minimal processing industries and in household sanitizers. The disinfection efficacy of organic acids has been studied when used alone or with oxidizing sanitizers. However, since different antibacterial mechanisms, contact time, fresh produce, and concentration have been reported, the acids most effective for single fresh produce disinfection, especially that of lettuce, an important salad vegetable, are not known. Moreover, in developing countries, because of imperfections in field management, cold chain transportation, and minimal processing industry development, the demand for low-cost household sanitizers is greater than that for minimally processed fresh produce. In this work, microbial load in lettuce was determined after disinfecting with seven GRAS organic acids. The changes in quality were also determined. These results provide insights into the choice of minimal processing sanitizers and a formula design for household sanitizers.

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Efficacy of a Novel Sanitizer Composed of Lactic Acid and Peroxyacetic Acid against Single Strains of Nonpathogenic Escherichia coli K-12, Listeria innocua, and Lactobacillus plantarum in Aqueous Solution and on Surfaces of Romaine Lettuce and Spinach

Journal of Food Protection ◽

10.4315/0362-028x.jfp-11-110 ◽

2011 ◽

Vol 74 (9) ◽

pp. 1468-1474 ◽

Cited By ~ 19

Author(s):

KAI-LAI GRACE HO ◽

DIEGO A. LUZURIAGA ◽

KENNETH M. RODDE ◽

SHANNON TANG ◽

CUONG PHAN

Keyword(s):

Escherichia Coli ◽

Lactic Acid ◽

Lactobacillus Plantarum ◽

Ph Value ◽

Fresh Produce ◽

Microbial Reduction ◽

Listeria Innocua ◽

Peroxyacetic Acid ◽

Log Reduction ◽

K 12

A novel sanitizer composed of lactic acid and peroxyacetic acid (LA-PAA) was developed as an alternative to chlorinated water (CW) for fresh produce processing. Single strains of Lactobacillus plantarum, nonpathogenic Escherichia coli K-12, and Listeria innocua were used to demonstrate the microbial efficacy of LA-PAA. LA-PAA achieved a >7.8-log reduction of L. innocua and L. plantarum suspended in water at 4°C for 20 s, and LA, PAA, and CW achieved reductions of 0.4, 4.8, and 2.7 log, respectively. LA-PAA, when compared with LA, PAA, and CW, enhanced the reduction of L. innocua attached to romaine leaves by >2.2 log, and improved the removal of E. coli attached to spinach leaves by >2.4 log. The exponential improvement in the microbial efficacy of LA-PAA showed synergism between LA and PAA. LA-PAA microbial efficacy was inversely proportional to pH value and directly correlated with residence time and concentration. Despite an improvement in microbial reduction through the addition of surfactant to LA-PAA, the usage of surfactant in washing fresh produce was impeded by excessive foaming during actual processing. Effects of organic matter on the performance of LA-PAA were minimal. External sensory evaluations showed that LA-PAA had no negative effects on the quality of lettuce and tender leaves. Temperature-abuse studies demonstrated that LA-PAA reduced decay by ~50% when compared with CW. Overall, these results support the premise that LA-PAA has significant potential to be an alternative to CW for fresh produce processing.

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Organic acids produced by lactic acid bacteria (Leuconostocsp.) contribute to sensorial quality loss in modified-atmosphere-packed fresh-cut iceberg lettuce

Acta Horticulturae ◽

10.17660/actahortic.2016.1141.36 ◽

2016 ◽

pp. 289-296 ◽

Cited By ~ 3

Author(s):

M.J.M. Paillart ◽

J.M.B.M. van der Vossen ◽

E. Lommen ◽

E. Levin ◽

E.C. Otma ◽

...

Keyword(s):

Lactic Acid ◽

Lactic Acid Bacteria ◽

Organic Acids ◽

Modified Atmosphere ◽

Quality Loss ◽

Iceberg Lettuce ◽

Sensorial Quality ◽

Fresh Cut

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Dietitians’ Attitudes, Perceptions, and Usage Patterns For Fresh-cut Fruit and Vegetables

Canadian Journal of Dietetic Practice and Research ◽

10.3148/69.1.2008.7 ◽

2008 ◽

Vol 69 (1) ◽

pp. 7-13 ◽

Cited By ~ 3

Author(s):

Katherine A. Sanford ◽

Elizabeth M. Johnston ◽

Jennifer L. Porter ◽

Judith Lowe ◽

Debra M. Oxby

Keyword(s):

Nutritional Value ◽

Sensory Quality ◽

Fresh Produce ◽

Cost Benefit ◽

Fruit And Vegetables ◽

Nutrient Value ◽

Vegetable Products ◽

Usage Patterns ◽

Fresh Cut ◽

Nutrition Educators

Purpose: New fresh-cut fruit and vegetable products are being developed worldwide. Nutrition educators’ perceptions of these products were studied. Methods: Professional dietitians in Nova Scotia were asked to complete a questionnaire on their use of fresh-cut produce. The questionnaire also elicited their attitudes and perceptions about the convenience, taste/quality, nutrition/health benefits, cost, and safety of fresh-cut fruit and vegetables. Results: Sixty-three percent of respondents reported eating five to six servings of fruit and vegetables a day. This group most frequently consumed fresh-cut fruit as snacks or dessert, and vegetables in stir-fry dishes or salads or cooked with meals. In general, fresh-cut fruit and vegetables were perceived as convenient, safe, and nutritious. While approximately 50% of participants felt fresh-cut produce did not differ in taste from whole fresh produce, almost the same number considered whole fresh produce superior in taste. Conclusions: Dietitians have a generally positive perception of fresh-cut products; however, there is uncertainty about the nutritional value, cost/benefit, and use of the products. Dietitians require more information on the nutrient value of these products and on suggested alternative uses. Attention should be paid to developing fresh-cut products that have good sensory quality.

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Evaluation of Bactericidal Effects of Phenyllactic Acid on Escherichia coli O157:H7 and Salmonella Typhimurium on Beef Meat

Journal of Food Protection ◽

10.4315/0362-028x.jfp-19-217 ◽

2019 ◽

Vol 82 (12) ◽

pp. 2016-2022

Author(s):

RUISHENG ZHENG ◽

TONG ZHAO ◽

YEN-CON HUNG ◽

KOUSHIK ADHIKARI

Keyword(s):

Escherichia Coli ◽

Lactic Acid ◽

Salmonella Typhimurium ◽

Microbial Reduction ◽

Escherichia Coli O157 ◽

Phenyllactic Acid ◽

E Coli ◽

Log Reduction ◽

Beef Meat ◽

Bactericidal Effects

ABSTRACT Bactericidal effects of various concentrations of phenyllactic acid on Shiga toxin–producing Escherichia coli (STEC), including E. coli O157:H7, O26:H11, O103:H2, and O121:H19, and on Salmonella Typhimurium DT104 in pure culture and microplates assays were studied. Beef cuts were surface sprayed with phenyllactic acid or lactic acid for inactivation of E. coli O157:H7 and Salmonella Typhimurium. The 1.5% phenyllactic acid inactivated all inoculated E. coli O157:H7, O26:H11, O103:H2, and O121:H19 and Salmonella Typhimurium DT104 (>6-log reduction) within 1 min of contact at 21°C, whereas 1.5% lactic acid did not result in microbial reduction. Microplate assays (for STEC and Salmonella Typhimurium DT104 at 10 to 100 CFU per well) indicated that concentrations of 0.25% phenyllactic acid or 0.25% lactic acid inhibited the growth of STEC and Salmonella Typhimurium DT104 incubated at 37°C for 24 h. Treatment of beef with 1.5% lactic acid or 1.5% phenyllactic acid reduced E. coli O157:H7 by 0.22 and 0.38 log CFU/cm2, respectively, within 5 min and reduced Salmonella Typhimurium DT104 by 0.12 and 0.86 log CFU/cm2, respectively. When meat treated with 1.5% phenyllactic acid was frozen at −20°C, inactivation of E. coli O157 and Salmonella Typhimurium DT104 was enhanced by 1.06 and 1.46 log CFU/cm2, respectively. Thus, treatment of beef with 1.5% phenyllactic acid significantly reduced the population of E. coli O157:H7 and Salmonella. HIGHLIGHTS

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Protective Effects of Organic Acids on Survival of Escherichia coli O157:H7 in Acidic Environments

Applied and Environmental Microbiology ◽

10.1128/aem.72.1.660-664.2006 ◽

2006 ◽

Vol 72 (1) ◽

pp. 660-664 ◽

Cited By ~ 53

Author(s):

K. Bjornsdottir ◽

F. Breidt ◽

R. F. McFeeters

Keyword(s):

Escherichia Coli ◽

Lactic Acid ◽

Organic Acids ◽

Protective Effect ◽

Low Ph ◽

Ph Effects ◽

E Coli ◽

Cell Numbers ◽

Log Reduction ◽

Cell Counts

ABSTRACT Outbreaks of disease due to acid-tolerant bacterial pathogens in apple cider and orange juice have raised questions about the safety of acidified foods. Using gluconic acid as a noninhibitory low-pH buffer, we investigated the killing of Escherichia coli O157:H7 strains in the presence or absence of selected organic acids (pH of 3.2), with ionic strength adjusted to 0.60 to 0.68. During a 6-h exposure period in buffered solution (pH 3.2), we found that a population of acid-adapted E. coli O157:H7 strains was reduced by 4 log cycles in the absence of added organic acids. Surprisingly, reduced lethality for E. coli O157:H7 was observed when low concentrations (5 mM) of fully protonated acetic, malic, or l-lactic acid were added. Only a 2- to 3-log reduction in cell counts was observed, instead of the 4-log reduction attributed to pH effects in the buffered solution. Higher concentrations of these acids at the same pH aided in the killing of the E. coli cells, resulting in a 6-log or greater reduction in cell numbers. No protective effect was observed when citric acid was added to the E. coli cells. d-Lactic acid had a greater protective effect than other acids at concentrations of 1 to 20 mM. Less than a 1-log decrease in cell numbers occurred during the 6-h exposure to pH 3.2. To our knowledge, this is the first report of the protective effect of organic acids on the survival of E. coli O15:H7 under low-pH conditions.

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Assessing the Efficacy of Sodium Bisulfate and Organic Acid Treatments for Control of Salmonella Typhimurium in Rendered Chicken Fat Applied to Pet Foods

Journal of Food Protection ◽

10.4315/0362-028x.jfp-18-560 ◽

2019 ◽

Vol 82 (11) ◽

pp. 1864-1869 ◽

Cited By ~ 1

Author(s):

JANAK DHAKAL ◽

CHARLES G. ALDRICH ◽

CARL KNUEVEN

Keyword(s):

Lactic Acid ◽

Synergistic Effect ◽

Organic Acids ◽

Positive Control ◽

Water Phase ◽

Residual Water ◽

Chicken Fat ◽

Log Reduction ◽

Sodium Bisulfate ◽

The Given

ABSTRACT This study was conducted to evaluate the effects of sodium bisulfate (SBS), lactic acid (LA), phosphoric acid (PA), and combinations of organic acids with SBS on Salmonella in rendered chicken fat and in water. The MICs of the antimicrobials individually and in combination were determined. Efficacies of the antimicrobials against Salmonella were tested in both media. The MICs of SBS, LA, and PA were 0.5, 0.5, and 0.25%, respectively. At the given concentrations in the water phase, 0.5% SBS was more effective (P < 0.05; 2.7-log reduction) than LA and PA at 0 h. SBS and LA were more effective (P < 0.05) than PA with >4-log reductions at 2 h and complete kill at 6 h. After 24 h, each of the chemicals completely eliminated the Salmonella. However, because of low recovery in the fat phase, Salmonella was not detected after 12 h and all three chemicals effectively reduced (P < 0.05) Salmonella at 6 h compared with the control. When combinations were used in the water phase, SBS plus butyric acid decreased (P < 0.05) Salmonella by >5.5 log CFU/mL after 12 h. The SBS+LA combinations were effective (P < 0.05) after 2 h. The combinations of SBS+PA resulted in ∼3.5-log reductions in Salmonella (P < 0.05) after 6 h. In the fat phase, except for the SBS+PA combination, Salmonella reduction was not different from that for the positive control. When SBS was combined with organic acids, Salmonella inhibition was achieved at a lower SBS concentration, indicating a possibly synergistic effect of these chemicals. These results suggest that inclusion of SBS or LA at 0.5% individually or a combination of SBS with organic acids could reduce Salmonella in rendered chicken fat contaminated by residual water encountered during storage and transport.

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