Celery has shown to be acceptable when it is?

The answer is correct because immersing celery in boiling water for thirty seconds, followed by chilling, is an effective method of blanching. This process helps in preserving the celery's color, texture, and nutritional value while also reducing the microbial load on the surface. Blanching in this way allows for any potential pathogens or spoilage organisms on the surface to be inactivated, making the celery safer for consumption, especially if it is to be stored or processed further.

The chilling phase that follows the immersion in boiling water is equally important as it halts the cooking process, thus preserving the crispness and ensuring that the celery remains fresh. This method of preparation is not only widely accepted but also aligns with good sanitation practices in food handling and preservation.