Eggshell Strength Test Method

Eggshell Strength Test Method

The eggshell is the outer casing of eggs laid by oviparous animals. It is thin yet sturdy, serving to prevent water evaporation, resist mechanical damage, and supply calcium required for skeletal development. It is mainly composed of calcium carbonate (accounting for 91%–95%), magnesium carbonate, calcium phosphate, and organic substances (such as proteins and mucopolysaccharides). Among these, calcium carbonate exists in the form of calcite, which binds with the protein fiber matrix during calcium deposition to form a rigid structure. Microscopically, the eggshell consists of a mammillary layer, a spongy layer, and a cuticle layer, forming a hierarchically ordered mineralized structure that is lightweight and pressure-resistant.

Due to its properties, eggshells are commonly used in ceramic production as a raw material substitute for calcite. They are also applied in preparing bone repair nanomaterials, and serve as dietary calcium fortifiers, feed additives, and components of eco-friendly plastic substitutes.

Experimental Purpose

Eggshell strength refers to the ability of an eggshell to resist fracture and withstand maximum pressure when subjected to external force. It is a key indicator for evaluating the external quality of eggs, covering the entire industrial chain from breeding, processing, logistics to consumption, and is of great significance for improving industrial efficiency and ensuring food safety.

The main functions are as follows:

①Reduce transportation and storage loss: Insufficient eggshell strength easily leads to cracking caused by collision or stacking pressure, resulting in direct economic losses and potential contamination risks. Testing allows the selection of high-strength eggs for long-distance transportation to reduce breakage rates.

②Ensure food safety and consumption experience: Damaged eggshells are prone to microbial invasion, accelerating spoilage and posing food safety hazards.

③Optimize breeding management and feed formulation: Eggshell strength is affected by nutrients such as calcium, phosphorus, and vitamin D₃. Regular testing can guide the adjustment of feed ratios to improve eggshell quality.

④Poultry breeding: By breeding individuals with excellent eggshell strength, superior breeds with higher breakage resistance can be gradually developed.

⑤ Monitor flock health: An abnormal drop in eggshell strength may be an early sign of diseases such as Newcastle disease and infectious bronchitis, facilitating timely intervention.

⑥Promote scientific research and standardization: Provide reliable data for universities and research institutions to study eggshell formation mechanisms, nutritional physiology, and environmental impacts; meanwhile, support quality inspection departments in market supervision.

Experimental Equipment

①ST120H Eggshell Strength Tester

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Experimental Procedures

①Inspect the instrument and test samples to ensure they are clean, dry, and free from contamination.

② Connect the power supply, turn on the instrument, and preheat for 5–10 minutes to stabilize the sensor.

③ Select fresh, crack-free eggs of uniform size. Equilibrate the samples in a standard environment (temperature 20±2℃, humidity 50±5% RH) for 2 hours to eliminate environmental effects on eggshell performance. Place the egg with the large end upward steadily on the egg holder or positioning slot of the instrument base, ensuring the egg is vertical.

④ Press the "Start" button to initiate the testing program. The probe slowly presses down on the top of the eggshell at a constant speed. At the moment the eggshell fractures, the instrument automatically records the maximum pressure value and stops loading.

⑤ Read and record the value. Repeat the measurement 1–3 times and calculate the average value for better representativeness.

⑥ Clean up residual egg liquid.

Experimental Analysis

Based on multiple tests, the average eggshell strength of the randomly selected samples in this experiment is 3.5 kg/cm², approximately 34.3 N, meeting the standard for commercial eggshell strength.