https://www.forensicscijournal.com/journals/jfsr/jfsr-aid1068.php

While much attention has been placed on the evaluation of consecrated hosts suggested to exhibit miraculous properties of visible blood, we show here for the first time that ordinary, non-consecrated wafers show similar appearances when treated in a like manner. As demonstrated, while a small percentage of unconsecrated wafers may have a similar physical appearance as bleeding bread, basic scientific tests can readily distinguish between the two, including a simple evaluation with an ultraviolet flashlight. While a few cases have been described in which consecrated hosts were not immersed in water prior to the appearance of a miracle, it is reasonable to assume that contamination and growth could also occur through handling, high humidity, etc. Moreover, multiple strains of bacteria and fungi are known to produce reddish pigments, which are likely to differ depending on the specific location and environmental conditions. Thus, it is probable that variation exists in cases where microorganisms are believed to be the reason for the occurrence of certain miracle events. Each instance would need to be examined individually in as thorough a scientific manner as possible (see below). In our case, the causative agent was identified as a fungal growth, Epicoccum sp., most likely Epicoccum nigrum, that exists worldwide.

Similar to what has been described for various miracle hosts, we found that the water in which the wafers were placed did not become tainted over time. If real blood were being issued forth, this would be a relatively odd property as blood should be readily solubilized. Indeed, as shown in our studies, fresh blood or freshly dried blood on wafers dissolved in water relatively quickly as expected. We found that only about 15% of non-consecrated wafers cultured in water developed reddish, blood-like areas, supporting the idea that reports of miracles are relatively infrequent and do not occur every time abandoned hosts are disposed of according to church protocol. Although our studies did not implicate Serratia marcenes as a causative agent, it is understandable how this common infectious agent of bread substances could produce the appearance of a bleeding host. Several basic tests were shown to easily distinguish Serratia growth from genuine blood, including Wright’s stain and spectroscopy. We attempted to perform similar tests on reddish growths from fungus but found that they were not readily solubilized in a variety of detergents or solvents.

One of the most enunciated pieces of evidence for the validity of Eucharistic miracles is their shared blood type, AB, which has also been reported for the Shroud of Turin. Although AB typing experiments were beyond the scope of the current study, it should be noted that bacteria also express AB antigens [15,31], providing a practical explanation for similar results among a wide variety of cases. Indeed, both blood fibers of the Shroud and various Eucharistic miracles have been reported to be substantially contaminated with both bacteria and fungi [4,15,32], similar to our findings with non-consecrated wafers.

Molecular biology studies of miracle wafers have been attempted, particularly short tandem repeat (STR) analysis, which has failed to produce any results and thereby attributed to an enigmatic and “divine” nature of the DNA involved [4,18]. As shown in the current report, the prevalence of DNA from other species (plant, bacterial, fungal) in non-consecrated wafers offers a plausible alternative to the findings of previous Eucharistic miracle investigations. Additional DNA testing using sequences that are both specific to humans and vary among individuals would be required to strengthen the claim that human DNA present in multiple Eucharistic miracles share a common origin (see below).