Life Sciences Commons^™

Microbiological Safety And Quality Of Ceviche, Poke, And Sushi Dishes Sold At Retail Outlets In Orange County, Ca, Grace E. Marquis, Samantha M. Covaia, Amanda M. Tabb, Courtney J. Kitch, Rosalee S. Hellberg

Food Science Faculty Articles and Research

Raw, ready-to-eat (RTE) seafood products, such as ceviche, poke, and sushi, have experienced growing demand globally; however, these products have the potential to be contaminated with foodborne pathogens. The objective of this study was to determine the prevalence of Escherichiacoli/coliforms, Salmonella, and Listeria in ceviche, poke, and sushi dishes sold at the retail level in Orange County, CA, USA. Additional organisms detected during testing were also considered in the results. A total of 105 raw, RTE samples of ceviche, poke, and sushi were collected from restaurants and grocery stores in Orange County, CA. Samples were tested for Salmonella …

Effectiveness Of Selected Pre-Enrichment Broths For The Detection Of Salmonella Spp. In Meat Analogs, Georgia L. Sampson, Shannon B. Ruelle, Lieuchi Phan, Donna Williams-Hill, Rosalee S. Hellberg

Food Science Faculty Articles and Research

With the increasing variety of meat analog products, it is important to verify that the methods used for Salmonella detection are effective. The objective of this study was to compare the efficacy of three pre-enrichment broths for the detection of Salmonella in meat analog burgers: the currently used Bacteriological Analytical Manual (BAM) broth (lactose broth with Triton X-100, LB-T), universal pre-enrichment (UP) broth, and buffered peptone water (BPW). Five different meat analog products (coded A-E) were inoculated with Salmonella serotypes (S. Enteritidis or S. Agona) following the Food and Drug Administration Method Modification and Method Extension Criteria for Existing …

Identification Of Tuna Species In Raw And Processed Products Using Dna Mini-Barcoding Of The Mitochondrial Control Region, Jiahleen Roungchun, Amanda M. Tabb, Rosalee S. Hellberg

Food Science Faculty Articles and Research

Accurate species identification methods are needed to combat tuna fraud, improve tuna stock regulation, and mitigate health risks associated with mislabeled tuna products. The objective of this study was to conduct a market survey of raw and processed tuna products using a DNA mini-barcoding system based on the mitochondrial control region (CR). A total of 80 samples of raw, dried, and canned tuna products were collected at the retail level for CR mini-barcoding analysis. The samples underwent DNA extraction, polymerase chain reaction (PCR), and DNA sequencing of the 236-bp CR mini-barcode. The resulting sequences were searched against GenBank using the …

Assessing The Efficacy Of Bacteriological Analytical Manual (Bam) Enrichment Broths For Detection Of Salmonella Spp. In Meat Analogs, Georgia Sampson

Food Science (MS) Theses

Plant-based meat alternatives are gaining popularity as the number of market options increases. However, the recent appearance of these products on the market post-dates the validation of the current approach for isolating Salmonella from meat analogs. Therefore, the objective of this study was to compare the efficacy of the currently used Bacteriological Analytical Manual (BAM) pre-enrichment broth (lactose broth) with two additional broths (universal pre-enrichment broth and buffered peptone water) for the detection of Salmonella in five plant-based burger products. Each burger product was spiked with a Salmonella serotype (S. Enteritidis or S. Agona) that has previously been linked …

Authentication Of Red Snapper (Lutjanus Campechanus) Fillets Using A Combination Of Real-Time Pcr And Dna Barcoding, Rachel B. Isaacs, Rosalee S. Hellberg

Food Science Faculty Articles and Research

Red snapper (Lutjanus campechanus) is a historically overfished and highly valued species that is commonly substituted with other fish, such as tilapia, rockfish, and other snapper species. The objective of this study was to assess the ability of real-time PCR to be used as a screening tool to rapidly test commercial fillets for the presence of red snapper, followed by species identification of negative samples with DNA barcoding. A total of 24 frozen, fresh, or thawed (previously frozen) fillets labeled as “red snapper” were tested with real-time PCR, along with 54 fillets from fish that are common substitutes …

Inspecting Species And Freshness Of Fish Fillets Using Multimode Hyperspectral Imaging Techniques, Jianwei Qin, Fartash Vasefi, Rosalee S. Hellberg, Alireza Akhbardeh, Rachel B. Isaacs, Ayse Gamze Yilmaz, Chansong Hwang, Insuck Baek, Walter F. Schmidt, Moon S. Kim

Food Science Faculty Articles and Research

This study developed multimode hyperspectral imaging techniques to detect substitution and mislabeling of fish fillets. Line-scan hyperspectral images were collected from fish fillets in four modes, including reflectance in visible and nearinfrared (VNIR) region, fluorescence by 365 nm UV excitation, reflectance in short-wave infrared (SWIR) region, and Raman by 785 nm laser excitation. Fish fillets of six species (i.e., red snapper, vermilion snapper, Malabar snapper, summer flounder, white bass, and tilapia) were used for species differentiation and frozen-thawed red snapper fillets were used for freshness evaluation. A total of 24 machine learning classifiers were used for fish species and freshness …

Detection Of Fish Fillet Substitution And Mislabeling Using Multimode Hyperspectral Imaging Techniques, Jianwei Qin, Fartash Vasefi, Rosalee S. Hellberg, Alireza Akhbardeh, Rachel B. Isaacs, Ayse Gamze Yilmaz, Chansong Hwang, Insuck Baek, Walter F. Schmidt, Moon S. Kim

Food Science Faculty Articles and Research

Substitution of high-priced fish species with inexpensive alternatives and mislabeling frozen-thawed fish fillets as fresh are two important fraudulent practices of concern in the seafood industry. This study aimed to develop multimode hyperspectral imaging techniques to detect substitution and mislabeling of fish fillets. Line-scan hyperspectral images were acquired from fish fillets in four modes, including reflectance in visible and near-infrared (VNIR) region, fluorescence by 365 nm UV excitation, reflectance in short-wave infrared (SWIR) region, and Raman by 785 nm laser excitation. Fish fillets of six species (i.e., red snapper, vermilion snapper, Malabar snapper, summer flounder, white bass, and tilapia) were …

Microplate Immunocapture Coupled With The 3m Molecular Detection System And Selective Plating For The Rapid Detection Of Salmonella Infantis In Dry Dog Food And Treats, Danielle K. Rosen, Miguel Gallardo, Mcclain Vail, Rosalee S. Hellberg

Food Science Faculty Articles and Research

The objective of this study was to use microplate immunocapture (IC) to reduce the enrichment time required for detection of Salmonella in pet food with the 3 M Molecular Detection System (MDS) or selective plating on XLD. Dog food and pig ear treats were inoculated with Salmonella Infantis at concentrations of 10⁰–10⁴ CFU/25 g, followed by a 3-h enrichment, then microplate IC and 3 M MDS or microplate IC and selective plating on XLD. Another set of samples underwent a traditional 24-h enrichment followed by 3 M MDS or selective plating. Based on the results of three …

Labeling Compliance And Species Authentication Of Fish Fillets Sold At Grocery Stores In Southern California, Priscila Liou, Angela Banda, Rachel B. Isaacs, Rosalee S. Hellberg

Food Science Faculty Articles and Research

Seafood mislabeling has numerous consequences, including economic deception and food safety risks. The focus of this study was to investigate fish species labeling, use of acceptable market names, and Country of Origin Labeling (COOL) compliance for fresh fish fillets sold at grocery store seafood counters in Southern California. A total of 120 fillets representing 16 different categories of fish were collected from 30 Perishable Agricultural Commodities Act (PACA)-listed grocery stores. Each sample underwent DNA barcoding to identify the species. Acceptable market names were confirmed using the FDA Seafood List. Samples were determined to be compliant with COOL if both …

Use Of Gamma Irradiation As An Intervention Treatment To Inactivate Escherichia Coli O157:H7 In Freshly Extracted Apple Juice, Dielle Aurelia Fernandes

Food Science (MS) Theses

Escherichia coli O157:H7 can contaminate dropped apples used for juicing via contact with manure or fecally tainted irrigation water and attach to the flesh of the apple through bruises and wounds where surface sanitizers are not effective. The goal of this project was to determine the efficacy of gamma irradiation at the maximum allowed dose of 1000 Gy to inactivate Escherichia coli O157: H7 in whole apples used for juicing. Whole apples were punctured to simulate wounds which were then inoculated with an outbreak strain of E.coli O157:H7 and subjected to gamma irradiation at doses upto 1000 Gy. The D-value …

Concentration Of Listeria Monocytogenes In Skim Milk And Soft Cheese Through Microplate Immunocapture, Steven A. Rogers, Melissa Calicchia, Rosalee S. Hellberg

Food Science Faculty Articles and Research

Microplate immunocapture is an inexpensive method for the concentration of foodborne pathogens using an antibody-coated microplate. The objective of this study was to determine the efficacy of microplate immunocapture as an alternative to traditional enrichment for concentrating Listeria monocytogenes to levels detectable with selective plating or real-time PCR. L. monocytogenes isolates serologically characterized as Type 1 (1/2a) and Type 4 (untypeable) were grown overnight and diluted to 10⁰ to 10⁶ colony-forming units (CFU)/mL. The isolates were used to optimize microplate immunocapture in tryptic soy broth with 0.6% yeast extract (TSBYE), skim milk, and queso fresco samples. Following …

Comparison Of Real-Time Pcr And Elisa-Based Methods For The Detection Of Beef And Pork In Processed Meat Products, Adam T. Perestam, Kayleigh K. Fujisaki, Omar Nava, Rosalee S. Hellberg

Food Science Faculty Articles and Research

Two commonly used methodologies for species detection within processed meat products are real-time polymerase chain reaction (PCR), a DNA-based method, and enzyme-linked immunosorbent assay (ELISA), a protein-based method. In this study, a real-time PCR assay was compared to a commercial ELISA kit based on sensitivity, specificity, agreement among duplicate samples, cost, time, and ease of use. Fifteen reference samples containing known percentages (0.1–99.9%, w/w) of pork and beef were analyzed in duplicate using both methods. Thirty commercial products, including sausages, pet treats, and canned meats, were also tested in duplicate with each method. Reference sample analysis showed real-time PCR was …

Use Of The Mitochondrial Control Region As A Potential Dna Mini-Barcoding Target For The Identification Of Canned Tuna Species, Jacquelyn K. Mitchell, Rosalee S. Hellberg

Food Science Faculty Articles and Research

In this study, a DNA mini-barcoding methodology was developed for the differentiation of species commonly found in canned tuna. Primers were designed to target a 236-base pair (bp) fragment of the mitochondrial control region (CR) and a 179-bp fragment of the first internal transcribed spacer region (ITS1). Phylogenetic analysis revealed the ability to differentiate 13 tuna species on the basis of the CR mini-barcode, except in a few cases of species introgression. Supplementary use of ITS1 allowed for differentiation of introgressed Atlantic bluefin tuna (Thunnus thynnus) and albacore tuna (Thunnus alalunga), while differentiation of introgressed Atlantic …

Effect Of Green Tea On Interaction Of Lipid Oxidation Products With Sarcoplasmic And Myofibrillar Protein Homogenates Extracted From Bovine Top Round Muscle, Nahathai Stapornkul, Tatiana Prytkova, Lilian Were

Food Science Faculty Articles and Research

The interaction between lipid oxidation products and bovine sarcoplasmic (SP) and myofibrillar protein (MP) homogenates in the presence of green tea was investigated. To monitor the effect of green tea on lipid oxidation, aldehydes were measured while effect on protein was monitored via changes in myoglobin, thiols, and tryptophan fluorescence over nine days of refrigerated storage. The presence of SP and MP decreased free aldehydes in the buffers. The SP bound more aldehydes than MP. The tea compounds exhibited more favorable binding energies than aldehydes near histidine 64 close to the heme moiety of myoglobin. Addition of tea lowered tryptophan …

Effect Of Phytosanitary Irradiation And Methyl Bromide Fumigation On The Physical, Sensory, And Microbiological Quality Of Blueberries And Sweet Cherries, Karen Thang, Kimberly Au, Cyril Rakovski, Anuradha Prakash

Food Science Faculty Articles and Research

Background

The objective of this study was to determine whether irradiation could serve as a suitable phytosanitary treatment alternative to methyl bromide (MB) fumigation for blueberries and sweet cherry and also to determine the effect of phytosanitary irradiation treatment on survival of Salmonella spp. and Listeria monocytogenes on these fruit. ‘Bluecrop’ blueberries (Vaccinium corymbosum) and ‘Sweetheart’ cherries (Prunus avium) were irradiated at 0.4 kGy or fumigated with methyl bromide and evaluated for quality attributes during storage.

Results

Irradiation caused an immediate decrease in firmness of both fruit without further significant change during storage. Fumigated fruit, in …

Antimicrobial Susceptibility Of Listeria Monocytogenes To Bacteriophage Listex™ P100 In Alfalfa Sprouts (Medicago Sativa), Tushar Sawant

Food Science (MS) Theses

The seed germination process during sprout production provides suitable environmental conditions for the growth of pathogenic bacteria, such as Listeria monocytogenes. A potential way to control this bacterial growth is through the use of bacteriophages, which are naturally occurring viruses that specifically attack bacterial targets and have been shown to be effective antimicrobials in some foods. Therefore, the objective of this study was to evaluate the antimicrobial susceptibility of L. monocytogenes to bacteriophage on alfalfa sprouts during seed germination and subsequent refrigerated storage at 4 °C. Alfalfa sprout seeds were dip-inoculated with 5.5 x 105 CFU/ml L. monocytogenes serogroups 1 …

Microbial Safety And Quality Of Fresh Herbs From Los Angeles, Orange County, And Seattle Farmers’ Markets, Donna J. Levy, Nicola K. Beck, Alexandra L. Kossick, Taylor Patti, J. Scott Meschke, Melissa Calicchia, Rosalee S. Hellberg

Food Science Faculty Articles and Research

BACKGROUND: Farmers' markets have been growing in popularity in the United States, but the microbial quality and safety of the food sold at these markets is currently unknown. The purpose of this study was to assess the microbial safety and quality of fresh basil, parsley and cilantro sold at farmers' markets in the Los Angeles, Orange County and greater Seattle areas.

RESULTS: A total of 133 samples (52 basil, 41 cilantro and 40 parsley) were collected from 13 different farmers' markets and tested for Salmonella and generic Escherichia coli. One sample (parsley) was confirmed positive for Salmonella and 24.1% of …

Detection And Identification Of Salmonella Enterica, Escherichia Coli, And Shigella Spp. Via Pcr-Esi-Ms: Isolate Testing And Analysis Of Food Samples, Sarah E. Pierce, Rosalee S. Hellberg, Chorng-Ming Cheng, Kai-Shun Chen, Donna M. Williams-Hill, William B. Martin, Marc W. Allard

Food Science Faculty Articles and Research

An assay to identify the common food-borne pathogens Salmonella, Escherichia coli, Shigella, and Listeria monocytogenes was developed in collaboration with Ibis Biosciences (a division of Abbott Molecular) for the Plex-ID biosensor system, a platform that uses electrospray ionization mass spectroscopy (ESI-MS) to detect the base composition of short PCR amplicons. The new food-borne pathogen (FBP) plate has been experimentally designed using four gene segments for a total of eight amplicon targets. Initial work built a DNA base count database that contains more than 140 Salmonella enterica, 139 E. coli, 11 Shigella, and 36 Listeria patterns and 18 other Enterobacteriaceae organisms. …

1% Calcium Chloride Treatment In Combination With Gamma Irradiation Improves Microbial And Physicochemical Properties Of Diced Tomatoes, Anuradha Prakash, Pei-Chen Chen, Richard L. Pilling, Nicole Johnson, Denise Foley

Food Science Faculty Articles and Research

The purpose of this study was to determine the effect of a combination of a 1% calcium chloride dip with low dose irradiation on microbial populations, and biochemical and physical properties, of fresh diced tomatoes during a two-week storage period. Vine tomatoes at the light-red stage (trial 1) and Celebrity tomatoes at the table ripe stage (trial 2) were diced, dipped in 1% CaCl2, and irradiated at 1 kGy from a Co-60 source. Tomatoes were also contaminated with cocktail of nalidixic-acid resistant Salmonella strains (S. Poona, S. Hartford, S. Gaminara, S. Michigan, and S. Montevideo) and subjected to gamma irradiation. …

Irradiation D Values Of Salmonella Spp. In Diced Tomatoes Dipped In 1% Calcium Chloride, Anuradha Prakash, Nicole Johnson, Denise Foley

Food Science Faculty Articles and Research

Outbreaks of salmonellosis have been associated with eating raw domestic tomatoes. In this study, we examined the efficiency of combined irradiation and a 1% calcium chloride dip to reduce the population of Salmonella enterica strains on diced tomatoes. Tomatoes were contaminated with nalidixic acid-resistant strains of S. Hartford, S. Montevideo, or a mixture of 5 strains (S. Hartford, S. Montevideo, S. Poona, S. Michigan, S. Gaminara). We irradiated tomatoes at various doses up to 0.9 kGy from an electron beam source to conduct a D-value study (decimal reduction time required to eliminate 90% of the organism). Surviving Salmonella populations were …