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This is the third of a four part screening procedure to find a safe, economical and effective replacement for formaldehyde for sanitizing of hatching eggs. A total of 23 sanitizers were applied at different concentrations and/or exposure times to broiler breeder hatching eggs prior to incubation. In replicate trials, eight groups of 90 hatching eggs per concentration level or per exposure time for each sanitizing procedure were tested. For all treatments except formaldehyde, Virkon, glutaraldehyde (Cidex), and ozone gas, there were three concentrations of sanitizer used: 1) low (half the recommended level); 2) recommended level; or 3) high (twice the recommended level). Eggs were dipped in the solutions for 10 minutes. Virkon was handled similarly, except an additional four-fold application of the recommended level was tested for 10 minutes. Formaldehyde treatments were made using a 1% formalin solution; eggs were dipped for 1, 5, or 10 minutes. Glutaraldehyde was used undiluted for 1 and 10 minutes. Ozone gas (3 levels of concentration) was applied for 3 hours. For all sanitizers tested at recommended levels, there were no gross toxic effects on embryo viability. However, sanitizers that contained components which lowered egg shell porosity (low moisture or weight loss), particularly at the highest concentrations tested, also increased early and late embryo mortality. Active ingredients of sanitizers tested in this study which influenced shell porosity were quaternary ammonia and surfactants (e.g., EDTA). In some cases, a definite “waxy” texture was evident on the eggs. Monitoring moisture loss as a method of assessing a sanitation program has proved to be important.

The necessity of finding a replacement for formaldehyde in commercial hatcheries must include careful assessment of the user and environmental friendliness of the compounds. It would be a pointless exercise to replace existing technology (i.e., formaldehyde fumigation) with an equally toxic procedure, or to replace formaldehyde with an ineffective hatching egg sanitizer. This is the first paper of a series describing the screening procedures applied to 23 different sanitizers available in the market. The procedures outlined may be used to screen or compare other products. Brand names which met our standards for user and environmental friendliness include Bioguard, Germex, Iocide-14, Lysovet, Super Quam, Chlorwash, Quam, Quat 800, 1-Stroke, and Coverage 256. Compounds of questionable user and environmental safety are reported in this paper, and some of these compounds (bleach, peroxide, and ozone) are being used routinely in the industry. In order that a more complete comparison could be made, these compounds were further screened for effectiveness against microbial loads on the egg shell and for toxicity to the embryo.

Twenty three sanitizers were tested for their effectiveness against a “cocktail” of inoculated microorganisms on the egg shell surface. Following inoculation, the eggs were sanitized (using either three concentrations of exposure times per sanitizer), and a sample of a rinse solution from individual eggs was plated on commercially produced biplate media slides (nutrient agar on one side and MacConkey agar on the other). The slides were incubated (37°C) for 48 hours and total colonies were counted. The procedure provided a quick and economical method of assessing the overall effectiveness of a sanitizer against a variety of microorganisms on the egg shell surface. However, the method did not accurately differentiate between either concentration or exposure time of individual sanitization treatments.