Mold exposure and mycotoxin
Bakery wastes are prone to molds. Feeding rotten bakery wastes to livestock is detrimental. In 1892, it was reported to cause nervous disorders, anormal salivation, increased heart beat frequency, blindness and even death in growing pigs and horses (Cornevin, 1892).
Zearalenone
The EFSA reported that cereal products, among which bread and fine bakery wares, made the largest contribution to the estimated zearalenone exposures. Zearalenone is a mycotoxin produced by a cereal fungus of the Fusarium genus. Pigs are particularly sensitive to zearalenone that has several oestrogenic effects (EFSA, 2011).
Bacterial contamination
Botulism
In 2001 in Canada, an outbreak of botulism occurred in a herd of feedlot cattle that had been fed on different carbohydrate wastes, i.e. potato waste and bakery waste. Clinical signs of botulism were lower feed intake, malodorous faeces, progressive weakness, ataxia, recumbency, and death. Out of 795 animals, 52 were ill and 14 died. The bakery waste was considered the likely source of the toxin and was found positive for the presence of Clostridium botulinum type D. Two days after the removal of bakery waste from the diet, there were no new reported cases of botulism in the feedlot (Heider et al., 2001). This was the unique case of Clostridium botulinum contamination of bakery waste. Toxin discharge probably occurred since heavy rains provided suitable anaerobic conditions for Clostridium previously present in bakery waste (Heider et al., 2001).
Dioxine contamination
During the late 1990s several incidents of dioxin contamination in bakery waste used for feed were reported in Germany and the Netherlands. The amount of dioxin in bakery waste was 15 times over the current limit (12 ng TEQ/kg vs. 0.75 ng TEQ/kg). Contamination was reported to be due to the waste firewood used to dry bakery waste (Hoogenboom et al., 2004).