We investigated the usefulness of a method for evaluation of food hardness using a plastic bottle （PB method） in home cooking, which does not require special equipment or techniques. UDF foods and six commercially prepared foods were used for the measurements. A PET bottle filled with water with a total weight of 400 g （equivalent to 200 kPa） was fitted with a special cap with a 5 mm diameter convex part. The bottle was turned upside down and pushed under its own weight to see if the convex part of the cap penetrated the sample. If it penetrated, the sample was evaluated as crushable by the gums. The hardness was also measured to check if it corresponded to Category 2 （crushable by gums） of the UDF food. The results of both tests were combined to evaluate the hardness （crushable with gums） of the samples. In the case of UDF foods, the PB method and physical property measurement evaluations were the same. In commercially prepared foods, it was found that foods easily crushed by the PB method tended to be soft, and that the PB method was evaluated to be safer than the physical property measurement. In conclusion, it was found that not only visual and empirical judgments, but also the PB method to check the hardness of food is useful for safe eating.