Foodborne Illness and Preventive Strategies

Microbes or chemical contaminants may enter the food chain at any point from farm to fork, causing foodborne illnesses. Different factors such as an individual's susceptibility and a microbe’s pathogenicity lead to a varying degree of disease severity. In this article, explore the different biological and chemical agents responsible for foodborne illness, its symptoms and detection methods, and strategies to prevent and control food poisoning.

A fork displaying diverse bacteria and viruses, emphasizing the risks of foodborne illness and the need for preventive measures. — Foodborne illness may occur from consuming foods or beverages infected with pathogenic microorganisms, such as bacteria, viruses, fungi, and parasites.
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What Is Foodborne Illness?

Foodborne illness or food poisoning is a condition caused by consuming foods or beverages that contain infectious microbial pathogens or harmful chemical contaminants. Food poisoning is either contagious or toxic in nature, which may lead to wide ranging symptoms, from mild indisposition to serious life-threatening conditions. Individuals aged 65 years and above, children below 5 years of age, and immunocompromised individuals are among the most susceptible to severe illness.

Infographic depicting foodborne illness causes, detection methods, prevention strategies, and symptoms (e.g. dehydration, fever, nausea and vomiting, abdominal pain, and diarrhea) — Foodborne illnesses can be caused by biological agents such as microbes and chemical contaminants such as arsenic, cadmium, mercury, and lead, with gastric and immune symptom severity ranging from uncomfortable to life-threatening. Scientists use methods such as microbial culture, immunoassays, PCR, sequencing, mass spectrometry (MS), and biosensors to detect food contamination, and research also enables prevention strategies such as food sanitation, early detection, and agricultural interventions.
Modified from © iStock, BrownAlex, Bezvershenko, Rudzhan Nagiev

Biological and Chemical Contaminants

Different biological agents including bacteria, yeast, fungi, and parasites, and chemical contaminants may cause symptoms ranging from gastric conditions to fatal renal, hepatic, and neurological infections.^1,2

Common foodborne illness contaminants include the following.

Bacteria: Among different microbial types, bacterial pathogens (e.g., Salmonella, Staphylococcus aureus, Clostridium botulinum, Shiga toxin-producing E. coli (STEC), Listeria monocytogenes, and Vibrio cholerae) are the most common etiologic agents responsible for severe food poisoning.³
Yeast: Although yeast are sometimes intentionally used to produce certain foods and drinks, some pathogenic species including Zygosaccharomyces bailii, Pichia membranifaciens, and Dekkera bruxellensis may infect food products such as wine and grape juice concentrate and cause foodborne illness.⁴
Fungi: Filamentous fungi including Aspergillus, Penicillium, and Fusarium species produce mycotoxins that may infiltrate the food chain directly or indirectly, through crop plant infection or food spoilage.⁵ Consumption of mycotoxin-contaminated products leads to acute or chronic food poisoning.
Viruses: Several viruses including hepatitis virus and norovirus (NoV) cause foodborne diseases.⁶
Parasites: Certain parasitic species such as Giardia lamblia, Toxoplasma gondii, and Entamoeba histolytica may be present in unfiltered drinking water and cause intestinal parasitic infection, which impairs children’s growth.⁷
Toxic chemicals: Environmental contaminants may enter the food cycle during agricultural production, such as through water or soil that contains naturally occurring heavy metals, including arsenic, cadmium, mercury, and lead.² In addition, ingestion of pesticide and veterinary drug residues leads to foodborne diseases.

Table 1: Examples of contaminants causing foodborne illness

Contaminant	Type	Food sources	Symptoms	Onset time post-ingestion
Bacillus anthracis	Bacteria	Undercooked contaminated meat	Nausea, vomiting, bloody diarrhea, and acute abdominal pain	2 days to weeks
Clostridium botulinum	Bacteria	Home-canned food with low acid content, baked potatoes in aluminum foil, and foods held warm for a long time in the oven	Vomiting, diarrhea, blurred vision, dysphagia, and descending muscle weakness	12-72 hours
Shiga toxin-producing E. coli (STEC)	Bacteria	Unpasteurized milk, undercooked beef, and contaminated water	Severe diarrhea that could contain blood, abdominal pain, and vomiting	1-8 days
Salmonella spp	Bacteria	Contaminated eggs and poultry, and unpasteurized milk	Abdominal cramps and vomiting; S. typhi and S. paratyphi cause typhoid, which is characterized by fever, headache, constipation, and chills	1-3 days
Cryptosporidium spp	Parasite	Food or water contaminated by an infected handler	Diarrhea (usually watery), stomach cramps, and slight fever	2-10 days
Giardia lamblia	Parasite	Food contaminated by an infected handler after cooking	Diarrhea, stomach cramps, and gas	1-2 weeks

Surge in Foodborne Illness Outbreaks

According to the World Health Organization, approximately 600 million people are infected by foodborne pathogens and 420,000 people die from consuming unsafe food each year. Numerous foodborne illness outbreaks continually occur worldwide. In 2011, a rare enterohemorrhagic E. coli (EHEC) O104:H4 outbreak in Germany and France caused bloody diarrhea and hemolytic uremic syndrome (HUS) in hundreds of individuals.⁸ This outbreak occurred because of high pathogenicity, and bacterial resistance to multiple antibiotics.

Between 2015 and 2018, five European countries and the United Kingdom experienced a Listeria monocytogenes outbreak through the consumption of contaminated frozen corn.⁹ In 2016, a salmonellosis outbreak occurred in Scotland and the Netherlands through poultry and eggs with S. enterica serovar Enteritidis. In 2024, the Food and Drug Administration (FDA) and Centers for Disease Control and prevention (CDC) investigated a Salmonella outbreak in the US linked to contaminated cucumbers grown in Agrotato, Mexico.

Over the years, technological advancements have enabled scientists to determine factors responsible for increasingly common foodborne disease outbreaks worldwide. Key factors include the following.¹⁰

A rapid demographic shift towards an aging population and a high number of immunologically compromised individuals due to a surge in immunosuppressive diseases or treatments
An increased spread of antibiotic resistance
Export and import of fruits, vegetables, and meat without proper microbial safety protocols
Improved transport and storage conditions that may preserve contaminants for longer periods
Changing food habits, such as a high inclination towards consuming raw or undercooked food and bushmeats
Rapid climate change leading to the emergence of novel vectors that quickly spread diseases

Different Methods to Detect Foodborne Contaminants

Scientists have developed various strategies to detect foodborne contaminants, and each technique varies in sensitivity, accuracy, cost, and turnaround time.¹¹

Culture methods

Researchers created multiple culture techniques based on different nutrient media to isolate and identify foodborne pathogens. For example, bismuth sulfite agar (BSA) helps detect Salmonella in food.¹²

Nucleic acid-based methods

Polymerase Chain Reaction (PCR) is a molecular technique that offers quick replication of an organism’s unique DNA sequence.¹¹ A key limitation of this strategy is its ability to process only one DNA sequence at a time. To combat this limitation, scientists developed multiplex PCR and quantitative PCR that can identify multiple pathogens present in a contaminated food sample.

Immunological techniques

Immunological-based strategies use the principle of antibody–antigen interaction.¹³This approach helps detect microbial toxins and pathogens in food samples. Scientists popularly use enzyme-linked immunosorbent assays (ELISA) to identify different foodborne microorganisms including S. enteritidis in milk. The main advantages of ELISA tests are high specificity, simplicity, sensitivity, and cost-effectiveness.

Mass spectrometry

Researchers use mass spectrometry (MS) to detect infectious toxins, such as prions that cause bovine spongiform encephalopathy. Additionally, they specifically use matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) to detect Campylobacter coli and C. jejuni, two common foodborne pathogens.¹⁴

Sequencing

Next-generation sequencing (NGS) helps researchers determine genes responsible for pathogenic virulence and potential aspects of food spoilage.¹⁵ A key advantage of this strategy is that it can identify both culturable and non-culturable microbes.

Scientists use different sequencing strategies, particularly whole genome sequencing (WGS), to characterize foodborne illness causal agents. For example, during the EHEC outbreak in 2011, WGS helped detect a rare combination of virulence genes in enteroaggregative E. coli (attA, aggR, aap, aggA, and aggC, located on a virulence plasmid) and STEC (stx2a).⁸

Biosensors

Scientists design different biosensors for rapid detection of foodborne pathogens.¹⁶ For example, optical biosensors, based on colorimetry, chemiluminescence, fluorescence, and surface plasmon resonance, are highly sensitive and selective to Salmonella species. Besides optical biosensors, scientists have also developed electrochemical biosensors to detect S. aureus, E. coli O157:H7, and C. perfringens.¹⁷

Strategies to Control and Prevent Foodborne Illness

Scientists have come up with different strategies to control foodborne pathogens. Phage therapy uses bacteriophages, which are natural antibacterial agents, to kill target bacteria without harming commensal microflora.¹⁸ The main advantages of phage therapy are its high specificity in targeting bacteria, low toxicity to humans, and self-replicating ability, which ensures a high antibacterial effect even at a low dosage.

Probiotics use living bacteria to reduce pathogen load in the gut.¹⁹ Mechanistically, probiotic formulations enhance the diversity and abundance of gut bacteria that protect the host from foodborne pathogens. Scientists have observed that probiotics can effectively restrict the growth of pathogenic bacteria including S. enteritidis, C. perfringens, C. jejuni, Staphylococcus species, E. coli, and Shigella species.

Antibiotic therapy and vaccines are also viable strategies to combat foodborne illness. For example, researchers have employed an immunization strategy to prevent Salmonella infection by introducing Salmonella-specific antibodies in poultry.²⁰

One can reduce the risks of foodborne illness by following simple sanitation steps, including washing hands, cutting boards, and utensils to remove microorganisms that can adhere to and remain viable on these surfaces for a prolonged time. Eating thoroughly washed fruits and vegetables can also decrease the risk of food poisoning.

National and regional health departments apply modern food safety technologies such as computational genome analysis and genome sequencing to continuously monitor and identify small clusters of foodborne illness.⁸ Early detection can limit outbreaks and reduce the healthcare burden and mortality rates.

References