Salmonella in eggs

World Health Organization. (2002) Risk assessments for salmonella in eggs and broiler chickens. Geneva, World Health Organization. 

We know that much of the recent compunction for consumers to choose organic food has been driven by media attention to food scares , which have popularised the focus on food safety and health. Issues such as salmonella in eggs, E. coli food poisoning and the BSE disaster have all taken their toll on consumers confidence in the food industry. 

Infections such as Salmonella or Campylobacter may not have marked effects on bird health, but when they occur in eggs or meat can present a risk for the human consumer. 

Baron, F., Fauvel, S., and Gautier, M. 1999. Behaviour of Salmonella enteritidis in industrial egg white egg naturally contains factors inhibitory to Salmonella growth. In Egg Nutrition and Biotechnology (J.S. Sim, S. Nakai, and W. Guenter, eds), pp. 417-430. CABI Publishing, Oxon, UK. 

Jung, Y.S. and Bauchat, L.R. 1999. Survival of multidrug-resistant Salmonella typhimurium DT104 in egg powders as affected by water activity and temperature. International Journal of Food Microbiology A9 1-8. 

It is concluded that the modified 1-2 TEST system can be viewed as a reliable rapid screening method for the detection of Salmonella in a variety of naturally contaminated animal feeds, feed ingredients, frozen egg products and environmental samples. 

The major organisms of concern in eggs are Salmonella spp. The level of contamination depends on several factors, such as age, porosity of the shell, the... 

Heat has been widely applied to destroy salmonellae in various food products. The thermal pasteurisation of whole egg, reviewed by Cunningham, is specifically based on the inactivation of 10 to 10 salmonellae (of normal heat resistance) per gramme of product, and is a legal requirement in many countries including United Kingdom (64°C for 2-5 min) China (63 °C for 2 5 min) Australia... 

FDA was also very slow in responding to the problem of Salmonella-contaminated eggs. In 1999, FDA announced an Egg Safety Action Plan, and it spent the next five years drafting proposed regulations. After FDA completed the final rule in July 2008, OIRA held it up for the remainder of the Bush Administration. One consequence of the unwarranted delay was a massive Salmonella outbreak in August 2010 that sickened more than 1,200 people and resulted in a recall of more than one-half billion eggs. ... 

Specifications. Typical specifications are indicated in Table 7 for Hquid, frozen, and dried egg products. Every lot of egg product is tested for moisture, pH, total bacteria count, coliform, yeast and mold, and Salmonella. 

Valentfn-Bon, I. E. Brackett, R. E. Seo, K. H. Hammack, T. S. Andrews, W. H. Preenrichment versus direct selective agar plating for the detection of Salmonella enteritidis in shell eggs. J. Food Prot. 2003, 66,1670-1674. 

Present scientific evidence indicates that transmission of enteric pathogens (particularly Campylobacter) is mainly horizontal, while vertical transmission from parent to progeny via the egg is considered much less likely. Studies have shown that that the majority of Salmonella and Campylobacter strains do not cause disease symptoms in poultry and that between 40% and 80% of chicken flocks are Campylobacter positive. 

The Centers for Disease Control (CDC) in the USA has estimated that Campylobacter and Salmonella are the top two bacterial foodbome pathogens as they are responsible for a total of 2 and 1.3 million foodbome infections every year (Mead et al., 1999). Most of the cases of infection with Campylobacter and Salmonella appear to be due to eggs and poultry, but a significant number of cases are related to beef products (CDC, 2005 Jay, 2000). EHEC does not cause as many infections as the top two pathogens (approximately 100,000 in the USA), but EHEC is frequently linked to outbreaks of diarrhea caused by the consumption of contaminated ground beef (Mead et al., 1999, Rangel et al., 2005). Infections caused by EHEC are the major microbial public health concern related to ruminant food products. 

Sugita-Konishi, Y., Sakanaka, S., Sasaki, K., Juneja, L., Noda, T., and Amano, F. (2002). Inhibition of bacterial adhesion and salmonella infection in BALE/c Mice by sialyloligo-saccharides and their derivatives from chicken egg yoUc. /. Agric. Food Chem. 50, 3607-3613. 

Salmonella rods are present on the surfaces of eggs and may penetrate into eggs via shell pores. They are also found in poultry and milk, and may contaminate meat during jointing. Foodborne toxicoinfections caused by Salmonella rods, but not involved in typhus or paratyphus, are named salmonellosis. In 2001 in Poland, the morbidity rate reached 51.2 per 100,000 (19,788 cases) (Gonera,... 

Seo et al. (1999) used a planar optic biosensor that measures the phase shift variation in refractive index due to antigen binding to antibody. In this method, they were able to detect S. enterica serovar T) himurium with a detection limit of 1 x 10 cfu/ml. When chicken carcass fluid was inoculated with 20 cfu/ml, the sensor was able to detect this pathogen after 12 h of nonselective enrichment. A compact fiber optic sensor was also used for detection of S. T) himurium at a detection limit of 1 X 10" cfu/ml (Zhou et al., 1997, 1998) however, its efficacy with food samples is unproven. Later, Kramer and Lim (2004) used the fiber optic sensor, RAPTOR , to detect this pathogen from spent irrigation water for alfalfa sprouts. They showed that the system can be used to detect Salmonella spiked at 50 cfu/g seeds. An evanescent wave-based multianalyte array biosensor (MAAB) was also employed for successful testing of chicken excreta and various food samples (sausage, cantaloupe, egg, sprout, and chicken carcass) for S. T) himurium (Taitt et ah, 2004). While some samples exhibited interference with the assay, overall, the detection limit for this system was reported to be 8 x 10 cfu/g. 

Rijpens, N., Herman, L., Vereccken, F., Jannes, G., De Smedt, J., and De Zutter, L. (1999). Rapid detection of stressed Salmonella spp. in dairy and egg products using immunomagnetic separation and PCR. Int. J. Food Microbiol. 46,37M4. 

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