Food

Foodborne Illness

Salmonella and Campylobacter are both bacteria found in a wide range of animals and foods of animal origin, especially poultry and meats.

In New Zealand these bacteria cause a significant number of infections each year.

Salmonella and Salmonellosis

Image of Salmonella bacteria.

Infection numbers

In 2006, a total of 1335 individuals were reported with Salmonella infection, a rate of 32.3 per 100,000 population, this is a similar rate to that reported in 2005.

Age groups most likely to be affected with Salmonella were:

infants less than one year of age (83 cases reported and an age specific rate of 145.3 per 100,000)
young children age one to four years (280 cases, and rate of 124.2 per 100,000)
adults age 20 to 29 years,(185 cases, 33.5 per 100,000).

Although information is incomplete, individuals identified the following exposures as risk factors for Salmonella infection: consuming food from retail premises

contact with farm animals
consuming untreated water
travelling overseas during the incubation period
contact with other symptomatic people or contact with faecal matter
contact with recreational water.

Links

U.S. Food & Drug Administration Center for Food Safety & Applied Nutrition Foodborne Pathogenic Microorganisms and Natural Toxins Handbook - Salmonella

U.S. Centers for Disease Control and Prevention (CDC)
Brochure about Salmonella and summary of relevant information about Salmonella

Campylobacter

Image of Campylobacter bacteria.

Campylobacter means "curved rod" in Greek. As can be seen above, this is a good description of the shape of these bacteria.

Each one is a slender, spiral-shaped rod, only 1.5 to 3.5 micrometres long - a micrometer is just a thousandth of a millimetre!

Each bacteria has a tail, known as a flagellum, at each end of the cell.

Infection numbers

In 2006, there were 15,873 individuals reported with Campylobacter infection, a rate of 383.5 per 100,000 population, this was a significant increase from the rate of reported disease in 2005, (a rate of 337.6 per 100,000 in 2005).

The age groups most commonly infected were:

young children age one to four years (1227 cases and an age specific rate of 544.2 per 100,000)
adults in the 20-29 year age group (2884 cases, 522.7 per 100,000)
infants under one year of age (237 cases, 415.0 per 100,000).

Not all cases of campylobacter are followed up by public health services and therefore risk factor information is far from complete. Consuming food from retail premises and contact with farm animals were the most frequent risk factors identified.

Links

New Zealand Food Safety Authority (NZFSA)

U.S. Food & Drug Administration Center for Food Safety & Applied Nutrition Foodborne Pathogenic Microorganisms and Natural Toxins Handbook - Campylobacter Jejuni

U.S. Centers for Disease Control and Prevention (CDC)
Summary of relevent information about Campylobacteriosis

U.S. Department of Agriculture / Food Safety and Inspection Service
Information for the public about Campylobacteriosis and its prevention

When to be extra careful

Foodborne diseases are more common in summer and people need to be especially aware of the extra care they should take with the food they prepare and eat. Warmer temperatures allow bacteria to multiply faster on contaminated food resulting in larger doses of bacteria if the food is not properly cooked before being eaten.

Key ways to protect against foodborne illness

1) Reduce bacterial contamination and growth:

store foods at an appropriate temperature out of the 'danger zone' (between 4 deg C and 65 deg C - ie fridge and steaming hot)
do not leave perishable food at room temperature for more than a total of two hours
cook and reheat foods, especially meat and poultry, so they are piping hot throughout
use cooked foods, that have been stored in the refrigerator, within two days
never reheat food more than once
wash all fruit and vegetables thoroughly
freeze foods quickly, thaw in the refrigerator or microwave, avoid re-freezing thawed foods

2) Protect food from cross-contamination through appropriate storage, handling and sanitation:

keep raw and prepared foods separate during preparation, serving and storage
store prepared foods above raw foods in the refrigerator
store foods in covered containers whether in the fridge or the cupboard
keep food storage, preparation areas and equipment clean using hot soapy water. It is a good idea to have separate cutting boards for raw foods such as meat and poultry, and ready to eat foods such as cheese, cooked meats and salads.

3) Ensure good personal hygiene:

ensure adequate personal hygiene including hand washing after handling raw foods, refuse, animals, visiting the toilet or changing nappies
do not cough or sneeze over food
do not smoke when preparing food (handling cigarettes puts saliva and bacteria from skin or lips onto your hands which may then contaminate the food)

Further information

More information on the surveillance of foodborne illness can be found on the ESR website - www.surv.esr.cri.nz

Page last updated: 11 October 2007