Évelin Francine Wigmann

Influence of storage temperature on growth of Penicillium polonicum and Penicillium glabrum and potential for deterioration of frozen chicken nuggets

The practice of freezing food is one of the main processes used by the industry to prolong the shelf life of foods. Its use has expanded in recent years due to the increased consumption of convenience products, many of which are sold in frozen form. The temperature at which these foods are maintained during marketing in supermarkets or stored in the consumers home is critical to ensure microbiological stability of products. Temperature abuse can allow microbial growth, especially growth of filamentous psychrophilic fungi. Besides economic losses in the industrial sector due to the return of products and loss of confidence by consumers, the development of fungi in foods is a public health problem due to the possibility of mycotoxin production. The aim of this study was to assess the growth at temperatures of 5, 0, -5 and -18°C for two species of fungi involved in the deterioration of frozen chicken nuggets, Penicillium polonicum (33/12 NGT) and Penicillium glabrum (29/12 NGT), inoculated both in culture medium and in the food. The results demonstrated that P. polonicum was able to form microcolonies on potato dextrose agar plates at 0°C and form visible colonies on the surface of the frozen chicken nuggets kept at -5°C for 120 days, regardless of brand. For P. glabrum the limiting growth temperature was 5°C in the culture medium and 0°C on frozen chicken nuggets, regardless of the brand analyzed. Thus, it is essential to adhere to the storage temperatures recommended to ensure the stability and safety of this food product.

Survival of Penicillium spp. conidia during deep-frying and baking steps of frozen chicken nuggets processing

This study aimed at determining whether Penicillium spp. strains could survive through the heat treatment applied during the processing of frozen chicken nuggets. Firstly, it was found that the conidia of Penicillium were not able to survive the heat shock in phosphate buffer at pH 7.2 in thermal death tubes (TDT) at 80 °C/30 min. Subsequently, each Penicillium strain was inoculated in frozen chicken nuggets, which were subjected to the following treatments: i) only deep frying (frying oil at 195-200 °C), ii) only baking (120-130 °C until the internal temperature reached 70 °C) and iii) deep frying followed by baking (frying oil temperature of 195-200 °C and baking temperature of 120-130 °C, until the internal temperature reached 70 °C). The results indicated that Penicillium polonicum NGT 23/12, Penicillium commune NGT 16/12, Penicillium solitum NGT 30/12 and Penicillium crustosum NGT 51/12 were able to survive after the combined treatment (deep frying followed by baking) when inoculated in chicken nuggets. P. polonicum NGT 23/12 was the most resistant strain to the combined treatment (deep frying and baking), as its population was reduced by 3 log cycles CFU/g, when the internal temperature reached 78 °C after 10 min and 30 s of baking. The present data show that if Penicillium spp. is present in high numbers in raw materials, such as breading flours, it will survive the thermal processing applied during chicken nuggets production.

Suscetibilidade de Aspergillus Spp. A Ácidos Orgânicos Conforme O Ph

Maria de Jesus Alcano, Raquel Carine Jahn, Catia Daiane Scherer, Evelin Francine Wigmann, Fernanda Saccomori, Vivian Machado Moraes, Marcelo Valle Garcia, Marina Venturini Copetti. Suscetibilidade de Aspergillus spp. a Acidos Orgânicos Conforme o pH. In: Anais do 12o Congresso Latinoamericano de Microbiologia e Higiene de Alimentos MICROAL 2014 [= Blucher Food Science Proceedings, num.1, vol.1]. Sao Paulo: Editora Blucher, 2014. DOI 10.5151/foodsci-microal-313 Suscetibilidade de Aspergillus spp. a Acidos Orgânicos Conforme o pH