Ahmed Abdelhamid

The Ohio State University | OSU · Department of Food Science and Technology

Abstract: Understanding the behavior of microorganisms in food is essential for promoting their growth when needed, inhibiting growth-associated spoilage and toxin production, and eliminating infectious pathogens through processing. Therefore, three behavioral modes are addressed: growth, survival, and death. The first part of the chapter describe...

Biofilms are intricate multicellular structures created by microorganisms on living (biotic) or nonliving (abiotic) surfaces. Medically, biofilms often lead to persistent infections, increased antibiotic resistance, and recurrence of infections. In this review, we highlighted the clinical problem associated with biofilm infections and focused on cu...

Biofilm formation in food processing environment and within equipment increases the risk of product spoilage and contamination with pathogens. Cleaning-inplace (CIP) operations are useful in removing soils and in sanitizing processing equipment, including eliminating biofilms. However, CIP is a resource-intensive process, particularly in the usage...

Pasteurization of shell eggs is an important technology designed to protect consumers against Salmonella Enteritidis that contaminates this commodity. A low heating rate is preferred over a high rate during shell egg thermal pasteurization due to product quality concern.

The coronavirus disease 2019 (COVID-19) has resulted in tremendous human and economic losses around the globe. The pandemic is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a virus that is closely related to SARS-CoV and other human and animal coronaviruses. Although foodborne diseases are rarely of pandemic proportion...

Contribution of food vehicles to pathogenicity of disease-causing microorganisms is an important but overlooked research field. The current study was initiated to reveal the relationship between virulence of Salmonella enterica serovar Enteritidis and egg yolk as a hosting medium. Mice were orally challenged with Salmonella Enteritidis cultured in...

Production of some antimicrobial peptides by bacterial producers is a resource-intensive process, thus, using inexpensive growth media and simplifying antimicrobial extraction and down-stream processing are highly desirable. Acid whey, a dairy industry waste, is explored as a medium for production of broad–spectrum antimicrobials from selected bact...

Some Salmonella enterica serovars are frequently associated with disease outbreaks in low-moisture foods (LMF) due to their ability to adapt efficiently to desiccation stress. These serovars are often persistent during food processing. Disruption of these resistance responses was accomplished previously using the membrane-active lipopeptide, paenib...

Bifidobacterium bifidum is one of the most abundant members of the gut microbiota at the early stage of life. The established association of the bacterium with the human gut confers health benefits. Such successful persistence of B. bifidum necessitates metabolic adaptation to the host–derived carbohydrates, a process which is poorly understood. Th...

Salmonella enterica serovar Enteritidis ODA 99‐30581‐13 is a relatively heat-resistant strain isolated from shell eggs. The strain has a 4,777,965-bp genome sequence (52.1% GC content) that was predicted to encode 4,455 proteins, including heat stress response proteins and stress response regulators; these may be involved in its heat resistance.

Salmonella enterica contaminates many food matrices, particularly poultry products. This study was initiated to characterize newly isolated lytic Salmonella phages and to evaluate their efficiency against S. enterica serovar Enteritidis and Typhimurium in liquid whole eggs. Two phages (OSY-STA and OSY- SHC) isolated from livestock farms in Ohio, US...

Some Salmonella enterica strains survive well in low-water activity (low-aw) foods and cause frequent salmonellosis outbreaks in these products. Methods are needed to overcome such desiccation-resistant Salmonella and to improve the safety of low-aw foods. Building on a recent finding, we hypothesized that natural antimicrobial food additives, whic...

Salmonella enterica serovar Livingstone 1236H was isolated originally from peanut butter and represents a health risk in low-moisture foods. The current work presents the strain’s genome sequencing results, which show a 4,824,729-bp genome sequence and 4,435 protein coding sequences, including some that are involved in adaptation to low-moisture en...

Conjunctivitis, caused by bacterial infections, represents health concern and diagnosis of the disease is pivotal for the proper selection of the treatment. The main causes of bacterial conjunctivitis vary in different countries. The current study investigated the common bacterial causes of bacterial conjunctivitis from eye clinics' attendants and...

Foodborne diseases represent a global health threat besides the great economic losses encountered by the food industry. These hazards necessitate the implementation of food preservation methods to control foodborne pathogens, the causal agents of human illnesses. Until now, most control methods rely on inhibiting the microbial growth or eliminating...

Bacteriophage OSY-STA is a new anti- Salmonella phage that was isolated from a chicken farm in Ohio. It is a promising candidate for food safety applications, considering its efficiency in infecting several Salmonella enterica serovars. The current work presents its genomic characteristics. S almonella phage OSY-STA has a 111,039-bp genome and 166...

Some Salmonella enterica serovars adapt effectively to low-water activity (low-aw) environments but this desiccation stress also induces collateral responses that have not been fully explored. Additionally, it is not known how long these responses are retained during refrigerated storage of the dehydrated pathogen. To investigate these issues, two...

Helicobacter pylori infection, a cause of gastric disease, is generally eradicated with standard antibiotic therapy. However, adding probiotics to standard therapy may improve rates of eradication and adverse effects. Despite the growing interest in probiotics in this area, data should be carefully interpreted before evidence-driven decision-making...

Background Probiotics belonging to Lactobacillus and Bifidobacterium spp. have been exploited for their health benefits in treatment and prevention of many pathological conditions and promoting human health. Recent advances in understanding probiotics-human interaction through microbiome research in the context of various medical conditions suggest...

Salmonella enterica adapts effectively and persists for a long time in low-a w foods or environments through resistance mechanisms to desiccation stress. Desiccation-resistant cells compromise food safety and constitute a serious health hazard. Strategies to combat desiccation resistance in S. enterica are needed to sensitize the pathogen to lethal...

Bacteriophages have been envisioned as tools to control a variety of foodborne pathogenic bacteria. Salmonella is a foodborne pathogen that is a threat to public health around the world. Contaminated tomatoes have been associated with several Salmonella outbreaks. Hence, the objective of this work was to identify and characterize different lytic ba...

Bacillus velezensis OSY-GA1 is a Gram-positive soil bacterium that exhibits antagonistic activities against Gram-positive and Gram-negative foodborne pathogens. Here, we present the strain's draft genome, which is 4,009,999 bp long with an average GC content of 46.2%. Genome mining analysis revealed numerous biosynthetic gene clusters encoding anti...

The sharp increase in antibiotic resistance imposes a global threat to human health and the discovery of effective antimicrobial alternatives is needed. The use of probiotics to combat bacterial pathogens has gained a rising interest. Pathogenic Escherichia coli is causative of multiple clinical syndromes such as diarrheal diseases, meningitis and...

Escherichia coli is considered one of the most frequent causative agents of common bacterial infections worldwide. In addition, effective treatment and prevention measures are still in demand due to the rise of antibiotic resistance and the emergence of new virulent strains. In this work, we evaluated antibiotics and bacteriophages as interventions...

The Current study revealed the natural occurrence of toxigenic fungi and mycotoxins production in grains in Saudi Arabia. Samples of yellow corn, white rice and red corn grains were collected from different local markets. Three fungal isolates were isolated from the examined corn grains using PDA media. The toxigenic Alternaria spp. was the most pr...

Omega-3 fatty acids, including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have beneficial effects on human health. The probiotic bacterium E. coli Nissle is unable to produce either EPA or DHA. E. coli Nissle was transformed with the pfBS-PS plasmid carrying the EPA/DHA gene cluster, previously isolated from a marine bacterium. The...

Cucumber mosaic virus (CMV) was isolated from naturally infected Banana, Geranium and Gladiolus and exhibited different external symptoms. The three CMV isolates were transmitted by sap inoculation with 6, 5 and 5 out of 10 inoculated N. glutinosa plants as well as by aphids with 6, 5 and 4 out of 10 inoculated Cucumber plants, respectively. These...

Malformative features of the Potato Tuber Moth (PTM) pupae infested by Phthorimaea operculella Granulovirus (POGV) were shown to little extend by the macro morphological criteria depending on the naked eye based vision to follow changes in size, shape and color. As defined in this work, image processing and analysis proved to be useful for evaluati...