Help Your Employees Protect Against Pathogens

The transfer of food pathogens via fomites is accelerated in food processing plants or food service prep kitchens. The microbial ecological dynamics of these specific environments dictate which pathogens will prosper. In general, wet or humid environments with water activities (aw) above 0.90 will enable a lot of non-spore-forming pathogens to prosper.

Dry food handling environments are not guaranteed to be pathogen free. Rather, a shift occurs in the microbial pathogen profile to spore formers and to non-spore formers that readily adapt to drier conditions. These include Staphylococcus aureus, hepatitis A, and the ubiquitous norovirus.6,7

Control programs delineated in GMPs, which should include restriction of street clothes and shoes, proper utilization of hair nets and gloves, and prevention of food handling by ill workers, will markedly improve control of fomite-mediated pathogens.

Environmental control measures for fomite-mediated pathogens also include proper sanitation procedures for all environmental surfaces. This includes use of proper cleaners and sanitizers, as well as both fogging and foaming type disinfection.

A fog unit such as this one can be used to clean a facility in the event of an outbreak of foodborne illnesses.

Oral Tract Body Fluids

As with many communicable diseases, respiratory fluids excreted, sneezed, or coughed from the oral and nasal passages are a major source of food product cross contamination from humans. In addition to the numerous viral particles expelled from respiratory tract fluids, which can include carriers of hepatitis A, there are several key bacterial pathogens of concern.

While tuberculosis carriers in industrialized nations are less prevalent than a century ago, there are more antibiotic-resistant mycobacterial strains. With the preponderance of workers from underdeveloped nations in many food plants, transfer of tuberculosis strains between workers and contamination of perishable ready-to-eat food products are possible in a food operation that lacks a proper screening program for pathogenic strains of tuberculosis.

Several key gram-positive pathogens derived from respiratory tract fluids cannot be screened by even the most thorough employee health programs. Staphylococcal strains, specifically S. aureus, are prevalent in food workers’ respiratory fluids; an estimated 20% of food workers carry toxigenic strains of S. aureus. Other studies have found higher percentages of toxigenic strains. A study of airline catering food handlers found that noses and nasal secretions had higher positive rates of S. aureus than hands.8 These toxigenic strains include methicillin-resistant Staphylococcus aureus, which can be directly transferred to food from workers by fomites and respiratory fluids.

Streptococcal pathogenic strains are also major colonizers of respiratory tract fluids. Most of the group A beta-hemolytic Streptococcus found in food workers are colonized by these pathogens rather than being caused by illness. Sneezing can be a primary mode of streptococcal transmission. Although sneezing or transference of nasal secretions onto food products is the source of streptococcal contamination, it is typically the holding conditions of ready-to-eat handled food products that permit the streptococcal pathogenic strains to grow, leading to foodborne illness outbreaks.9

The most effective control measures involve proper GMP training in personal hygiene, with recognition of the critical role played by respiratory illnesses, cuts, and lesions in transmission to food products of these staphylococcal and streptococcal pathogenic strains.

Urinary, Upper GI Fluids

Excluding urinary tract infections that cause marked illness in food workers, the infectious agents that are a concern include Salmonella strains such as S. typhi from asymptomatic carriers. Hepatitis A caused by intentional contamination of food product by a food service worker has been documented in urine. Such outbreaks, while rare, underscore the need for proper personal hygiene in food workers who have asymptomatic infections.

Upper gastrointestinal tract fluid, specifically vomit, can create a variety of cross contamination vectors on clothing, in restrooms, and on hands or skin. The possible pathogens include norovirus, Salmonella, S. aureus and B. cereus.