1
|
Prada-Ramírez HA, Montes-Tamara JP, Rico-Jimenez EA, Fonseca JC. Stability Study Through Water Activity Measurements for Dispensed Powdered Raw Materials. J AOAC Int 2024; 107:487-492. [PMID: 38218727 DOI: 10.1093/jaoacint/qsae005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 01/03/2024] [Accepted: 01/06/2024] [Indexed: 01/15/2024]
Abstract
BACKGROUND Holding times for raw materials are relevant since they enable us to understand the allowable time that a raw material can be kept under ideal storage conditions before the start of the manufacturing process without its quality attributes being affected. The quantification of water activity can be used as an indicator of the microbiological, physicochemical, and organoleptic stability of a specimen, since low water activity retards autohydrolysis and microbiological growth. OBJECTIVE The main purpose of this investigation was to test the stability of powdered raw materials for a maximum holding time of 8 days through water activity measurements. Thus microbiological, physicochemical, and organoleptic measurements were carried out in parallel and simultaneously to experimentally establish a relationship between the status of the water activity of processed raw materials and the microbiological, physicochemical, and organoleptic results. METHODS The raw materials were stored for a maximum holding time of 8 days, in accordance with United States Pharmacopeia monographs. For all the raw materials tested, water activity measurements were performed using the dew point chilled-mirror method on days 0, 3, and 8. On days 0 and 8, microbiological, physicochemical, and organoleptic assessments were performed. RESULTS It was established that under these storage conditions, the processed raw materials exhibited water activity below 0.60 during the entire holding time. However, there were statistically significant differences in water activity levels between days 0, 3, and 8 (ANOVA P < 0.05). Despite observing statistically significant differences between days, the microbiological, physicochemical, and organoleptic features were within specification at those water activity levels below 0.60. CONCLUSIONS Water activity below 0.60 does not allow the growth of microorganisms, and the organoleptic and physicochemical features remain unperturbed. The results indicate that water activity can be used as an indicator of the microbiological load and chemical stability of the raw materials tested. HIGHLIGHTS This research provides evidence that corroborates that water activity status may be used as a reliable indicator for the microbiological burden and physicochemical features of pharmaceutical material during stability studies.
Collapse
Affiliation(s)
| | - Juan Pablo Montes-Tamara
- Universidad de Sucre, Departamento de Biología y Química, Facultad de Educación y Ciencias, 28 #5-267, Campus Red Door, Bogotá 700003, Colombia
| | | | | |
Collapse
|
2
|
Liu S, Qiu Y, Ji K, Ozturk S, Erdoğdu F, Qin W, Yang R, Wu Q. Effect of oil exposure stages on the heat resistance of Salmonella enterica serovar Enteritidis phage type 30 in peanut flour. Food Microbiol 2023; 113:104275. [PMID: 37098433 DOI: 10.1016/j.fm.2023.104275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 04/03/2023] [Accepted: 04/03/2023] [Indexed: 04/08/2023]
Abstract
The oil in low-moisture foods (LMFs) shows protective effects on bacteria during thermal processing. However, the circumstances under which this protective effect strengthens remain unclear. This study aimed to understand which step of the oil exposure to bacterial cells (inoculation, isothermal inactivation, or recovery and enumeration step) in LMFs can enhance their heat resistance. Peanut flour (PF) and defatted PF (DPF) were selected as the oil-rich and oil-free LMF models. Salmonella enterica Enteritidis Phage Type 30 (S. Enteritidis) was inoculated into four designated PF groups representing different oil exposure stages. It was isothermally treated to obtain heat resistance parameters. At a constant moisture content (aw,25°C = 0.32 ± 0.02) and controlled aw,85°C (0.32 ± 0.02), S. Enteritidis exhibited significantly high (p < 0.05) D values in oil-rich sample groups. For instance, the heat resistance values of S. Enteritidis in the PF-DPF and DPF-PF groups were D80°C of 138.22 ± 7.45 min and 101.89 ± 7.82 min; however, the D80°C in the DPF-DPF group was 34.54 ± 2.07 min. The oil addition after the thermal treatment also helped injured bacterial recovery in the enumeration. For instance, the D80°C, D85°C, and D90°C values in the DFF-DPF oil groups were 36.86 ± 2.30, 20.65 ± 1.23, and 7.91 ± 0.52 min, respectively, which were higher than those in the DPF-DPF group at 34.54 ± 2.07, 17.87 ± 0.78, and 7.10 ± 0.52 min. We confirmed that the oil protected S. Enteritidis in PF in all three stages: desiccation process, heat treatment, and recovery of bacterial cells in plates.
Collapse
|
3
|
Xu S, Chen H. The influence of almond's water activity and storage temperature on Salmonella survival and thermal resistance. Food Microbiol 2023; 113:104269. [PMID: 37098429 DOI: 10.1016/j.fm.2023.104269] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 03/21/2023] [Accepted: 03/21/2023] [Indexed: 03/29/2023]
Abstract
This study investigated the effects of inoculation method, water activity (aw), packaging method, and storage temperature and duration on the survival of Salmonella on almonds as well as their resistance to subsequent thermal treatments. Whole almond kernels were inoculated with a broth-based or agar-based growth Salmonella cocktail and conditioned to aw of 0.52, 0.43 or 0.27. Inoculated almonds with aw of 0.43 were treated with a previously validated treatment (4 h of dry heat at 73 °C) to determine the potential differences in heat resistance resulted from the two inoculation methods. The inoculation method did not significantly (P > 0.05) impact the thermal resistance of Salmonella. Inoculated almonds at aw of 0.52 and 0.27 were either vacuum packaged in moisture-impermeable mylar bags or non-vacuum packaged in moisture-permeable polyethylene bags before stored at 35, 22, 4, or -18 °C for up to 28 days. At selected storage intervals, almonds were measured for aw, analyzed for Salmonella population level, and subjected to dry heat treatment at 75 °C. Over the month-long storage of almonds, Salmonella populations remained almost unchanged (<0.2 log CFU/g) at 4 °C and -18 °C and declined slightly (<0.8 log CFU/g) at 22 °C and more substantially (1.6-2.0 log CFU/g) at 35 °C regardless of the inoculation method, packaging method, and almond aw. When stored at 35 °C, almonds with initial aw of 0.52 had significantly higher (P < 0.05) Salmonella reductions than those with initial aw of 0.27. Prior storage of almonds vacuum packaged in mylar bags at temperatures between -18 °C and 35 °C for 28 days affected their aw levels but did not significantly (P > 0.05) affect the subsequent thermal resistance of Salmonella at 75 °C regardless of almond aw and storage duration. Salmonella on almonds with higher aw was more sensitive to heat treatment than those with lower aw. To achieve >5 log CFU/g reductions of Salmonella, a dry heat treatment at 75 °C for 4 and 6 h was needed for almonds with initial aw of 0.52 and 0.27, respectively. When applying the dry heating technology for almond decontamination, the processing time needs to be determined based on initial aw of almonds regardless of storage condition or age of almonds within the current design frame.
Collapse
|
4
|
Practice and Progress: Updates on Outbreaks, Advances in Research, and Processing Technologies for Low-moisture Food Safety. J Food Prot 2023; 86:100018. [PMID: 36916598 DOI: 10.1016/j.jfp.2022.11.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 11/03/2022] [Accepted: 11/20/2022] [Indexed: 12/31/2022]
Abstract
Large, renowned outbreaks associated with low-moisture foods (LMFs) bring to light some of the potential, inherent risks that accompany foods with long shelf lives if pathogen contamination occurs. Subsequently, in 2013, Beuchat et al. (2013) noted the increased concern regarding these foods, specifically noting examples of persistence and resistance of pathogens in low-water activity foods (LWAFs), prevalence of pathogens in LWAF processing environments, and sources of and preventive measures for contamination of LWAFs. For the last decade, the body of knowledge related to LMF safety has exponentially expanded. This growing field and interest in LMF safety have led researchers to delve into survival and persistence studies, revealing that some foodborne pathogens can survive in LWAFs for months to years. Research has also uncovered many complications of working with foodborne pathogens in desiccated states, such as inoculation methods and molecular mechanisms that can impact pathogen survival and persistence. Moreover, outbreaks, recalls, and developments in LMF safety research have created a cascading feedback loop of pushing the field forward, which has also led to increased attention on how industry can improve LMF safety and raise safety standards. Scientists across academia, government agencies, and industry have partnered to develop and evaluate innovate thermal and nonthermal technologies to use on LMFs, which are described in the presented review. The objective of this review was to describe aspects of the extensive progress made by researchers and industry members in LMF safety, including lessons-learned about outbreaks and recalls, expansion of knowledge base about pathogens that contaminate LMFs, and mitigation strategies currently employed or in development to reduce food safety risks associated with LMFs.
Collapse
|
5
|
Ahmad NH, Marks BP, Ryser ET. Effect of Lactose and Milk Protein on Thermal Resistance of Enterococcus faecium NRRL B-2354 and Salmonella in Dairy Powders. J Food Prot 2022; 85:1865-1874. [PMID: 36173901 DOI: 10.4315/jfp-22-111] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 09/26/2022] [Indexed: 11/11/2022]
Abstract
ABSTRACT Microbial challenge studies using nonpathogenic surrogates provide a practical means for validating thermally based pathogen controls for low-moisture foods. Because the relative thermal resistance, or kill ratio, of Enterococcus faecium NRRL B-2354 (a nonpathogenic surrogate) to Salmonella is greatly influenced by food composition, this study assessed relative thermal resistance of a five-strain Salmonella cocktail and E. faecium in skim milk powder (SMP), lactose-free skim milk powder (LSMP), 90% milk protein isolate (MPI), and lactose powder (LP). The impact of sugar composition (lactose versus glucose-galactose) on resuscitation of bacterial survivors, by using SMP and LSMP, was also determined. Dairy powders were inoculated with agar-grown cultures, mixed, preequilibrated at 0.25 water activity (aw), ground to achieve homogeneity, reequilibrated, and subjected to isothermal treatment. After enumeration on nonselective differential media, log-linear and Bigelow models were fit to the survivor data via one-step global regression. The aw changes and glass transition temperature were assessed at elevated temperatures by using uninoculated, equilibrated powder samples. Estimated D90°C-values were approximately two times higher for E. faecium (P < 0.05) than for Salmonella in SMP, LP, and MPI, but statistically similar (P > 0.05) in LSMP. Addition of sugars to recovery media did not influence survivor resuscitation from heat-treated SMP and LSMP, confirming that microbial inactivation was impacted primarily by the thermal treatment, not the recovery step. Thermally induced changes in aw were seen only for LP and MPI, with the glass transition temperature observed only for SMP and MPI. In conclusion, rather than always requiring greater lethality of E. faecium than Salmonella, these findings suggest that sufficient pathogen controls for low-moisture foods can also be validated by thoroughly documenting the appropriate kill ratios of E. faecium to Salmonella. HIGHLIGHTS
Collapse
Affiliation(s)
- Nurul Hawa Ahmad
- Department of Food Science and Human Nutrition, Michigan State University, East Lansing, Michigan 48824, USA
| | - Bradley P Marks
- Department of Biosystem and Agricultural Engineering, Michigan State University, East Lansing, Michigan 48824, USA
| | - Elliot T Ryser
- Department of Food Science and Human Nutrition, Michigan State University, East Lansing, Michigan 48824, USA
| |
Collapse
|
6
|
Morasi RM, Rall VLM, Dantas STA, Alonso VPP, Silva NCC. Salmonella spp. in low water activity food: Occurrence, survival mechanisms, and thermoresistance. J Food Sci 2022; 87:2310-2323. [PMID: 35478321 DOI: 10.1111/1750-3841.16152] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 03/04/2022] [Accepted: 03/22/2022] [Indexed: 01/17/2023]
Abstract
The occurrence of disease outbreaks involving low-water-activity (aw ) foods has gained increased prominence due in part to the fact that reducing free water in these foods is normally a measure that controls the growth and multiplication of pathogenic microorganisms. Salmonella, one of the main bacteria involved in these outbreaks, represents a major public health problem worldwide and in Brazil, which highlights the importance of good manufacturing and handling practices for food quality. The virulence of this pathogen, associated with its high ability to persist in the environment, makes Salmonella one of the main challenges for the food industry. The objectives of this article are to present the general characteristics, virulence, thermoresistance, control, and relevance of Salmonella in foodborne diseases, and describe the so-called low-water-activity foods and the salmonellosis outbreaks involving them.
Collapse
Affiliation(s)
- Rafaela Martins Morasi
- Department of Food Sciences And Nutrition, Faculty of Food Engineering, State University of Campinas (UNICAMP), Monteiro Lobato Street, 80, Campinas, São Paulo, Brazil
| | - Vera Lúcia Mores Rall
- Sector of Microbiology and Immunology, Department of Chemical and Biological Sciences, Institute of Biosciences of Botucatu, São Paulo State University (UNESP), Botucatu, Brazil
| | - Stéfani Thais Alves Dantas
- Sector of Microbiology and Immunology, Department of Chemical and Biological Sciences, Institute of Biosciences of Botucatu, São Paulo State University (UNESP), Botucatu, Brazil
| | - Vanessa Pereira Perez Alonso
- Department of Food Sciences And Nutrition, Faculty of Food Engineering, State University of Campinas (UNICAMP), Monteiro Lobato Street, 80, Campinas, São Paulo, Brazil
| | - Nathália Cristina Cirone Silva
- Department of Food Sciences And Nutrition, Faculty of Food Engineering, State University of Campinas (UNICAMP), Monteiro Lobato Street, 80, Campinas, São Paulo, Brazil
| |
Collapse
|
7
|
Thermal inactivation of Salmonella, Listeria monocytogenes and Enterococcus faecium NRRL B-2354 in desiccated shredded coconut. Lebensm Wiss Technol 2021. [DOI: 10.1016/j.lwt.2021.111851] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
8
|
Thermal inactivation of Salmonella Enteritidis PT30 in ground cinnamon as influenced by water activity and temperature. Food Control 2021. [DOI: 10.1016/j.foodcont.2021.107935] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
|
9
|
Dhowlaghar N, Zhu MJ. Control of Salmonella in low-moisture foods: Enterococcus faecium NRRL B-2354 as a surrogate for thermal and non-thermal validation. Crit Rev Food Sci Nutr 2021; 62:5886-5902. [PMID: 33798006 DOI: 10.1080/10408398.2021.1895055] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Salmonella has been implicated in multiple foodborne outbreaks and recalls associated with low water activity foods (LawF). To verify the effectiveness of a process against Salmonella in LawF, validation using a nonpathogenic surrogate strain is essential. Enterococcus faecium NRRL B-2354 strain has been used as a potential surrogate of Salmonella in different processing of LawF. However, the survival of Salmonella and E. faecium in LawF during food processing is a dynamic function of aw, food composition and structure, processing techniques, and other factors. This review assessed pertinent literature on the thermal and non-thermal inactivation of Salmonella and its presumable surrogate E. faecium in various LawF and provided an overview of its suitibility in different LawF. Overall, based on the D-values, survival/reduction, temperature/time to obtain 4 or 5-log reductions, most studies concluded that E. faecium is a suitable surrogate of Salmonella during LawF processing as its magnitude of resistance was slightly greater or equal (i.e., statistical similar) as compared to Salmonella. Studies also showed its unsuitability which either does not provide a proper margin of safety or being overly resistant and may compromise the quality and organoleptic properties of food. This review provides useful information and guidance for future validation studies of LawF.
Collapse
Affiliation(s)
- Nitin Dhowlaghar
- School of Food Science, Washington State University, Pullman, Washington, USA
| | - Mei-Jun Zhu
- School of Food Science, Washington State University, Pullman, Washington, USA
| |
Collapse
|