The Oklahoma Cooperative Extension Service periodically issues revisions to its publications. The... more The Oklahoma Cooperative Extension Service periodically issues revisions to its publications. The most current edition is made available. For access to an earlier edition, if available for this title, please contact the Oklahoma State University Library Archives by email at [email protected] or by phone at 405-744-6311
Several organic acid based antimicrobials are reported to reduce bacterial populations but studie... more Several organic acid based antimicrobials are reported to reduce bacterial populations but studies showing inhibition of autoinducer-2 (AI-2) activity or quorum sensing are limited. The effect of lactic and malic acids on autoinducer activity of selected strains of E. coli O157:H7 and Salmonella Typhimurium is tested in this study. The strains were screened for AI-2 like activity on spinach and cantaloupe homogenates using autoinducer sensing V. harveyi biosensor strains. The ED 14 strain of E. coli O157:H7 and the SD 10 strain of Salmonella showed highest AI-2 like activity of 55 and 53 Relative Light Units respectively. These two strains were used to evaluate the AI-2 inhibitory activities of lactic and malic acids at 1 to 4% concentrations (alone or in combinations). Lactic acid at 4.0% had the highest inhibition of 80% on ED 14 E. coli strain while the combination treatment of lactic acid + malic acid at 4.0% each had the highest inhibition of 80% on SD 10 Salmonella strain. Results from the study indicate that the quorum sensing ability of the E. coli O157:H7 and Salmonella Typhimurium strains can be effectively inhibited by antimicrobial organic acids.
Aflatoxins are considered unavoidable natural mycotoxins encountered in foods, animal feeds, and ... more Aflatoxins are considered unavoidable natural mycotoxins encountered in foods, animal feeds, and feed grains. In this study, we demonstrate the application of our recently developed real-time immunoquantitative PCR (RT iq-PCR) assay for sensitive detection and quantification of aflatoxins in poultry feed, two types of dairy feed (1 and 2), horse feed, whole kernel corn feed grains, and retail yellow ground corn meal. Upon testing methanol/water (60:40) extractions of the above samples using competitive direct enzyme linked immunosorbent assay, the aflatoxin content was found to be <20 μg/kg. The RT iq-PCR assay exhibited high antigen hook effect in samples containing aflatoxin levels higher than the quantification limits (0.1-10 μg/kg), addressed by comparing the quantification results of undiluted and diluted extracts. In testing the reliability of the immuno-PCR assay, samples were spiked with 200 μg/kg of aflatoxin B1, but the recovery of spiked aflatoxin was found to be poor. Considering the significance of determining trace levels of aflatoxins and their serious implications for animal and human health, the RT iq-PCR method described in this study can be useful for quantifying low natural aflatoxin levels in
Liquid smoke extracts have traditionally been used as flavoring agents, are known to possess anti... more Liquid smoke extracts have traditionally been used as flavoring agents, are known to possess antioxidant properties, and serve as natural alternatives to conventional antimicrobials. The antimicrobial efficacies of commercial liquid smoke samples may vary depending on their source and composition and the methods used to extract and concentrate the smoke. We investigated the MICs of eight commercial liquid smoke samples against Salmonella Enteritidis, Staphylococcus aureus, and Escherichia coli. The commercial liquid smoke samples purchased were supplied by the manufacturer as water-based or concentrated extracts of smoke from different wood sources. The MICs of the commercial smokes to inhibit the growth of foodborne pathogens ranged from 0.5 to 6.0% for E. coli, 0.5 to 8.0% for Salmonella, and 0.38 to 6% for S. aureus. The MIC for each liquid smoke sample was similar in its effect on both E. coli and Salmonella. Solvent-extracted antimicrobials prepared using pecan shells displayed...
Antimicrobial compounds of plant origin are used as natural preservatives to control spoilage and... more Antimicrobial compounds of plant origin are used as natural preservatives to control spoilage and pathogenic bacteria in foods. The food safety applications of these plant derived compounds are considered as natural alternatives to chemical antimicrobial agents, in addition to being cheaper and safer substitutes. These bioactive compounds in plants are secondary metabolites, usually produced and accumulated in various plant parts and their activities depend on the concentration, composition, structure, and functional groups. Major examples of such plant compounds include vitamins, antioxidants, essential oils, hydrocolloids, proteins, aldehydes, flavonoids, and other phytochemicals. These compounds have been documented to exhibit antimicrobial properties against various foodborne pathogens. The food safety applications of selected plant derived antimicrobials in controlling survival and resistance of pathogens in foods are briefly discussed in this chapter.
Isoflavones are a group of chemicals that are found in legumes, predominantly in soybean and soy ... more Isoflavones are a group of chemicals that are found in legumes, predominantly in soybean and soy products. Soy isoflavones have been a component of the diet of certain populations for centuries. Many health claims have been made for isoflavones including: cancer prevention, alleviation of menopausal symptoms, positive effects on bone health and a lowering of blood lipids leading to lowered susceptibility to cardiovascular disease. However, because of their estrogenic activity ome negative effects of isoflavones have been postulated. This review examines the literature associated with benefits as well as the negative effects of consumption of soy isoflavones. Results in some studies are limited or conflicting, but when viewed in its entirety, the current literature supports the safety of isoflavones as typically consumed in diets based on soy containing products.
This study investigated the inhibition of yeasts in brines from fermented cucumber pickles using ... more This study investigated the inhibition of yeasts in brines from fermented cucumber pickles using 2, 4-hexadienoic (sorbic), hexanoic and (E)-3-hexenoic acids. Native yeast population and chemical composition of commercial brines were analyzed and the minimum inhibitory concentrations of inhibitors on yeast growth were established. Commercial brines were treated with 100-350 ppm of 2, 4-hexadienoic (sorbic), hexanoic and (E)-3-hexenoic acids individually and at 2.5 to 10% salt (sodium chloride) concentrations. Yeast populations in the treated brines were monitored for 30 days of incubation. Hexanoic and (E)-3-hexenoic acids at 350 ppm caused reduction in yeast populations by about 4 and 2 log CFU/ml, respectively, within 24 hours of treatment. However, when brines were treated with 2, 4-hexadienoic acid at salt concentrations of 7.5 to 10%, there were no significant differences noted in yeast inhibition between the three acids. Hexanoic and (E)-3-hexenoic acids at 200 ppm caused longer lasting inhibitory effects (30 days) on yeasts than the traditionally used 2, 4-hexadienoic acid (10 days) in fermentation brine. Thus, the hexanoic and (E)-3-hexenoic acids are potential alternatives to 2, 4-hexadienoic acid for controlling yeasts during storage of spent cucumber fermentation brines.
The viable-but-nonculturable (VBNC) state among certain microorganisms is believed to be a surviv... more The viable-but-nonculturable (VBNC) state among certain microorganisms is believed to be a survival mechanism under stress conditions as they lose their ability to grow and multiply. The molecular mechanism of the nonculturable cells is perplexing and the VBNC condition is controversial. There is a growing academic interest to study the VBNC cells that are not easily detectable by the existing methods and to understand the implications of VBNC cells for public health. Further studies on the molecular understanding of these cells are needed to definitively understand the VBNC mechanism in different microorganisms.
Traceability through the entire food supply chain from conception to consumption is a pressing ne... more Traceability through the entire food supply chain from conception to consumption is a pressing need for the food industry, consumers and government regulators. A robust, whole-chain traceability system is needed that will effectively address food quality, food safety and food defense issues by providing real-time, transparent and reliable information from beef production through slaughter and distribution to the consumer. Traceability is an expanding part of the food safety continuum that minimizes the risk of foodborne diseases, assures quality and cold-chain integrity. Traceability can be a positive competitive marketing edge for beef producers who can verify specific quality attributes such as humane production or grass fed or Certified Organic. In this review we address the benefits as well as the remaining issues for whole-chain traceability in the beef industry, with particular focus on ground beef for the markets in the United States.
Whole mango peel powder and fibre extracted from mango peel were investigated as potential ingred... more Whole mango peel powder and fibre extracted from mango peel were investigated as potential ingredients to replace salt and phosphate in chicken marinade. Whole mango peel powder possessed higher water absorption capacity than mango peel fibre, 4.57% and 1.47%, respectively (P < 0.05). Similar oil absorption capacity was observed in both mango peel ingredients (P > 0.05). Purified pectin and sorbitol syrup were also used to compare the water holding capacity in marinated chicken breasts. Mango peel ingredients exhibited less cooking loss than pectin and sorbitol syrup, however, higher cooking loss than sodium tripolyphosphate (STPP) and NaCl (P > 0.05). Marinating with mango peel ingredients significantly increased a* value of chicken breasts after cooking, while L* and b* values were similar in marinating with NaCl (P > 0.05). Hardness of frozen fully cooked chicken breast was measured after thawing. The lowest shear force of 7.13 N was observed in chicken breasts marinated with mango peel fibre (P < 0.05), while the hardness of chicken breasts marinated with whole mango peel powder was not significant different from STPP and NaCl treatments. Results from this study revealed a potential approach of utilizing fruit waste as an ingredient to substitute for phosphate and salt in chicken marinade.
Growers and processors of USDA certified organic foods are in need of suitable organic antimicrob... more Growers and processors of USDA certified organic foods are in need of suitable organic antimicrobials. The purpose of the research reported here was to develop and test natural antimicrobials derived from an all-natural by-product, organic pecan shells. Unroasted and roasted organic pecan shells were subjected to solvent free extraction to produce antimicrobials that were tested against Listeria spp. and L. monocytogenes serotypes to determine the minimum inhibitory concentrations (MIC) of antimicrobials. The effectiveness of pecan shell extracts were further tested using a poultry skin model system and the growth inhibition of the Listeria cells adhered onto the skin model were quantified. The solvent free extracts of pecan shells inhibited Listeria strains at MICs as low as 0.38%. The antimicrobial effectiveness tests on a poultry skin model exhibited nearly a 2 log reduction of the inoculated cocktail mix of Listeria strains when extracts of pecan shell powder were used. The extracts also produced greater than a 4 log reduction of the indigenous spoilage bacteria on the chicken skin. Thus, the pecan shell extracts may prove to be very effective alternative antimicrobials against food pathogens and supplement the demand for effective natural antimicrobials for use in organic meat processing.
This study investigated the inhibition of yeasts in brines from fermented cucumber pickles using ... more This study investigated the inhibition of yeasts in brines from fermented cucumber pickles using 2, 4-hexadienoic (sorbic), hexanoic and (E)-3-hexenoic acids. Native yeast population and chemical composition of commercial brines were analyzed and the minimum inhibitory concentrations of inhibitors on yeast growth were established. Commercial brines were treated with 100-350 ppm of 2, 4-hexadienoic (sorbic), hexanoic and (E)-3-hexenoic acids individually and at 2.5 to 10% salt (sodium chloride) concentrations. Yeast populations in the treated brines were monitored for 30 days of incubation. Hexanoic and (E)-3-hexenoic acids at 350 ppm caused reduction in yeast populations by about 4 and 2 log CFU/ml, respectively, within 24 hours of treatment. However, when brines were treated with 2, 4-hexadienoic acid at salt concentrations of 7.5 to 10%, there were no significant differences noted in yeast inhibition between the three acids. Hexanoic and (E)-3-hexenoic acids at 200 ppm caused longer lasting inhibitory effects (30 days) on yeasts than the traditionally used 2, 4-hexadienoic acid (10 days) in fermentation brine. Thus, the hexanoic and (E)-3-hexenoic acids are potential alternatives to 2, 4-hexadienoic acid for controlling yeasts during storage of spent cucumber fermentation brines.
Aims: To test the efficacy of four wipe cloth types (cotton bar towel, nonwoven, microfibre and b... more Aims: To test the efficacy of four wipe cloth types (cotton bar towel, nonwoven, microfibre and blended cellulose ⁄ cotton) with either quaternary ammonia cleaning solution or silver dihydrogen citrate (SDC) in cleaning food contact surfaces. Methods: Swab samples collected from untreated, cloth-treated and cloth disinfectant-treated surfaces were subjected to hygiene monitoring using adenosine triphosphate (ATP) bioluminescence and aerobic total plate counting (TPC) assays. Results: Adenosine triphosphate measurements taken after wiping the surfaces showed poor cleaning by nonwoven cloths (2AE89 RLU 100 cm)2) than the microfibre (2AE30 RLU 100 cm)2), cotton terry bar (2AE26 RLU 100 cm)2) and blended cellulose ⁄ cotton cloth types (2AE20 RLU 100 cm)2). The cellulose ⁄ cotton cloth showed highest log reduction in ATP-B RLU values (95%) and CFU values (98AE03%) when used in combination with SDC disinfectant. Conclusions: Cleaning effect of wiping cloths on food contact surfaces can be enhanced by dipping them in SDC disinfectant. ATP-B measurements can be used for real-time hygiene monitoring in public sector, and testing microbial contamination provides more reliable measure of cleanliness. Significance and Impact of the Study: Contaminated food contact surfaces need regular hygiene monitoring. This study could help to estimate and establish contamination thresholds for surfaces at public sector facilities and to base the effectiveness of cleaning methods.
Soybean seed coats are an underutilized byproduct from the commercial crushing of soybeans to mak... more Soybean seed coats are an underutilized byproduct from the commercial crushing of soybeans to make soymeal and soy oil. These seed coats constitute 7 to 10% of the weight of a bushel of soybeans so they provide a substantial opportunity to add value to each bushel. Overall, the United States produces approximately 6 million metric tons of seed coats each year. Biologically active compounds contained in soybean seed coats have been shown to prevent and or reduce macular degeneration, obesity, cancer, and many other debilitating diseases. For example the seed coats of YJ-100 black soybeans contain more than 20 mg/g of anthocyanins, the highest concentration of anthocyanins of all plants materials including other row crops. The purpose of this paper is to examine the chemical content of soybean seed coats, highlight opportunities to add value and discuss the potential health benefits of these chemicals.
Aflatoxin B 1 is an unavoidable natural mycotoxin that enters the food chain by contamination of ... more Aflatoxin B 1 is an unavoidable natural mycotoxin that enters the food chain by contamination of food grains and feedstuffs, potentially posing carcinogenic risks to animal and human health. Immuno-PCR methods have the potential to address the need of meeting the regulatory limits by detecting trace levels of toxins present in food and animal feeds. This paper describes a real-time immuno-quantitative PCR (RT-iqPCR) assay for quantification of aflatoxin B 1 suspended in methanol:water solution that can also serve as an extraction solvent. Immuno-PCR approaches were examined including direct vs. indirect sandwich assays using monoclonal vs. polyclonal antibodies. Our best approach was obtained using monoclonal antibodies to capture aflatoxin in solution prior to immobilizing the F c portion of the capture antibodies onto to protein G magnetic beads. This was followed by the addition of a polyclonal 'signal antibody' tethered with an oligonucleotide template for a subsequent PCR assay. The RT-iqPCR assay described herein leads to the sensitive detection and quantification of aflatoxin B 1 from 10 ppb down to 0.1 ppb with high correlation (r 2 = 0.97) and efficiency (99.5%). The approach also detected the high-dose 'hook effect' phenomenon (excess antigen) which was overcome by the use of dilution protocols to eliminate false negatives that may occur at levels above quantification limits of the assay. The RT-iqPCR approach discussed here is presented as a model system that could easily be adapted for aflatoxin detection in a variety of food or animal feed samples using a simple methanol:water solution as an extraction solvent.
The Oklahoma Cooperative Extension Service periodically issues revisions to its publications. The... more The Oklahoma Cooperative Extension Service periodically issues revisions to its publications. The most current edition is made available. For access to an earlier edition, if available for this title, please contact the Oklahoma State University Library Archives by email at [email protected] or by phone at 405-744-6311
Several organic acid based antimicrobials are reported to reduce bacterial populations but studie... more Several organic acid based antimicrobials are reported to reduce bacterial populations but studies showing inhibition of autoinducer-2 (AI-2) activity or quorum sensing are limited. The effect of lactic and malic acids on autoinducer activity of selected strains of E. coli O157:H7 and Salmonella Typhimurium is tested in this study. The strains were screened for AI-2 like activity on spinach and cantaloupe homogenates using autoinducer sensing V. harveyi biosensor strains. The ED 14 strain of E. coli O157:H7 and the SD 10 strain of Salmonella showed highest AI-2 like activity of 55 and 53 Relative Light Units respectively. These two strains were used to evaluate the AI-2 inhibitory activities of lactic and malic acids at 1 to 4% concentrations (alone or in combinations). Lactic acid at 4.0% had the highest inhibition of 80% on ED 14 E. coli strain while the combination treatment of lactic acid + malic acid at 4.0% each had the highest inhibition of 80% on SD 10 Salmonella strain. Results from the study indicate that the quorum sensing ability of the E. coli O157:H7 and Salmonella Typhimurium strains can be effectively inhibited by antimicrobial organic acids.
Aflatoxins are considered unavoidable natural mycotoxins encountered in foods, animal feeds, and ... more Aflatoxins are considered unavoidable natural mycotoxins encountered in foods, animal feeds, and feed grains. In this study, we demonstrate the application of our recently developed real-time immunoquantitative PCR (RT iq-PCR) assay for sensitive detection and quantification of aflatoxins in poultry feed, two types of dairy feed (1 and 2), horse feed, whole kernel corn feed grains, and retail yellow ground corn meal. Upon testing methanol/water (60:40) extractions of the above samples using competitive direct enzyme linked immunosorbent assay, the aflatoxin content was found to be <20 μg/kg. The RT iq-PCR assay exhibited high antigen hook effect in samples containing aflatoxin levels higher than the quantification limits (0.1-10 μg/kg), addressed by comparing the quantification results of undiluted and diluted extracts. In testing the reliability of the immuno-PCR assay, samples were spiked with 200 μg/kg of aflatoxin B1, but the recovery of spiked aflatoxin was found to be poor. Considering the significance of determining trace levels of aflatoxins and their serious implications for animal and human health, the RT iq-PCR method described in this study can be useful for quantifying low natural aflatoxin levels in
Liquid smoke extracts have traditionally been used as flavoring agents, are known to possess anti... more Liquid smoke extracts have traditionally been used as flavoring agents, are known to possess antioxidant properties, and serve as natural alternatives to conventional antimicrobials. The antimicrobial efficacies of commercial liquid smoke samples may vary depending on their source and composition and the methods used to extract and concentrate the smoke. We investigated the MICs of eight commercial liquid smoke samples against Salmonella Enteritidis, Staphylococcus aureus, and Escherichia coli. The commercial liquid smoke samples purchased were supplied by the manufacturer as water-based or concentrated extracts of smoke from different wood sources. The MICs of the commercial smokes to inhibit the growth of foodborne pathogens ranged from 0.5 to 6.0% for E. coli, 0.5 to 8.0% for Salmonella, and 0.38 to 6% for S. aureus. The MIC for each liquid smoke sample was similar in its effect on both E. coli and Salmonella. Solvent-extracted antimicrobials prepared using pecan shells displayed...
Antimicrobial compounds of plant origin are used as natural preservatives to control spoilage and... more Antimicrobial compounds of plant origin are used as natural preservatives to control spoilage and pathogenic bacteria in foods. The food safety applications of these plant derived compounds are considered as natural alternatives to chemical antimicrobial agents, in addition to being cheaper and safer substitutes. These bioactive compounds in plants are secondary metabolites, usually produced and accumulated in various plant parts and their activities depend on the concentration, composition, structure, and functional groups. Major examples of such plant compounds include vitamins, antioxidants, essential oils, hydrocolloids, proteins, aldehydes, flavonoids, and other phytochemicals. These compounds have been documented to exhibit antimicrobial properties against various foodborne pathogens. The food safety applications of selected plant derived antimicrobials in controlling survival and resistance of pathogens in foods are briefly discussed in this chapter.
Isoflavones are a group of chemicals that are found in legumes, predominantly in soybean and soy ... more Isoflavones are a group of chemicals that are found in legumes, predominantly in soybean and soy products. Soy isoflavones have been a component of the diet of certain populations for centuries. Many health claims have been made for isoflavones including: cancer prevention, alleviation of menopausal symptoms, positive effects on bone health and a lowering of blood lipids leading to lowered susceptibility to cardiovascular disease. However, because of their estrogenic activity ome negative effects of isoflavones have been postulated. This review examines the literature associated with benefits as well as the negative effects of consumption of soy isoflavones. Results in some studies are limited or conflicting, but when viewed in its entirety, the current literature supports the safety of isoflavones as typically consumed in diets based on soy containing products.
This study investigated the inhibition of yeasts in brines from fermented cucumber pickles using ... more This study investigated the inhibition of yeasts in brines from fermented cucumber pickles using 2, 4-hexadienoic (sorbic), hexanoic and (E)-3-hexenoic acids. Native yeast population and chemical composition of commercial brines were analyzed and the minimum inhibitory concentrations of inhibitors on yeast growth were established. Commercial brines were treated with 100-350 ppm of 2, 4-hexadienoic (sorbic), hexanoic and (E)-3-hexenoic acids individually and at 2.5 to 10% salt (sodium chloride) concentrations. Yeast populations in the treated brines were monitored for 30 days of incubation. Hexanoic and (E)-3-hexenoic acids at 350 ppm caused reduction in yeast populations by about 4 and 2 log CFU/ml, respectively, within 24 hours of treatment. However, when brines were treated with 2, 4-hexadienoic acid at salt concentrations of 7.5 to 10%, there were no significant differences noted in yeast inhibition between the three acids. Hexanoic and (E)-3-hexenoic acids at 200 ppm caused longer lasting inhibitory effects (30 days) on yeasts than the traditionally used 2, 4-hexadienoic acid (10 days) in fermentation brine. Thus, the hexanoic and (E)-3-hexenoic acids are potential alternatives to 2, 4-hexadienoic acid for controlling yeasts during storage of spent cucumber fermentation brines.
The viable-but-nonculturable (VBNC) state among certain microorganisms is believed to be a surviv... more The viable-but-nonculturable (VBNC) state among certain microorganisms is believed to be a survival mechanism under stress conditions as they lose their ability to grow and multiply. The molecular mechanism of the nonculturable cells is perplexing and the VBNC condition is controversial. There is a growing academic interest to study the VBNC cells that are not easily detectable by the existing methods and to understand the implications of VBNC cells for public health. Further studies on the molecular understanding of these cells are needed to definitively understand the VBNC mechanism in different microorganisms.
Traceability through the entire food supply chain from conception to consumption is a pressing ne... more Traceability through the entire food supply chain from conception to consumption is a pressing need for the food industry, consumers and government regulators. A robust, whole-chain traceability system is needed that will effectively address food quality, food safety and food defense issues by providing real-time, transparent and reliable information from beef production through slaughter and distribution to the consumer. Traceability is an expanding part of the food safety continuum that minimizes the risk of foodborne diseases, assures quality and cold-chain integrity. Traceability can be a positive competitive marketing edge for beef producers who can verify specific quality attributes such as humane production or grass fed or Certified Organic. In this review we address the benefits as well as the remaining issues for whole-chain traceability in the beef industry, with particular focus on ground beef for the markets in the United States.
Whole mango peel powder and fibre extracted from mango peel were investigated as potential ingred... more Whole mango peel powder and fibre extracted from mango peel were investigated as potential ingredients to replace salt and phosphate in chicken marinade. Whole mango peel powder possessed higher water absorption capacity than mango peel fibre, 4.57% and 1.47%, respectively (P < 0.05). Similar oil absorption capacity was observed in both mango peel ingredients (P > 0.05). Purified pectin and sorbitol syrup were also used to compare the water holding capacity in marinated chicken breasts. Mango peel ingredients exhibited less cooking loss than pectin and sorbitol syrup, however, higher cooking loss than sodium tripolyphosphate (STPP) and NaCl (P > 0.05). Marinating with mango peel ingredients significantly increased a* value of chicken breasts after cooking, while L* and b* values were similar in marinating with NaCl (P > 0.05). Hardness of frozen fully cooked chicken breast was measured after thawing. The lowest shear force of 7.13 N was observed in chicken breasts marinated with mango peel fibre (P < 0.05), while the hardness of chicken breasts marinated with whole mango peel powder was not significant different from STPP and NaCl treatments. Results from this study revealed a potential approach of utilizing fruit waste as an ingredient to substitute for phosphate and salt in chicken marinade.
Growers and processors of USDA certified organic foods are in need of suitable organic antimicrob... more Growers and processors of USDA certified organic foods are in need of suitable organic antimicrobials. The purpose of the research reported here was to develop and test natural antimicrobials derived from an all-natural by-product, organic pecan shells. Unroasted and roasted organic pecan shells were subjected to solvent free extraction to produce antimicrobials that were tested against Listeria spp. and L. monocytogenes serotypes to determine the minimum inhibitory concentrations (MIC) of antimicrobials. The effectiveness of pecan shell extracts were further tested using a poultry skin model system and the growth inhibition of the Listeria cells adhered onto the skin model were quantified. The solvent free extracts of pecan shells inhibited Listeria strains at MICs as low as 0.38%. The antimicrobial effectiveness tests on a poultry skin model exhibited nearly a 2 log reduction of the inoculated cocktail mix of Listeria strains when extracts of pecan shell powder were used. The extracts also produced greater than a 4 log reduction of the indigenous spoilage bacteria on the chicken skin. Thus, the pecan shell extracts may prove to be very effective alternative antimicrobials against food pathogens and supplement the demand for effective natural antimicrobials for use in organic meat processing.
This study investigated the inhibition of yeasts in brines from fermented cucumber pickles using ... more This study investigated the inhibition of yeasts in brines from fermented cucumber pickles using 2, 4-hexadienoic (sorbic), hexanoic and (E)-3-hexenoic acids. Native yeast population and chemical composition of commercial brines were analyzed and the minimum inhibitory concentrations of inhibitors on yeast growth were established. Commercial brines were treated with 100-350 ppm of 2, 4-hexadienoic (sorbic), hexanoic and (E)-3-hexenoic acids individually and at 2.5 to 10% salt (sodium chloride) concentrations. Yeast populations in the treated brines were monitored for 30 days of incubation. Hexanoic and (E)-3-hexenoic acids at 350 ppm caused reduction in yeast populations by about 4 and 2 log CFU/ml, respectively, within 24 hours of treatment. However, when brines were treated with 2, 4-hexadienoic acid at salt concentrations of 7.5 to 10%, there were no significant differences noted in yeast inhibition between the three acids. Hexanoic and (E)-3-hexenoic acids at 200 ppm caused longer lasting inhibitory effects (30 days) on yeasts than the traditionally used 2, 4-hexadienoic acid (10 days) in fermentation brine. Thus, the hexanoic and (E)-3-hexenoic acids are potential alternatives to 2, 4-hexadienoic acid for controlling yeasts during storage of spent cucumber fermentation brines.
Aims: To test the efficacy of four wipe cloth types (cotton bar towel, nonwoven, microfibre and b... more Aims: To test the efficacy of four wipe cloth types (cotton bar towel, nonwoven, microfibre and blended cellulose ⁄ cotton) with either quaternary ammonia cleaning solution or silver dihydrogen citrate (SDC) in cleaning food contact surfaces. Methods: Swab samples collected from untreated, cloth-treated and cloth disinfectant-treated surfaces were subjected to hygiene monitoring using adenosine triphosphate (ATP) bioluminescence and aerobic total plate counting (TPC) assays. Results: Adenosine triphosphate measurements taken after wiping the surfaces showed poor cleaning by nonwoven cloths (2AE89 RLU 100 cm)2) than the microfibre (2AE30 RLU 100 cm)2), cotton terry bar (2AE26 RLU 100 cm)2) and blended cellulose ⁄ cotton cloth types (2AE20 RLU 100 cm)2). The cellulose ⁄ cotton cloth showed highest log reduction in ATP-B RLU values (95%) and CFU values (98AE03%) when used in combination with SDC disinfectant. Conclusions: Cleaning effect of wiping cloths on food contact surfaces can be enhanced by dipping them in SDC disinfectant. ATP-B measurements can be used for real-time hygiene monitoring in public sector, and testing microbial contamination provides more reliable measure of cleanliness. Significance and Impact of the Study: Contaminated food contact surfaces need regular hygiene monitoring. This study could help to estimate and establish contamination thresholds for surfaces at public sector facilities and to base the effectiveness of cleaning methods.
Soybean seed coats are an underutilized byproduct from the commercial crushing of soybeans to mak... more Soybean seed coats are an underutilized byproduct from the commercial crushing of soybeans to make soymeal and soy oil. These seed coats constitute 7 to 10% of the weight of a bushel of soybeans so they provide a substantial opportunity to add value to each bushel. Overall, the United States produces approximately 6 million metric tons of seed coats each year. Biologically active compounds contained in soybean seed coats have been shown to prevent and or reduce macular degeneration, obesity, cancer, and many other debilitating diseases. For example the seed coats of YJ-100 black soybeans contain more than 20 mg/g of anthocyanins, the highest concentration of anthocyanins of all plants materials including other row crops. The purpose of this paper is to examine the chemical content of soybean seed coats, highlight opportunities to add value and discuss the potential health benefits of these chemicals.
Aflatoxin B 1 is an unavoidable natural mycotoxin that enters the food chain by contamination of ... more Aflatoxin B 1 is an unavoidable natural mycotoxin that enters the food chain by contamination of food grains and feedstuffs, potentially posing carcinogenic risks to animal and human health. Immuno-PCR methods have the potential to address the need of meeting the regulatory limits by detecting trace levels of toxins present in food and animal feeds. This paper describes a real-time immuno-quantitative PCR (RT-iqPCR) assay for quantification of aflatoxin B 1 suspended in methanol:water solution that can also serve as an extraction solvent. Immuno-PCR approaches were examined including direct vs. indirect sandwich assays using monoclonal vs. polyclonal antibodies. Our best approach was obtained using monoclonal antibodies to capture aflatoxin in solution prior to immobilizing the F c portion of the capture antibodies onto to protein G magnetic beads. This was followed by the addition of a polyclonal 'signal antibody' tethered with an oligonucleotide template for a subsequent PCR assay. The RT-iqPCR assay described herein leads to the sensitive detection and quantification of aflatoxin B 1 from 10 ppb down to 0.1 ppb with high correlation (r 2 = 0.97) and efficiency (99.5%). The approach also detected the high-dose 'hook effect' phenomenon (excess antigen) which was overcome by the use of dilution protocols to eliminate false negatives that may occur at levels above quantification limits of the assay. The RT-iqPCR approach discussed here is presented as a model system that could easily be adapted for aflatoxin detection in a variety of food or animal feed samples using a simple methanol:water solution as an extraction solvent.
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