Philip G Crandall

University of Arkansas, Fayetteville, Arkansas, United States

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Publications (114)179.8 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Deli meat slicers have been implicated in cross-contamination of ready-to-eat (RTE) foods with Listeria monocytogenes that has resulted in several listeriosis outbreaks. We investigated the lethality of moist heat and silver dihydrogen citrate (SDC) sanitizer on Listeria species that were inoculated on stainless steel (SS) and cast aluminum (AL) coupons cut from actual components of a deli meat slicer. The coupons inoculated with Listeria species were subjected to treatments inside and outside of meat slicer using a commercial bread proofer that was operated for 7 h at 66 °C. Post treatment recoveries of the inoculated Listeria from the treated coupons were enumerated using MOX growth medium. All treatments produced significant (P = 0.05) log reductions compared with positive and untreated negative controls. Moist heat reduced the inoculated bacteria to non-detectable levels when the coupons were placed inside the motor compartment of the slicer and the sanitizer plus moist heat gave same results for the coupons placed inside and outside of the slicer. Chemical sanitizer treatment alone showed average log reductions of around 5 CFU/cm2 on AL and SS coupons respectively and the moist heat alone treatment on both AL and SS coupons showed a log reduction of 4.49 and 4.87 when placed externally and above 6 logs when placed inside the motor compartment. Sanitizer plus moist heat treatments showed highest log reductions of Listeria species to non-detectable levels on deli meat slicer components when placed inside or outside the motor compartment of the slicer. Thus the sanitizer and moist heat combination treatments can effectively reduce the Listeria cells attached onto food contact surfaces of a deli meat slicer.
    Food Control 10/2014; 44:227–232. · 2.74 Impact Factor
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    ABSTRACT: Cross-contamination of pathogens and spoilage bacteria during slicing of ready to eat meats is an important factor that has been shown to impact both food quality and consumers' safety. In this study we analyzed the microbial diversity and total microbiological ecology of different niches on 8 deli meat slicers using standard plate counts as well as culture-independent PCR-denaturing gradient gel electrophoresis (DGGE) analysis. Using aerobic plate counts it was determined that areas underneath the slicer and on the back plate had the highest total bacterial populations. There was slight similarity between total aerobic plate counts by slicer and the number of bacterial genera/species determined by DGGE. The DGGE analysis demonstrated that members of the genus Pseudomonas were the most common bacteria to be found on slicers. This may serve as an estimate of the effectiveness of current cleaning and sanitizing practices to remove biofilms, a possible role for competitive inhibition in preventing colonization by pathogens and an indication of the range and diversity of non-pathogens on these food contact surfaces.
    Food Control 08/2014; 42:242–247. · 2.74 Impact Factor
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    ABSTRACT: Communicating complex scientific and technical information presents a challenge for food science educators. The most efficient learning occurs when all senses are engaged, one reason that many educators believe that scientific principles are best taught with hands-on laboratory experiences. Today there are many challenges to the continuation of these “wet labs” including the cost of building the labs as well as equipment, materials, and personnel to run them. Many current e-learning technologies are based on 2-dimensional delivery systems, and are often inadequate to provide a substitute for a laboratory exercise. However, recent advances in technology have evolved to more closely reflect the kinds of learning experiences that students typically have in a laboratory class. This review describes the role of these emerging technologies as teaching tools for educators, with the clear understanding that similar concepts can be utilized by management of technical teams in the work place.
    Journal of Food Science Education 07/2014; 13(3).
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    ABSTRACT: Condensed smoke or liquid smoke (LS) and lauric arginate (LAE) are antimicrobials used in food preservation. They have demonstrated abilities to reduce or inhibit pathogenic and spoilage organisms. Few studies, however, have reported on the effectiveness of LS or LAE over the range of temperatures typically encountered in food marketing channels. Therefore, the effects of temperature on the antimicrobial properties of two commercial LS fractions, an LS derived from pecan shells, and LAE against two common foodborne pathogens, Listeria and Salmonella, were investigated. The MICs of the three LS samples and LAE were measured at 4, 10, and 37°C for Listeria monocytogenes strains 2045 (Scott A, serotype 4b) and 10403S (serotype 1/2a) and two strains of Listeria innocua, a well-established surrogate, and at 10, 25, and 37°C for Salmonella enterica serovar Typhimurium and Salmonella enterica serovar Heidelberg. The MICs for LS against Listeria ranged from 3 to 48% (vol/vol), with higher MICs seen with lower temperatures. The MICs for LS on Salmonella ranged from 3 to 24%. Values for LAE ranged between 0.004 and 0.07% for both pathogens, and like LS, higher MICs were always associated with lower incubation temperatures. Understanding how storage temperature affects the efficacy of antimicrobials is an important factor that can contribute to lowering the hurdles of use levels and costs of antimicrobials and ultimately improve food safety for the consumer.
    Journal of food protection 06/2014; 77(6):934-40. · 1.83 Impact Factor
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    ABSTRACT: Listeria monocytogenes is an important foodborne pathogen that may be transmitted from the food-processing environment to food; however, the ecology and interaction of this organism with microbial residents on surfaces within the food industry is not well understood. The current study was undertaken to investigate the influence of Listeria innocua on the growth and attachment of L. monocytogenes to stainless steel or aluminum surfaces at 23 °C. When grown in broth as a mixed culture, L. innocua reached a higher cell count at 24 h than did L. monocytogenes. Attachment was evaluated by placing an aliquot containing 103 CFU/ml of L. innocua and 103 CFU/ml of L. monocytogenes on the coupons and by quantifying attached cells after 24 and 72 h. Attachment of L. monocytogenes was decreased by the presence of L. innocua. When compared to L. monocytogenes alone, there was a significant reduction of attachment of L. monocytogenes at 24 and 72 h on stainless steel and 72 h on aluminum surface when L. innocua was added at the same time. L. innocua exhibited an effect on the attachment of L. monocytogenes, increasing our knowledge of the behavior of L. monocytogenes in the presence of another Listeria species.
    Food Control 05/2014; 39:135–138. · 2.74 Impact Factor
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    ABSTRACT: Methionine is the first limiting amino acid in poultry feed. Currently, methionine supplement is synthesized from an expensive chemical process requiring hazardous chemicals. Therefore, the objectives of this study were isolation of methionine producing bacteria from environmental samples and quantification of methionine production in these isolated bacteria. MCGC medium was selected as the isolation medium for methionine-producing bacteria by using Corynebacterium glutamicum ATCC13032 and Escherichia coli ATCC23798 as the positive and negative controls, respectively. Thirty-nine bacterial strains were obtained from environmental samples. Only strains A121, A122, A151 and A181 were able to tolerate up to 0.1% (w/v) of ethionine or norleucine. These isolated strains were identified by sequencing small subunit rRNA genes. The results revealed that bacterial strains A121, A122, A151and A181 were Klebsiella species, Acinetobacter baumannii, A. baumannii and Pseudomonas aeruginosa, respectively. When methionine production in strains A121 and A181 was quantitated, strains A121 and A181 generated methionine up to 31.1 and 124.6 μg/ml, respectively.
    Journal of Environmental Science and Health Part B Pesticides Food Contaminants and Agricultural Wastes 01/2014; 49(4):290-8. · 1.10 Impact Factor
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    ABSTRACT: The smoking of foods, especially meats, has been used as a preservation technique for centuries. Today, smoking methods often involve the use of wood smoke condensates, commonly known as liquid smoke. Liquid smoke is produced by condensing wood smoke created by the pyrolysis of sawdust or wood chips followed by removal of the carcinogenic polyaromatic hydrocarbons. The main products of wood pyrolysis are phenols, carbonyls and organic acids which are responsible for the flavor, color and antimicrobial properties of liquid smoke. Several common food-borne pathogens such as Listeria monocytogenes, Salmonella, pathogenic Escherichia coli and Staphylococcus have shown sensitivity to liquid smoke in vitro and in food systems. Therefore liquid smoke has potential for use as an all-natural antimicrobial in commercial applications where smoke flavor is desired. This review will cover the application and effectiveness of liquid smoke and fractions of liquid smoke as an all-natural food preservative. This review will be valuable for the industrial and research communities in the food science and technology areas.
    Meat Science 01/2014; 97(2):197–206. · 2.75 Impact Factor
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    ABSTRACT: 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.
    Agriculture, Food and Analytical Bacteriology. 01/2014; 4(2):122-142.
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    ABSTRACT: 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.
    Journal of Food Science 11/2013; · 1.78 Impact Factor
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    ABSTRACT: A growing niche in the locally grown food movement is the small-scale production of broiler chickens using the pasture-raised poultry production model. Limited research exists that focuses on Salmonella and Campylobacter contamination in the environment associated with on-farm processing of pasture-raised broilers. The objective of this study was to establish data relative to Salmonella and Campylobacter prevalence and concentration in soil and mortality compost resulting from prior processing waste disposal in the small-scale, on-farm broiler processing environment. Salmonella and Campylobacter concentrations were determined in soil (n = 42), compost (n = 39), and processing wastewater (PWW; n = 46) samples from 4 small broiler farms using a 3-tube most probable number (MPN) method for Salmonella and direct plating method for Campylobacter. Salmonella prevalence and concentration (mean log10 MPN per sample weight or volume) in soil [60%, 0.97 (95% CI: 0.66 to 1.27)], compost [64%, 0.95 (95% CI: 0.66 to 1.24)], and wastewater [48%, 1.29 (95% CI: 0.87 to 1.71)] were not significantly different (P > 0.05). Although Campylobacter prevalence was not significantly different by sample type (64.3, 64.3, and 45.7% in soil, compost, and PWW, respectively), the concentration (mean log10 cfu) of this pathogen was significantly lower (P < 0.05) in wastewater [2.19 (95% CI: 0.36 to 3.03)] samples compared with soil [3.08 (95% CI: 2.23 to 3.94)], and compost [3.83 (95% CI: 2.71 to 4.95)]. These data provide insight into small-scale poultry production waste disposal practices and provides a record of data that may serve as a guide for future improvement of these practices. Further research is needed regarding the small-scale broiler production environment in relation to improving disposal of processing waste for optimum control of human pathogens.
    Poultry Science 11/2013; 92(11):3060-6. · 1.52 Impact Factor
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    ABSTRACT: The small-scale, pasture-raised poultry production model is a growing niche in the locally grown food movement. Research that focuses on the food safety of small-scale broiler processing methods is limited. The objective of this study was to compare Salmonella and Campylobacter prevalence and concentrations on pasture-raised broilers processed on-farm, in a small United States Department of Agriculture – Inspected slaughter facility (USDA-IF), and in a Mobile Processing Unit (MPU) pilot plant. A total of 120, 100, and 50 post-chill, pasture-raised broiler carcasses were sampled from each processing method, respectively. Pathogen prevalence and concentrations from whole carcass rinses were determined using a 3-tube Most Probable Number (MPN) method for Salmonella and direct plating method for Campylobacter according to the USDA-Food Safety and Inspection Service (FSIS) protocols. Both Salmonella prevalence and concentrations on-farm (89% and 1.78 MPN/carcass [95% CI: 1.60–1.96]), USDA-IF (43% and 0.78 MPN/carcass [95% CI: 0.58–0.98]) were significantly (P < 0.05) different. Salmonella was not detected on carcasses processed via the MPU. Campylobacter prevalence was not significantly (P > 0.05) different on carcasses processed by the three methods (70% on-farm, 82% USDA-IF, and 100% MPU). The mean log10Campylobacter concentrations in MPU processed carcasses (5.44 log10 CFU/carcass [95% CI: 5.24–5.63]) was significantly higher (P < 0.05) compared to on-farm (2.32 log10 CFU/carcass [95% CI: 2.06–2.80]) and USDA-IF (2.44 log10 CFU/carcass [95% CI: 2.03–2.85]). Based on the results of this baseline study, most pasture-raised broilers processed by the three methods were contaminated with Salmonella and/or Campylobacter. Further research is needed to assess other potential risk factors such as farm and regional variations that may contribute to the differences in pathogens' prevalence and concentrations.
    Food Control. 11/2013; 34(1):177–182.
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    ABSTRACT: In this study we assessed the use of acridine orange as an alternative to optical density to quantify the growth of Lactobacillus bulgaricus ATCC 7517. The growth of bacteria in Lactobacillus de Man Rogosa Sharpe (MRS) medium was measured by both acridine orange (AO) and optical density (OD) measurements for 24 h. The relationship between both methods was compared via correlation analysis. The doubling time of bacteria based on the values of OD and AO obtained during 24 h growth were also calculated. The result shows strong correlation of cell growth between OD and AO during the first 10 hours of growth, but the correlation was less strong when analyzing the data from 0 to 24 hours. Growth rates, generation time and lag time were also similar. This study indicates that AO could be used in place of OD to prepare growth curves of Lactobacillus bulgaricus during the exponential phase of growth, and to compare growth rates, generation times or lag times.
    Journal of Environmental Science and Health Part B Pesticides Food Contaminants and Agricultural Wastes 06/2013; 48(6):512-5. · 1.10 Impact Factor
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    Journal of Probiotics & Health. 05/2013; 1(2).
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    ABSTRACT: 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.
    Meat Science 04/2013; 95(2):137-144. · 2.75 Impact Factor
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    ABSTRACT: Food-contact surfaces are highly contaminated with microorganism and great sources for transmission of foodborne pathogens. It is important to eliminate bacteria using appropriate sanitizing approaches to minimize cross-contamination during food preparation and/or consumption and reduce the risk of foodborne diseases. The objective of this study was to compare the removal efficiency of bacteria on food-contact surfaces by different cleaning cloths. Commercially available blended cellulose/cotton cloth, microfiber, scouring cloth, nonwoven fabric and terry towel were used. Stainless steel and Formica laminate surfaces were inoculated with Listeria monocytogenes in ready-to-eat turkey slurry and the surface was wiped with different cloths. The remaining bacteria on the food-contact surfaces and bacteria immersed in each cloth were enumerated. Overall significant reductions were observed on stainless steel and Formica laminate surfaces by 0.92–2.62 and 2.21–3.44 log CFU/cm2 reduction, respectively (P < 0.05). Among all cloths, blended cellulose/cotton cloths showed the highest removal efficiency by 2.53–2.62 (stainless steel) and 3.16–3.44 (Formica) log CFU/cm2 reduction. Bacteria captured by each cloth did not show significant differences with the range of 5.40–5.69 log CFU/cm2 (stainless steel) and 2.78–3.62 log CFU/cm2 (Formica). ATP bioluminescence assay result was significantly reduced by cleaning cloths (P < 0.05) while the relative luminescence unit (RLU) value was higher on stainless steel by 2547–6073 RLU than on Formica by 208–503 RLU. These results indicate that the performance of cleaning cloths varied for the removal of bacteria and food debris depending on the fabric material and processing pattern.
    Food Control. 03/2013; 30(1):292–297.
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    Journal of Food Research. 02/2013; 2(1):158-167.
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    ABSTRACT: BACKGROUND: Wheat flour is increasingly being fortified worldwide with vitamin A and iron. Research on high levels of fortification is limited; therefore, in this study, wheat flour was made under controlled conditions fortified with vitamin A at 30 000 or 70 000 retinol equivalents (RE) kg(-1) and three types of iron source at 66 mg kg(-1) . RESULTS: Milling produced a uniform distribution of fortificants with no significant separation during packaging or transportation. Chemical and physical analyses demonstrated that the dual fortified flours had acceptable physicochemical properties of mixing tolerance, pasting curves, damaged starch and falling numbers. The level of vitamin A fortification compensated for initial loss caused during wheat processing. Overall, white breads baked from seven treatments of fortified flour had only 22% (eight out of 36) of the sensory attributes as being significantly different. However, the type of iron source may play a key role in modulating the sensory attributes of bread baked from the dual fortified flour with vitamin A and iron. CONCLUSION: The findings suggest that dual fortified flour with high or even lower levels of vitamin A and iron could be considered for food fortification programmes to reduce the prevalence of micronutrient undernutrition of vitamin A and iron in developing countries. © 2013 Society of Chemical Industry.
    Journal of the Science of Food and Agriculture 01/2013; · 1.88 Impact Factor
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    ABSTRACT: Control of Listeria monocytogenes in ready-to-eat (RTE) food products is a significant challenge and improved means for control are needed. In this study, the anti-listerial effects of three lactic acid bacteria (LAB) were investigated. Spot-on-lawn assays demonstrated the largest zones of inhibition against L. monocytogenes were produced by the Pediococcus acidilactici strain, with zone diameters ranging from 13 to 18 mm. Minimum inhibitory concentration (MIC) experiments using cell free supernatant (CFS) from the LAB revealed that while two of the strains were effective at inhibiting L. monocytogenes growth only up to a 1:4 dilution, P. acidilactici was able to inhibit growth up to a 1:256 dilution. Survival assays performed at 7°C determined that the P. acidilactici strain was capable of producing a 4.5 log reduction in L. monocytogenes counts and maintaining the reduction for 21 days. The effectiveness of P. acidilactici was reduced under log phase growth, autoclaving for longer than 15 min (121°C and 15 psi), and treatment with proteinase K (25 mg/mL).
    Journal of Environmental Science and Health Part B Pesticides Food Contaminants and Agricultural Wastes 01/2013; 48(1):63-8. · 1.10 Impact Factor
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    ABSTRACT: An online questionnaire was developed that targeted consumers with an interest in sustainable and local poultry production in Georgia. Approximately 97% of the respondents expressed an interest in supporting efforts to make sustainably raised poultry processed in Georgia available. Even for a high premium of $5.00/lb, some respondents would shift their current chicken purchases towards these locally raised chickens. Respondents reported some interest in attributes such as pasture raised, air chilled and Georgia grown for their poultry. Knowledge about the demand for local pastured poultry supports the need for infrastructure to support Mobile Processing Units for Georgia farmers interested in locally raised small-scale poultry production.
    Agriculture, Food and Analytical Bacteriology. 01/2013; 3:94-102.
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    ABSTRACT: Ingestion of ready-to-eat deli meats contaminated with foodborne pathogens has been linked to several outbreaks. For this study, a fluorescent compound (FC) was used to observe deli workers in cross-contamination events to visualize and quantify how potential microbial contamination can move within a mock retail deli environment. Twenty-one participants were recruited and were asked to complete a series of steps involving the slicing of deli meats in which one of the meat products was inoculated with the FC. Upon completion, 16 separate areas (5 × 5 cm) per participant were swabbed to quantify the amount of FC present. A standard curve for the FC (based on absorbance at 370 nm) was developed in order to quantify the amount of FC. For each participant, both video and image data were also collected. These data were normalized and reported as percentages of the total amount of FC collected per participant to allow the amount of FC in each area to be compared across participants. Concentrations of FC by area swabbed and participant were highly variable; even so, consistently elevated levels of FC were found on participants' gloves (18%), on the slicer's meat grip (16%), the outside wall of the carriage tray (16%) and within the collection area (13%). Video analysis revealed that high-touch areas include the deli meat, deli meat wrapper, deli paper, and plastic bags which comprised 74% (87 of 118 touches) of the total average hand contact frequency per participant. The relationship between frequency of hand contact and % FC on a particular area swabbed was analyzed, and a Pearson's r value of 0.37 was determined indicating a medium-strength, positive correlation. The findings in this study demonstrate that there is variability among participants within a mock retail deli environment, and thus, likely to be similar variability among workers in an actual retail deli environment. In addition, even in the presence of this variability, this study identifies both areas of elevated contamination levels as well as areas of high hand contact within a deli environment. To our knowledge, this is the first study to quantify cross-contamination events using a FC and to identify potential areas of concern with respect to cleaning and sanitizing as well as employee training.
    Food Control 01/2013; 31:116-124. · 2.74 Impact Factor

Publication Stats

348 Citations
179.80 Total Impact Points


  • 2010–2014
    • University of Arkansas
      • Department of Food Science
      Fayetteville, Arkansas, United States
    • Texas A&M University
      • Department of Poultry Science
      College Station, TX, United States
  • 2012
    • University of Novi Sad
      • Department of Animal Science
      Novi Sad, VO, Serbia
    • Purdue University
      • Department of Animal Sciences
      West Lafayette, IN, United States
  • 2011–2012
    • Colorado State University
      • Department of Animal Sciences
      Fort Collins, Colorado, United States
    • Chinese Academy of Agricultural Sciences
      Peping, Beijing, China
  • 2009
    • Abraham Baldwin Agricultural College
      College Station, Texas, United States
  • 1988–2007
    • University of Florida
      • Citrus Research and Education Center
      Gainesville, FL, United States
  • 2006
    • Oklahoma State University - Oklahoma City
      Oklahoma City, Oklahoma, United States